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#1
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Question about distortion
Can playing a song that has distortion in it cause damage to speakers?
I don't mean the equipment itself causing the distortion, but distortion in the recording itself. For example, Neil Young's "Hey Hey, My My (Into the Black)" is a good example of a song with distortion. Another one I can think of would be "Revolution" by the Beatles. Would playing either of these songs loudly cause damage to speakers? Thanks |
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#2
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nope.
I can personally vouch for the Neil Young stuff. "Sm704" wrote in message m... Can playing a song that has distortion in it cause damage to speakers? I don't mean the equipment itself causing the distortion, but distortion in the recording itself. For example, Neil Young's "Hey Hey, My My (Into the Black)" is a good example of a song with distortion. Another one I can think of would be "Revolution" by the Beatles. Would playing either of these songs loudly cause damage to speakers? Thanks |
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#3
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#4
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Can playing a song that has distortion in it cause damage to speakers?
I don't mean the equipment itself causing the distortion, but distortion in the recording itself. For example, Neil Young's "Hey Hey, My My (Into the Black)" is a good example of a song with distortion. Another one I can think of would be "Revolution" by the Beatles. Would playing either of these songs loudly cause damage to speakers? There's nothing magical about distortion that makes it immune to the laws of physics. After all, the speaker doesn't KNOW whether or not your amplifier or source is distorting. It's impossible for distortion, in and of itself, to cause harm to speakers. The only way to damage a speaker is to exceed its thermal or mechanical limits. Therefore, the only way to blow a speaker is to give it too much power. If this is done with the assistance of distortion, then that's one thing. Attributing it to distortion alone would be a mistake. There are some spectral properties associated with some forms of distortion that could potentially be damaging to some forms of speakers, IF you're playing it loud enough. For instance, harmonic distortion tends to add to the high frequency content of the signal, producing higher power content at higher frequencies. If you're playing loud enough, and the distortion is high enough, you could be dumping more power into your tweeters or midrange drivers than you would be if it wasn't distortion - hence, increasing the chance of blowing the speaker. But the key point to remember here is that it's the power that the speaker is receiving that's the determining factor. Distortion in Neil Young's song could be introducing a higher power content in the high frequency range than you'd find in other music. Just as the higher power content in the bass region typically found in, say, rap music or some forms of rock music could potentially be more damaging to subwoofers than Barbara Streisand's music. So it's all about frequency content. |
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#5
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Distortion on a recording is simply that. The amplifier receives a signal,
and amplifies it. The only distortion that is really going to damage speakers is that created by yourself. By overdriving a component. Another reply mentions the way that spekaers blow. This is theoretically true. however more often than not it is problems that occur BEFORE the speaker itself that cuases them to blow. The main cause of speakers blowing is amplifier clipping. When the power supply of a power amp cannot produce any more power the signal "clips" Imagine a sine wave, with the top and bottom cut off (flattened) This is clipping. This will create distortion. If you imagine the movement of a speaker cone. it moves back and forth dependant on the material played. its constantly changing. like an AC wave (mains electricity) When an amplifier clips you get a flat part at the top and bottom of the sound wave. when the speaker cone is NOT moving. This is a DC signal. and can easily damage your speakers (particularly tweeters). Distortion on a record does not cause this effect providing you are within the limits of your amplifier and speakers. Putting 500watts through a 100watt speaker is quite common and will not damage the driver if used correctly. Rob ----- Original Message ----- From: "Scott Johnson" Newsgroups: rec.audio.car Sent: Thursday, October 14, 2004 11:31 PM Subject: Question about distortion nope. I can personally vouch for the Neil Young stuff. "Sm704" wrote in message m... Can playing a song that has distortion in it cause damage to speakers? I don't mean the equipment itself causing the distortion, but distortion in the recording itself. For example, Neil Young's "Hey Hey, My My (Into the Black)" is a good example of a song with distortion. Another one I can think of would be "Revolution" by the Beatles. Would playing either of these songs loudly cause damage to speakers? Thanks "Sm704" wrote in message m... Can playing a song that has distortion in it cause damage to speakers? I don't mean the equipment itself causing the distortion, but distortion in the recording itself. For example, Neil Young's "Hey Hey, My My (Into the Black)" is a good example of a song with distortion. Another one I can think of would be "Revolution" by the Beatles. Would playing either of these songs loudly cause damage to speakers? Thanks |
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#6
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When an amplifier clips you get a flat part at the top and bottom of the
sound wave. when the speaker cone is NOT moving. I'm sorry, but this is simply not true. Indeed, the clipped waveform has flat peaks, but the speaker won't stand still. The flat peaks are not of a long enough duration for this to occur. The inductance of the speaker coil filters this out. This can be demonstrated by looking at the spectral characteristics of the clipped signal and simply noting the inductance of the voice coil. This is a DC signal. No it's not. Even a square wave isn't DC. DC, by definition, can't alternate. and can easily damage your speakers (particularly tweeters). Distortion on a record does not cause this effect providing you are within the limits of your amplifier and speakers. What if you record a square wave? If you overdrive an amplifier, you'll get a clipped signal. If you overdrive your recording equipment, you'll also get a clipped signal. There's no difference between the two. Putting 500watts through a 100watt speaker is quite common and will not damage the driver if used correctly. Then you're either not truly delivering 500 watts to the speaker, or the speaker is not truly a 100 watt speaker. By definition, a 100 watt speaker can only safely handle 100 watts at a continuous rate. Sure, it can handle higher power transients, but that's not really the issue. |
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#7
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I just wanted to add one thing about the spectral content of a recording. Even
Compact Discs with their wide-band capabilities will not contain the high frequency distortion of an amplifier driven into clipping. The chain of recording during an album's production (unintentionally) removes it. CD players also have bandwidth limiting filters and therefore could never playback a square wave. Kevin Murray "Mark Zarella" wrote in message ... Can playing a song that has distortion in it cause damage to speakers? I don't mean the equipment itself causing the distortion, but distortion in the recording itself. For example, Neil Young's "Hey Hey, My My (Into the Black)" is a good example of a song with distortion. Another one I can think of would be "Revolution" by the Beatles. Would playing either of these songs loudly cause damage to speakers? There's nothing magical about distortion that makes it immune to the laws of physics. After all, the speaker doesn't KNOW whether or not your amplifier or source is distorting. It's impossible for distortion, in and of itself, to cause harm to speakers. The only way to damage a speaker is to exceed its thermal or mechanical limits. Therefore, the only way to blow a speaker is to give it too much power. If this is done with the assistance of distortion, then that's one thing. Attributing it to distortion alone would be a mistake. There are some spectral properties associated with some forms of distortion that could potentially be damaging to some forms of speakers, IF you're playing it loud enough. For instance, harmonic distortion tends to add to the high frequency content of the signal, producing higher power content at higher frequencies. If you're playing loud enough, and the distortion is high enough, you could be dumping more power into your tweeters or midrange drivers than you would be if it wasn't distortion - hence, increasing the chance of blowing the speaker. But the key point to remember here is that it's the power that the speaker is receiving that's the determining factor. Distortion in Neil Young's song could be introducing a higher power content in the high frequency range than you'd find in other music. Just as the higher power content in the bass region typically found in, say, rap music or some forms of rock music could potentially be more damaging to subwoofers than Barbara Streisand's music. So it's all about frequency content. |
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#8
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I just wanted to add one thing about the spectral content of a recording.
Even Compact Discs with their wide-band capabilities will not contain the high frequency distortion of an amplifier driven into clipping. The chain of recording during an album's production (unintentionally) removes it. CD players also have bandwidth limiting filters and therefore could never playback a square wave. These filters are anti-aliasing filters, and should therefore not impinge upon the general 20-20k though. I'm not so sure that the stuff above 20kHz is going to matter to most drivers. So I think you could conceivably reproduce the effects of clipping in the studio. However, every amp clips differently so you'd have to take that into account. |
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#9
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Can playing a song that has distortion in it cause damage to speakers?
The distortion in a recording, usually is processed so that it becomes a desired audio wave that will not damage your speakers. The distortion a bad amp, or one too low to power your speakers, is what causes damage. Also, playing something with so much distorted bass or volume that you hear the distortion in the speakers that goes away as soon as you turn the volume or bass down, is what does the damage. As soon as you hear that, and turn it down so it goes away, staying at that level will keep your speakers from damage. I don't mean the equipment itself causing the distortion, but distortion in the recording itself. For example, Neil Young's "Hey Hey, My My (Into the Black)" is a good example of a song with distortion. Keep in mind they mixed and processed the distortion so that it was a good sounding effect, but had no damage on their expensive studio monitors. Many Classical CDs have warnings on them about damage that could be caused to speakers because of the vast dynamic range, and cannon shots or what not that suddenly drive more power to your speakers than the level of the rest of the music could indeed damage your speakers if you had the rest of the music right on the edge of safety as far as the volume you were playing that. Another one I can think of would be "Revolution" by the Beatles. Would playing either of these songs loudly cause damage to speakers? Not if you play them at a level in which your speakers don't sound like they are being damaged. I am sure you are familiar with turning up a standard cheap stereo or boombox so loud that the speakers start sounding like **** and distorting. THAT is what damages them. Turn it down to the point where they don't sound all distorted, then turn it down one more notch, and you can play all those songs without any fear. |
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#10
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The distortion in a recording, usually is processed so that it becomes a
desired audio wave that will not damage your speakers. How? The distortion a bad amp, or one too low to power your speakers, is what causes damage. How on earth can a speaker be damaged with too little power? Also, playing something with so much distorted bass or volume that you hear the distortion in the speakers that goes away as soon as you turn the volume or bass down, is what does the damage. As soon as you hear that, and turn it down so it goes away, staying at that level will keep your speakers from damage. Actually, I've blown plenty of speakers before without distortion being present first. A lot of times, the earliest cue is the smell! |
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#11
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When an amplifier clips you get a flat part at the top and bottom of the
sound wave. when the speaker cone is NOT moving. By that logic, you could never hear a square wave tone on speakers. But you can. Putting 500watts through a 100watt speaker is quite common and will not damage the driver if used correctly. You can play a 500 watt amp so that only 20 watts are going to that 100 watt speaker. Just connection a 500 watt amp to a speaker doesn't mean 500 watts are going to that speaker. If you did turn it up to that level, your speaker coil would melt and open the circuit. |
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#12
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When an amplifier clips you get a flat part at the top and bottom of
the sound wave. when the speaker cone is NOT moving. By that logic, you could never hear a square wave tone on speakers. But you can. I think what he meant was that the speaker would follow the electrical signal perfectly and that the driver would stand still on the flat parts of the square wave. This would indeed result in a "square wave tone". It has to. If the speaker is moving as a square wave (which it doesn't, as I pointed out in my reply), then it MUST by definition produce a "square wave tone". |
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#13
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When an amplifier clips you get a flat part at the top and bottom of
the sound wave. when the speaker cone is NOT moving. By that logic, you could never hear a square wave tone on speakers. But you can. I think what he meant was that the speaker would follow the electrical signal perfectly and that the driver would stand still on the flat parts of the square wave. Doesn't matter what he meant, once this excellent example was brought up and realized. Now even this guy can instantly see how wrong his statement was just by thinking about this example. This would indeed result in a "square wave tone". It has to. If the speaker is moving as a square wave (which it doesn't If the speaker didn't move, then you would not hear anything. You CAN hear a square wave tone, thus the speaker is moving and vibrations through the air are moving your ear drums in the same exact frequency of movement. A vote for Kerry is a vote for Bush. |
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#14
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The distortion in a recording, usually is processed so that it becomes a
desired audio wave that will not damage your speakers. How? Limiting peaks, compression, Equalization to smooth it out. Distortion is only used in music as an effect for how it sounds, not with the intent to cause spikes and damage to speakers. The distortion a bad amp, or one too low to power your speakers, is what causes damage. How on earth can a speaker be damaged with too little power? Take two amps. One is 50 watts, the other 500 watts. Now play them both at 50 watts through a 100 watt speaker. Which one is going to ruin the speaker? The 50 watt one. Now see if you can figure out why. Also, playing something with so much distorted bass or volume that you hear the distortion in the speakers that goes away as soon as you turn the volume or bass down, is what does the damage. As soon as you hear that, and turn it down so it goes away, staying at that level will keep your speakers from damage. Actually, I've blown plenty of speakers before without distortion being present first. Because your ears are obviously not trained to hear distortion as well as many of us can. I constantly have to tell people to turn down the volume that they are damaging their speakers just by the obvious sound that they claim they can't hear. A lot of times, the earliest cue is the smell! No, the horrible annoying sound is the most obvious cue. |
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#15
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This would indeed result in a "square wave tone". It has
to. If the speaker is moving as a square wave (which it doesn't If the speaker didn't move, then you would not hear anything. He didn't say it wouldn't move at all. He said it wouldn't move at the saturated regions of the wave - the "flat tops" so to speak. It would indeed produce a square wave tone. According to your logic, a speaker reproducing a perfect square wave wouldn't make a sound because it would be standing still for the bulk of the duty cycle. This is obviously untrue! The motion comes during the transition from -A to +A and from +A to -A. Even though it's a nearly instantaneous transition, it's a transition nonetheless and will move air. Because it's periodic, the fundamental frequency will be governed by the number of times it undergoes a transition in one direction per second. So if it was moving out, staying still, moving in, staying still 40 times per second, the fundamental would be 40Hz. The higher frequency components take the form of the fast transitions themselves. If you were to assume, say, a linear velocity from -A to +A, you could actually determine the spectral content of the wave rather easily. It would look something like a series of odd order harmonics of amplitude 1/n, where n is the nth harmonic. The easy way to look at it is to simply take a square wave and examine its spectral content (you can do this in cool edit or other software that you can find on the net). You'll note that there are frequency components within audible range. Obviously, then, you can hear this. So if a square wave doesn't produce a square wave tone, what does??? |
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#16
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How?
Limiting peaks, compression, Equalization to smooth it out. Distortion is only used in music as an effect for how it sounds, not with the intent to cause spikes and damage to speakers. Compression isn't going to change the waveform itself, other than to adjust the amplitude during transients. And equalization wouldn't work either, unless you filtered out the bulk of the signal. That's obviously not done. The spectral content of guitar distortion, for instance, tends to be quite different from distortion resulting from our audio amplifiers clipping. But what does that matter? From a broadband perspective (which is all a speaker "cares" about anyway), it's got roughly the same power content - maybe a little closer to the fundamental. So you're no more or less likely to blow your speakers with the distortion from the source or distortion from the amplifier. I don't quite understand how you're attributing more power to one of the scenarios based on waveform alone. The distortion a bad amp, or one too low to power your speakers, is what causes damage. How on earth can a speaker be damaged with too little power? Take two amps. One is 50 watts, the other 500 watts. Now play them both at 50 watts through a 100 watt speaker. Which one is going to ruin the speaker? The 50 watt one. Now see if you can figure out why. I can't figure out why because it's not true! So instead of playing guessing games, why don't you just tell me why you think the 50 watt amplifier is going to blow the 100 watt speaker. While you're at it, explain to me how the output signal is different between the two amplifiers when they're both producing 50 watts. Actually, I've blown plenty of speakers before without distortion being present first. Because your ears are obviously not trained to hear distortion as well as many of us can. Nice try. If the amplifier is not producing distortion, then the only way to produce distortion is by overdriving the speaker beyond its mechanical limits or by delivering too high a frequency content to the speaker so that it cannot accurately reproduce the signal. So, if you're not exceeding the mechanical limits of the driver, but you're exceeding its thermal limits, you won't hear any distortion but you'll blow the speaker anyway. What part of this do you disagree with? |
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#17
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I'd agree that in a studio spectral content below 20kHz can blow drivers. My
point is that most tweeters can be smoked by 30kHz just as easily as 20kHz. The steep rising edge of a severely clipped wave is caused by the ultra sound content and it's presence makes it easier to exceed the power limits of a tweeter. This is easy to do when the driver is fed a wideband "rail to rail" signal, and is probably why the "distortion kills tweeters" generalisation exists. The output bandwidth of a CD player is limited and this makes it much safer when reproducing a distorted recording. While it is possible to destroy a driver with a distorted recording when the amplifier is not at it's output limit, once an amplifier begins clipping the spectral content increases enormously. I haven't been very active on this newsgroup the past few months. It got kinda depressing with the same old posts every time I checked in. Has anyone got anything interesting to report? Anyone making their own gear? Anyone tryin to screw with the competition rules? I was stonewalled when I found out that my home-made gear automatically puts me in the highest competition class. Someday I plan to stuff it all into commercial chassis and try to enter again with "inexpensive" commercial stuff. Share your stories... Kevin Murray "MZ" wrote in message ... I just wanted to add one thing about the spectral content of a recording. Even Compact Discs with their wide-band capabilities will not contain the high frequency distortion of an amplifier driven into clipping. The chain of recording during an album's production (unintentionally) removes it. CD players also have bandwidth limiting filters and therefore could never playback a square wave. These filters are anti-aliasing filters, and should therefore not impinge upon the general 20-20k though. I'm not so sure that the stuff above 20kHz is going to matter to most drivers. So I think you could conceivably reproduce the effects of clipping in the studio. However, every amp clips differently so you'd have to take that into account. |
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#18
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I'd agree that in a studio spectral content below 20kHz can blow drivers.
My point is that most tweeters can be smoked by 30kHz just as easily as 20kHz. The steep rising edge of a severely clipped wave is caused by the ultra sound content and it's presence makes it easier to exceed the power limits of a tweeter. This is easy to do when the driver is fed a wideband "rail to rail" signal, and is probably why the "distortion kills tweeters" generalisation exists. The output bandwidth of a CD player is limited and this makes it much safer when reproducing a distorted recording. While it is possible to destroy a driver with a distorted recording when the amplifier is not at it's output limit, once an amplifier begins clipping the spectral content increases enormously. But is the 20kHz content even significant? Indeed, it's present when clipping occurs. But, first of all, clipping usually occurs at lower frequencies (where the spectral content is higher in "typical" music), and as such, the content at ultrasonic frequencies would be miniscule. Second, even tweeters often exhibit a huge increase in impedance at these frequencies. It's not uncommon for the impedance to be twice its nominal impedance at around 15kHz, and steadily increasing at higher frequencies. I haven't been very active on this newsgroup the past few months. It got kinda depressing with the same old posts every time I checked in. Has anyone got anything interesting to report? Anyone making their own gear? Anyone tryin to screw with the competition rules? I was stonewalled when I found out that my home-made gear automatically puts me in the highest competition class. Someday I plan to stuff it all into commercial chassis and try to enter again with "inexpensive" commercial stuff. Share your stories... Nothing new around here. Your plan sounds very cool though. Say the word and I'll try to round up some old Jensen chassis to house your stuff! The judges will frown of course, because anything with "Jensen" on it must be bad. So I've been considering building an ADC lately, but that's about all the homebrew news I've got. I'm running a PC USB sound card with a toslink output to a zapco DAC. Works great. But I have some analog external pieces (USB FM radio, and pretty soon I'll add XM and/or Sirius) that need to adapt. The problem is that the analog input of the sound card does not adapt to accomodate the digital output, so I need to build an ADC for these devices and run it into the optical input of the sound card. I'll have to use some sort of auto-sensing circuit or PC-controlled switch to switch between the three devices in the analog domain and then just run it through an ADC IC and convert it to an optical output. Any suggestions? |
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#19
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This would indeed result in a "square wave tone". It has
to. If the speaker is moving as a square wave (which it doesn't If the speaker didn't move, then you would not hear anything. He didn't say it wouldn't move at all. He said it wouldn't move at the saturated regions of the wave - the "flat tops" so to speak. My god. The bigger the wave, the more the speaker moves and louder the sound. Are you people still arguing and debating over the obvious? According to your logic, a speaker reproducing a perfect square wave wouldn't make a sound because it would be standing still for the bulk of the duty cycle. This is obviously untrue! The motion comes during the transition from -A to +A and from +A to -A. Even though it's a nearly instantaneous transition, it's a transition nonetheless and will move air. Because it's periodic, the fundamental frequency will be governed by the number of times it undergoes a transition in one direction per second. So if it was moving out, staying still, moving in, staying still 40 times per second, the fundamental would be 40Hz. The higher frequency components take the form of the fast transitions themselves. If you were to assume, say, a linear velocity from -A to +A, you could actually determine the spectral content of the wave rather easily. It would look something like a series of odd order harmonics of amplitude 1/n, where n is the nth harmonic. Oh my god, look at all this algebra and equations over something so obvious and simple. Keep in mind too, that most of the time, what looks good on paper and theory, is not how things are in reality. We would all like to have an Isotropic antenna, but it only exists on paper and you can use all sorts of formulas and math to argue about it, but in reality no antenna works the way it does on paper. I think you people are dealing with imaginary isotropic speakers and not the same real ones I use. |
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#20
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Limiting peaks, compression, Equalization to smooth it out.
Distortion is only used in music as an effect for how it sounds, not with the intent to cause spikes and damage to speakers. Compression isn't going to change the waveform itself You have obviously never seen or used a digital audio workstation. the amplitude during transients. And equalization wouldn't work either, Don't talk and debate about things you don't have any knowledge or experience about. I deal with this stuff every day, and I also don't say something unless I know what I am talking about. How on earth can a speaker be damaged with too little power? Take two amps. One is 50 watts, the other 500 watts. Now play them both at 50 watts through a 100 watt speaker. Which one is going to ruin the speaker? The 50 watt one. Now see if you can figure out why. I can't figure out why And that is the reason you are not qualified to even be in this debate. If the amplifier is not producing distortion The 50 watt amplifier playing at 50 watts is producing lots of distortion, the 500 watt amp only being used at 50 watts is much cleaner with much less distortion. I am not going to beat a dead human, if it isn't clear this time, then further debate would only be wasted effort. |
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#21
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If the speaker didn't move, then you would not hear anything.
He didn't say it wouldn't move at all. He said it wouldn't move at the saturated regions of the wave - the "flat tops" so to speak. My god. The bigger the wave, the more the speaker moves and louder the sound. Are you people still arguing and debating over the obvious? Where on earth did you come up with that from what I said? Nobody was talking about varying the amplitude of the wave. According to your logic, a speaker reproducing a perfect square wave wouldn't make a sound because it would be standing still for the bulk of the duty cycle. This is obviously untrue! The motion comes during the transition from -A to +A and from +A to -A. Even though it's a nearly instantaneous transition, it's a transition nonetheless and will move air. Because it's periodic, the fundamental frequency will be governed by the number of times it undergoes a transition in one direction per second. So if it was moving out, staying still, moving in, staying still 40 times per second, the fundamental would be 40Hz. The higher frequency components take the form of the fast transitions themselves. If you were to assume, say, a linear velocity from -A to +A, you could actually determine the spectral content of the wave rather easily. It would look something like a series of odd order harmonics of amplitude 1/n, where n is the nth harmonic. Oh my god, look at all this algebra and equations over something so obvious and simple. I don't see any algebra or equations. Keep in mind too, that most of the time, what looks good on paper and theory, is not how things are in reality. Only if the theory is incorrect or doesn't take into account all the variables. We would all like to have an Isotropic antenna, but it only exists on paper and you can use all sorts of formulas and math to argue about it, but in reality no antenna works the way it does on paper. I think you people are dealing with imaginary isotropic speakers and not the same real ones I use. I think you have no idea what you're talking about, and so you continue to argue even though you have no point. |
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#22
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Compression isn't going to change the waveform itself
You have obviously never seen or used a digital audio workstation. You're making assumptions. Instead of doing that, why don't you tell me why I'm wrong instead? Please explain how compression changes the waveform. Now, for clarification, in case you didn't get it below, it's important that I point out that my statement implies that the spectral content of the signal *as a function of time* will not change. the amplitude during transients. And equalization wouldn't work either, Don't talk and debate about things you don't have any knowledge or experience about. I deal with this stuff every day, and I also don't say something unless I know what I am talking about. Then present your argument so that I can point out to you where you err. Until you do that, then it's safe to say that you don't know what you're talking about. How on earth can a speaker be damaged with too little power? Take two amps. One is 50 watts, the other 500 watts. Now play them both at 50 watts through a 100 watt speaker. Which one is going to ruin the speaker? The 50 watt one. Now see if you can figure out why. I can't figure out why And that is the reason you are not qualified to even be in this debate. Nice job of selective snippage. I said "I can't figure out why because it's not true!". In other words, you don't know what you're talking about. Please, explain your case so I can point out where your mistake is. You continually refuse to back your statements. I happen to believe it's because you can't. If the amplifier is not producing distortion The 50 watt amplifier playing at 50 watts is producing lots of distortion Why would it be producing distortion? What form of distortion? What is the source of this distortion? , the 500 watt amp only being used at 50 watts is much cleaner with much less distortion. I am not going to beat a dead human, if it isn't clear this time, then further debate would only be wasted effort. ....says someone who has no argument. |
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#23
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"MZ" wrote in message ... I'd agree that in a studio spectral content below 20kHz can blow drivers. My point is that most tweeters can be smoked by 30kHz just as easily as 20kHz. The steep rising edge of a severely clipped wave is caused by the ultra sound content and it's presence makes it easier to exceed the power limits of a tweeter. This is easy to do when the driver is fed a wideband "rail to rail" signal, and is probably why the "distortion kills tweeters" generalisation exists. The output bandwidth of a CD player is limited and this makes it much safer when reproducing a distorted recording. While it is possible to destroy a driver with a distorted recording when the amplifier is not at it's output limit, once an amplifier begins clipping the spectral content increases enormously. But is the 20kHz content even significant? In my opinion, not from a recorded program, but from a severely clipped amp I'd say yes. Of course that depends on the amp and the tweeters in question. Some day it would be fun to experiment. I have many different transistor amps of various design topologies, anyone want to donate a tube amp to the experiment? Didn't think so. *sigh* Indeed, it's present when clipping occurs. But, first of all, clipping usually occurs at lower frequencies (where the spectral content is higher in "typical" music), and as such, the content at ultrasonic frequencies would be miniscule. Second, even tweeters often exhibit a huge increase in impedance at these frequencies. It's not uncommon for the impedance to be twice its nominal impedance at around 15kHz, and steadily increasing at higher frequencies. I haven't been very active on this newsgroup the past few months. It got kinda depressing with the same old posts every time I checked in. Has anyone got anything interesting to report? Anyone making their own gear? Anyone tryin to screw with the competition rules? I was stonewalled when I found out that my home-made gear automatically puts me in the highest competition class. Someday I plan to stuff it all into commercial chassis and try to enter again with "inexpensive" commercial stuff. Share your stories... Nothing new around here. Your plan sounds very cool though. Say the word and I'll try to round up some old Jensen chassis to house your stuff! The judges will frown of course, because anything with "Jensen" on it must be bad. So I've been considering building an ADC lately, but that's about all the homebrew news I've got. I started a design myself for an A2D but it was for data acquisition purposes. Basically I was building a PC oscilloscope that would sample higher than 44kHz. Thing is I can buy an 8 channel one now with the software included for just over a hundred bucks. I have two Burr Brown 24bit, 96kHz stereo ADC's you can have. They will cover two of your planned three channels. I don't want anything for them, just email me with an address to send them to if you want em. Otherwise you could just buy a cheap multiplexed analog input ADC. Then of course you'd have to put the raw data into a protocol the soundcard will accept. I'm sure there must be a "solution on a chip" for what you need. Like a soundcard front end on a chip. I'm running a PC USB sound card with a toslink output to a zapco DAC. Works great. But I have some analog external pieces (USB FM radio, and pretty soon I'll add XM and/or Sirius) that need to adapt. The problem is that the analog input of the sound card does not adapt to accomodate the digital output, so I need to build an ADC for these devices and run it into the optical input of the sound card. I'll have to use some sort of auto-sensing circuit or PC-controlled switch to switch between the three devices in the analog domain and then just run it through an ADC IC and convert it to an optical output. Any suggestions? I'm surprised your digital-out doesn't include the analog inputs. It would be nice to retain use of the mixer too. I use to DJ so I guess that's where my mixer interest comes from. I know nothing about your card, I assume it has a digital input that is passed through to the digital output? A simple mux chip would allow you to select from 8 digital channels, then you have to get it into the fibre. Also, I think you have to stop and then restart a toslink feed. No dead switching it. As far as selecting from different analog inputs, there must be some sort of chip solution available for home receiver front ends? I bet there's an old garage sale receiver out there that wouldn't mind donating organs. Which components that you plan to add are digital-out and which are analog? This leaves me with more questions than answers, but it's an interesting project. It's late now so I'm going to do some googling tomorrow and look into this. Kevin Murray |
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#24
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I started a design myself for an A2D but it was for data acquisition
purposes. Basically I was building a PC oscilloscope that would sample higher than 44kHz. Thing is I can buy an 8 channel one now with the software included for just over a hundred bucks. I have two Burr Brown 24bit, 96kHz stereo ADC's you can have. They will cover two of your planned three channels. I don't want anything for them, just me with an address to send them to if you want em. That would be great. I'll email you my address shortly. I'm surprised your digital-out doesn't include the analog inputs. I'm not. They save the money that would be spent on including A-to-D conversion. I wish I knew of a soundcard that would accept analog and output digital, but they're just not out there. Not in USB at least. It would be nice to retain use of the mixer too. Ah, I will be able to retain mixer controls by using the optical input. I think there's also a separate volume control on the PC for the device itself. For the FM card, there's a "radio volume" control in the software which doesn't change any of the sound card's mixer levels. I use to DJ so I guess that's where my mixer interest comes from. I know nothing about your card, I assume it has a digital input that is passed through to the digital output? A simple mux chip would allow you to select from 8 digital channels, then you have to get it into the fibre. Also, I think you have to stop and then restart a toslink feed. No dead switching it. That's why I was considering doing the switching in the analog domain. I'll have to find an IC that can act as a low crosstalk electrically controlled switch. I guess I'll interface it with the parallel port somehow to serve as the output control. Otherwise, I'll have to run a wire all the way up to the front of the vehicle and put a switch up there somewhere. The first option seems better, but there's always the pain-in-the-ass factor. It would be easier to run a wire than it would be to incorporate software to do the switching I think. As far as selecting from different analog inputs, there must be some sort of chip solution available for home receiver front ends? I bet there's an old garage sale receiver out there that wouldn't mind donating organs. Which components that you plan to add are digital-out and which are analog? This leaves me with more questions than answers, but it's an interesting project. It's late now so I'm going to do some googling tomorrow and look into this. I have an FM card that has an analog output. I'll be adding XM which only has an analog output for the computer interface box they sell. I may add Sirius later too. |
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#25
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"MZ" wrote in message ... Compression isn't going to change the waveform itself You have obviously never seen or used a digital audio workstation. You're making assumptions. Instead of doing that, why don't you tell me why I'm wrong instead? Please explain how compression changes the waveform. Now, for clarification, in case you didn't get it below, it's important that I point out that my statement implies that the spectral content of the signal *as a function of time* will not change. the amplitude during transients. And equalization wouldn't work either, Don't talk and debate about things you don't have any knowledge or experience about. I deal with this stuff every day, and I also don't say something unless I know what I am talking about. Then present your argument so that I can point out to you where you err. Until you do that, then it's safe to say that you don't know what you're talking about. How on earth can a speaker be damaged with too little power? Take two amps. One is 50 watts, the other 500 watts. Now play them both at 50 watts through a 100 watt speaker. Which one is going to ruin the speaker? The 50 watt one. Now see if you can figure out why. I can't figure out why And that is the reason you are not qualified to even be in this debate. Nice job of selective snippage. I said "I can't figure out why because it's not true!". In other words, you don't know what you're talking about. Please, explain your case so I can point out where your mistake is. You continually refuse to back your statements. I happen to believe it's because you can't. If the amplifier is not producing distortion The 50 watt amplifier playing at 50 watts is producing lots of distortion Why would it be producing distortion? What form of distortion? What is the source of this distortion? , the 500 watt amp only being used at 50 watts is much cleaner with much less distortion. I am not going to beat a dead human, if it isn't clear this time, then further debate would only be wasted effort. ...says someone who has no argument. If we assume all ratings are RMS.(that of the 2 amps and the speaker) By putting 50 watts from any of the amps into the speaker you will not blow the speaker. However. with the smaller amp you at its rms limit. So program material with particularly loud bits in would send the signal over "50 watts" POSSIBLY causing the amplifier to clip. Its this that will damage the speaker. This means that the 500 watt smplifier has more headroom (450 watts) before it will shows signs of clipping. This is above the rating of the loudspeaker anyway. Although with a rating of 100 watts you can safely put 200 watts thrugh it with normal program material. (just not a continuous signal like a sine wave), as program material, the music we listen to has loud parts and quiet parts. Although its not the only thing. Heat build up in the driver is a cause for breakdown. Above its rms rating heat builds up quicker than it can dissipate it. but when the value drops below the rms rating. heat is lost. (again its not the only method of breakdown by power input by a long way) |
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#26
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"Mark Zarella" wrote in message ... When an amplifier clips you get a flat part at the top and bottom of the sound wave. when the speaker cone is NOT moving. I'm sorry, but this is simply not true. Indeed, the clipped waveform has flat peaks, but the speaker won't stand still. The flat peaks are not of a long enough duration for this to occur. i was explaining it in a simple form. The movement of the cone does not stop. but the wave does. at top and bottom (only for ridiculously short periods of time). The inductance of the speaker coil filters this out. This can be demonstrated by looking at the spectral characteristics of the clipped signal and simply noting the inductance of the voice coil. This is a DC signal. No it's not. Even a square wave isn't DC. DC, by definition, can't alternate. it is DC at these peaks where the signal is flattened. Which is CLEARLY what i was refering to and can easily damage your speakers (particularly tweeters). Distortion on a record does not cause this effect providing you are within the limits of your amplifier and speakers. What if you record a square wave? If you overdrive an amplifier, you'll get a clipped signal. If you overdrive your recording equipment, you'll also get a clipped signal. There's no difference between the two. any signal can clip. it is clipping in the amplifer that causes problems. Putting 500watts through a 100watt speaker is quite common and will not damage the driver if used correctly. Then you're either not truly delivering 500 watts to the speaker, or the speaker is not truly a 100 watt speaker. By definition, a 100 watt speaker can only safely handle 100 watts at a continuous rate. Sure, it can handle higher power transients, but that's not really the issue. i beleive it is an issue, as it explains that a little over the rated power (ok 500 watts is extreme) is much better than under teh rated power. |
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#27
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By putting 50 watts from any of the amps into the speaker you will not
blow the speaker. However. with the smaller amp you at its rms limit. So program material with particularly loud bits in would send the signal over "50 watts" POSSIBLY causing the amplifier to clip. I agree. If you drive the 50 watt amp beyond 50 watts, then it's clipping. But this isn't the scenario he presented. Its this that will damage the speaker. Only if it's producing more than 100 watts. Remember, the scenario he presented was a 100 watt speaker. By definition, a 100 watt speaker is capable of handling 100 watts - otherwise, it's not a 100 watt speaker. This means that the 500 watt smplifier has more headroom (450 watts) before it will shows signs of clipping. This is above the rating of the loudspeaker anyway. Although with a rating of 100 watts you can safely put 200 watts thrugh it with normal program material. (just not a continuous signal like a sine wave), as program material, the music we listen to has loud parts and quiet parts. I understand the point you're trying to make. That is, that you can deliver a signal that has 200 watt transients to the 100 watt speaker without it blowing. That's because, on average, the signal is 100 watts or under. |
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#28
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Ahhh, I think I misunderstood what you were trying to do. I thought you had some
digital and some analog sources and wanted to switch between them. If you only need to switch analog sources I'd consider three digital volume control IC's. By controlling the volume of each with your PC you could implement a mixer. Most also incorporate a mute function on a seperate input pin which could come in handy. One to consider is the Texas Instruments PGA2310 with 120dB dynamic range and 0.0004% THD+N at 1kHz, and they are daisy chainable which means you need only one serial cable to control all three IC's. You could use the +/-12V from your PC to power it. http://focus.ti.com/lit/ds/sbos207b/sbos207b.pdf I'm sure there are many more solutions-on-a-chip with less features that would be easier to implement. They probably even have one with multiple input select. It's so easy to get carried away once you start looking. I believe this one would run you around $10 each but I'm sure TI would give you three samples. |
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#29
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Ahhh, I think I misunderstood what you were trying to do. I thought you
had some digital and some analog sources and wanted to switch between them. If you only need to switch analog sources I'd consider three digital volume control IC's. By controlling the volume of each with your PC you could implement a mixer. Most also incorporate a mute function on a seperate input pin which could come in handy. One to consider is the Texas Instruments PGA2310 with 120dB dynamic range and 0.0004% THD+N at 1kHz, and they are daisy chainable which means you need only one serial cable to control all three IC's. You could use the +/-12V from your PC to power it. http://focus.ti.com/lit/ds/sbos207b/sbos207b.pdf I'm sure there are many more solutions-on-a-chip with less features that would be easier to implement. They probably even have one with multiple input select. It's so easy to get carried away once you start looking. I believe this one would run you around $10 each but I'm sure TI would give you three samples. Actually, I don't think it will be necessary. Each of the devices has its own volume control. I'm not sure how they implement it, but as I mentioned in my last post, the radio device has a "radio volume" that is independent of the aux in volume control. So the software already controls the volume. What I need, however, is to be able to implement a switch between the three that can be controlled by the computer. Some sort of three way solid state relay I guess, with two bits of the parallel port dedicated to control. |
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#30
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Yes I see, your needs are simple. The difficult part would be converting to a
digital protocol. "MZ" wrote in message ... Ahhh, I think I misunderstood what you were trying to do. I thought you had some digital and some analog sources and wanted to switch between them. If you only need to switch analog sources I'd consider three digital volume control IC's. By controlling the volume of each with your PC you could implement a mixer. Most also incorporate a mute function on a seperate input pin which could come in handy. One to consider is the Texas Instruments PGA2310 with 120dB dynamic range and 0.0004% THD+N at 1kHz, and they are daisy chainable which means you need only one serial cable to control all three IC's. You could use the +/-12V from your PC to power it. http://focus.ti.com/lit/ds/sbos207b/sbos207b.pdf I'm sure there are many more solutions-on-a-chip with less features that would be easier to implement. They probably even have one with multiple input select. It's so easy to get carried away once you start looking. I believe this one would run you around $10 each but I'm sure TI would give you three samples. Actually, I don't think it will be necessary. Each of the devices has its own volume control. I'm not sure how they implement it, but as I mentioned in my last post, the radio device has a "radio volume" that is independent of the aux in volume control. So the software already controls the volume. What I need, however, is to be able to implement a switch between the three that can be controlled by the computer. Some sort of three way solid state relay I guess, with two bits of the parallel port dedicated to control. |
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#31
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speakers dont blow because of one thing...
You folks are debating weather a speaker blows because of too much power RMS WATTS its a combination of things.. the worst thing for a speaker coil is dc voltage... this occurs when clipping The best way to set your amplifier and headunit is to take a 1khz pure sine wave @ 0DB and adjust the head unit until clipping occurs (you will hear the difference) then adjust the gain on the amp for the same audible difference... bring them both down a hair and bam if you stay below those levels and your music is not over 0db (it shouldnt be because most cd's are recorded at -3 to 0db) then you shouldnt really be able to hurt or damage the speakers... over powering the speakers is a different story.. hyperextension is a problem that i had until i used my cutoff dials and removed some of the very low bass to my infinity kappa 572.5cf speakers kenny "MZ" wrote in message ... By putting 50 watts from any of the amps into the speaker you will not blow the speaker. However. with the smaller amp you at its rms limit. So program material with particularly loud bits in would send the signal over "50 watts" POSSIBLY causing the amplifier to clip. I agree. If you drive the 50 watt amp beyond 50 watts, then it's clipping. But this isn't the scenario he presented. Its this that will damage the speaker. Only if it's producing more than 100 watts. Remember, the scenario he presented was a 100 watt speaker. By definition, a 100 watt speaker is capable of handling 100 watts - otherwise, it's not a 100 watt speaker. This means that the 500 watt smplifier has more headroom (450 watts) before it will shows signs of clipping. This is above the rating of the loudspeaker anyway. Although with a rating of 100 watts you can safely put 200 watts thrugh it with normal program material. (just not a continuous signal like a sine wave), as program material, the music we listen to has loud parts and quiet parts. I understand the point you're trying to make. That is, that you can deliver a signal that has 200 watt transients to the 100 watt speaker without it blowing. That's because, on average, the signal is 100 watts or under. |
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#32
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speakers dont blow because of one thing...
You folks are debating weather a speaker blows because of too much power RMS WATTS its a combination of things.. the worst thing for a speaker coil is dc voltage... this occurs when clipping No it doesn't! Hook up a meter to a clipping amp and set it to record dc voltage. The reading will be zero. DC, by very definition, cannot alternate. That's called alternating current. Yes, the peaks are "flattened" when clipping. In fact, severe clipping can start to appear as a square wave. But a square wave has no DC component. It's purely an AC wave. A simple fourier transform of a square wave demonstrates this to be true. Sheesh, people. I've had to point this out for years. Don't you folks read the FAQ? |
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#33
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"Mercury" wrote in message . net... speakers dont blow because of one thing... That's right. There are two things that blow a speaker. Either exceeding it's mechanical limits or exceeding it's thermal limits. You folks are debating weather a speaker blows because of too much power RMS WATTS its a combination of things.. the worst thing for a speaker coil is dc voltage... this occurs when clipping There is absolutely no DC component when clipping. Show me the DC component in a clipped signal. And no it's not those flat parts of the wave, that is NOT DC. Clipping in and of itself will NOT blow speakers. The best way to set your amplifier and headunit is to take a 1khz pure sine wave @ 0DB and adjust the head unit until clipping occurs (you will hear the difference) then adjust the gain on the amp for the same audible difference... bring them both down a hair and bam if you stay below those levels and your music is not over 0db (it shouldnt be because most cd's are recorded at -3 to 0db) Why limit yourself to 0dB? If you do it this way then you limit your system to the point where it will just start getting loud at max and if you want more, well, you're screwed. If you get anything under 0db then your system will never get loud. With the varying recording levels, and with MP3 being so popular, it is wise to have headroom! A little something that your method does not allow for. then you shouldnt really be able to hurt or damage the speakers... over powering the speakers is a different story.. Over powering is not a different story. It's why most drivers fail. They are given more power than they can handle. No fancy tricks or gimmicks, it is plain and simple. hyperextension is a problem that i had until i used my cutoff dials and removed some of the very low bass to my infinity kappa 572.5cf speakers Over excursion, which is what I assume you are referring too, is a type of Mechanical failure. Les |
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#34
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alirght..... a better way of putting it.... at that instance of time
(where the amp or driver is clipping) it appears as DC, sure you can argue that with any AC wave as well... What i meant by DC is that the signal is flat and the coil is not moving the cone at that point.... this is bad for the coil because it heats up and the coil goes into thermal runaway... the coil heats up resistance goes up, requiring more voltage for the same output causing more heat... etc... you should get the picture.... some crappy amps when over driving actually get a DC offset weather it be positive or negitave this is very very bad for the coil.... You dont need to try and attack what i say... i assume you understod my "technilogical shortcuts" to explain something... next time I suppose I should drag in the fouriur transforms and differental equations... but i personally believe that is beyond the scope of this newsgroup. Believe me when I say i know what damages a coil, I deal with the three major components of electronics every day of my life... sometimes my oversimplifing of a subject gets me in trouble as you just witnessed... however the case may be... My point is that power does not damage the speaker in and of itself... over powering a speaker with good clean power will cause the cone to hyperextend and possibly cause the cone to rip therefore making a bad speaker... clipping or dc offsets for prolonged amounts of time will damage the coil therefore making a bad speaker... When i said DC i guess i should have been more specific... lets see if you agree with the following scenario: 20Hz = 20 cycles per second 1/F = 1/20 = period = .05 seconds for one postive and one negitive swing the signal is clipping at 50% of expected peak in both the positive and negitive direction just estimating.... since 1/2 of the positive and negitive signal is clipped that means that .025s out of .05s of the signal is damaging the voice coil... ideally... though in this case I am not so sure it will damage the coil that quickly... there is a happy medium to what the coil can take etc... by the way if you hook up a "good" meter to a dc square wave you can watch the dc on the meter toggle from positive to negitave... its all frequency dependent With your argument you would agree with this statement, "Reproducing square waves on a loudspeaker will not damage it" I would disagree 100 % with that because at low frequencies (where most people have clipping occuring because they are trying to pull every ounce of power to drive these huge woofers) square waves look more and more like DC (sure it toggles but the high time is a lot longer therefore damaging the coil....) The same can be said for a 1HZ sine wave... this is not good for a voice coil either... the coil is not made to move that slowly, not to mention we as humans cant hear 1Hz anyway. My point was to show that speakers can be damaged in more ways then one.... not to argue about how well or how poorly I explain myself... its clear to me you did not understand me the first time... I hope by writing this anecdote I was able to better get my point across... it was unfortunate i had to take up so much time and space to do it. Kenny "MZ" wrote in message ... speakers dont blow because of one thing... You folks are debating weather a speaker blows because of too much power RMS WATTS its a combination of things.. the worst thing for a speaker coil is dc voltage... this occurs when clipping No it doesn't! Hook up a meter to a clipping amp and set it to record dc voltage. The reading will be zero. DC, by very definition, cannot alternate. That's called alternating current. Yes, the peaks are "flattened" when clipping. In fact, severe clipping can start to appear as a square wave. But a square wave has no DC component. It's purely an AC wave. A simple fourier transform of a square wave demonstrates this to be true. Sheesh, people. I've had to point this out for years. Don't you folks read the FAQ? |
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#35
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"Les" wrote in message ... "Mercury" wrote in message . net... speakers dont blow because of one thing... That's right. There are two things that blow a speaker. Either exceeding it's mechanical limits or exceeding it's thermal limits. You folks are debating weather a speaker blows because of too much power RMS WATTS its a combination of things.. the worst thing for a speaker coil is dc voltage... this occurs when clipping There is absolutely no DC component when clipping. Show me the DC component in a clipped signal. And no it's not those flat parts of the wave, that is NOT DC. Clipping in and of itself will NOT blow speakers. It will if at a low enough frequency... ive done it The best way to set your amplifier and headunit is to take a 1khz pure sine wave @ 0DB and adjust the head unit until clipping occurs (you will hear the difference) then adjust the gain on the amp for the same audible difference... bring them both down a hair and bam if you stay below those levels and your music is not over 0db (it shouldnt be because most cd's are recorded at -3 to 0db) Why limit yourself to 0dB? If you do it this way then you limit your system to the point where it will just start getting loud at max and if you want more, well, you're screwed. so you tell us... im interested... do i make a sine wave at 3db that way when i get a cd thats recorded at 0db or -3 db it will sound so far off and distant i can barely hear it? if i inject a -3 or -6 db sine wave and adjust to it when i get a +3db or 0 db song then it will clip... i perfect it not to clip... not only does it hurt the speakers but it sounds like crap as well If you get anything under 0db then your system will never get loud. With the varying recording levels, and with MP3 being so popular, it is wise to have headroom! A little something that your method does not allow for. then you shouldnt really be able to hurt or damage the speakers... over powering the speakers is a different story.. Over powering is not a different story. It's why most drivers fail. They are given more power than they can handle. No fancy tricks or gimmicks, it is plain and simple. so with 100W speakers and a 100W amplifier how is it possible that the speaker can be damaged? if clipping does not afftect the speaker... the speaker in this case may be damaged due to DC offset hyperextension is a problem that i had until i used my cutoff dials and removed some of the very low bass to my infinity kappa 572.5cf speakers Over excursion, which is what I assume you are referring too, is a type of Mechanical failure. you call it po-tato i call it patato... same differnce its not a mechancial failure its called overpowering the speaker at that frequency range.... if it had less power to it it would not hyper extend would it? Kenny Les |
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#36
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alirght..... a better way of putting it.... at that instance of time
(where the amp or driver is clipping) it appears as DC, sure you can argue that with any AC wave as well... Thanks for clarifying your position. What i meant by DC is that the signal is flat and the coil is not moving the cone at that point.... Not true. See my reply earlier in this thread. In short, the coil's inductance prevents it from standing still. this is bad for the coil because it heats up and the coil goes into thermal runaway... the coil heats up resistance goes up, requiring more voltage for the same output causing more heat... etc... you should get the picture.... Um...thermal runaway isn't at play. In fact, what you described is the opposite of thermal runaway - rather, it would be a negative feedback mechanism. some crappy amps when over driving actually get a DC offset weather it be positive or negitave this is very very bad for the coil.... Faulty amps can. But I know of no amplifier, not even the cheapest amp on the market, that has a significant DC offset. If there was, the company would go out of business as the result of a class action suit. You dont need to try and attack what i say... i assume you understod my "technilogical shortcuts" to explain something... next time I suppose I should drag in the fouriur transforms and differental equations... but i personally believe that is beyond the scope of this newsgroup. I think you're insulting the intelligence of the regular readers of this newsgroup. Sure, differential equations aren't necessary, but valid logic and sound scientific principles are. The notion that you first presented (that DC is being delivered to the speaker) turned out to be wrong. Then your insistence that the coil actually stops moving turned out to be wrong. It's not beyond the scope of this newsgroup to present factual information. Believe me when I say i know what damages a coil, I deal with the three major components of electronics every day of my life... sometimes my oversimplifing of a subject gets me in trouble as you just witnessed... however the case may be... My point is that power does not damage the speaker in and of itself... over powering a speaker with good clean power will cause the cone to hyperextend and possibly cause the cone to rip therefore making a bad speaker... clipping or dc offsets for prolonged amounts of time will damage the coil therefore making a bad speaker... But you've yet to supply a valid reason WHY you think that clipping will damage a coil. First you said it's DC. Nope. Then you said the coil stands still. Nope. So, please, try again. When i said DC i guess i should have been more specific... lets see if you agree with the following scenario: 20Hz = 20 cycles per second 1/F = 1/20 = period = .05 seconds for one postive and one negitive swing the signal is clipping at 50% of expected peak in both the positive and negitive direction just estimating.... since 1/2 of the positive and negitive signal is clipped that means that .025s out of .05s of the signal is damaging the voice coil... ideally... though in this case I am not so sure it will damage the coil that quickly... there is a happy medium to what the coil can take etc... Yes. Now take a look at the spectral content of the 20Hz clipped signal (by the way, you won't clip at 20 Hz if you're listening to music - the spectral content is not high enough!). Then recognize that a voice coil is nothing more than an inductor, and therefore has an inductance. That means it's a low pass filter! That's why subwoofers have a high impedance at high frequencies. So, if the subwoofer is electrically filtering out the high frequency portions of the clipped wave, and it's also mechanically filtering out high frequencies (I'll describe this as well, if you want), then the flat peaks are becoming rounded. If you're unfamiliar with what low pass filtering does to a square wave, then I can see how you'd overlook this. by the way if you hook up a "good" meter to a dc square wave you can watch the dc on the meter toggle from positive to negitave... its all frequency dependent Um...no, a needle isn't going to toggle tens or hundreds of times per second. It too has an inductance (which is how the coil works actually!). With your argument you would agree with this statement, "Reproducing square waves on a loudspeaker will not damage it" No, I'd say "you can't reproduce a square wave with a subwoofer". If you're talking about tweeters, or some midrange speakers, then yes I'd agree with that statement. Tell me what it is about a square wave that's inherently damaging. I would disagree 100 % with that because at low frequencies (where most people have clipping occuring because they are trying to pull every ounce of power to drive these huge woofers) square waves look more and more like DC (sure it toggles but the high time is a lot longer therefore damaging the coil....) Actually, this is wrong. As I'm sure you know, a square wave is nothing but a combination of sine waves. So a 20Hz square wave is EQUIVALENT to a 20Hz sine wave, plus a 60Hz sine wave of 1/3 amplitude, plus a 100Hz sine wave of 1/5 amplitude, and so on. This is what fourier analysis gives you, even though you'd prefer to ignore it. So, in fact, square waves incorporate higher frequency components than their single sine wave counterparts. The same can be said for a 1HZ sine wave... this is not good for a voice coil either... the coil is not made to move that slowly, not to mention we as humans cant hear 1Hz anyway. Yeah, so why are you bringing up 1Hz sine waves? My point was to show that speakers can be damaged in more ways then one.... You're right. They can. They can be damaged thermally or mechanically. Clipping does not change this. It won't cause the speaker to heat up any faster and it won't cause it to exceed its maximum excursion. not to argue about how well or how poorly I explain myself... its clear to me you did not understand me the first time... I hope by writing this anecdote I was able to better get my point across... it was unfortunate i had to take up so much time and space to do it. You've done a fine job explaining yourself now. I think you're just up against some misconceptions that you need to rid yourself of. The first is that a square wave DOES NOT contain a DC component. This can easily be proven. It's not a matter of opinion. The second is your idea that the coil actually stops moving. But basic electrical theory demonstrates that this doesn't happen - look up the inductance of a typical subwoofer coil in the T/S parameters of a driver and note that it acts as a low pass filter. Then look at what happens to the "flat tops" of a wave when you filter it. Hope this helps. |
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#37
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"Mercury" wrote in message . net... alirght..... a better way of putting it.... at that instance of time (where the amp or driver is clipping) it appears as DC, sure you can argue that with any AC wave as well... It's not arguing that it's AC, it IS AC. There is no DC component. What i meant by DC is that the signal is flat and the coil is not moving the cone at that point.... 2 things, the flat signal is NOT DC and the cone never stops moving. You cannot have alternating DC, it just does not work that way. Clipped wave, square wave, it doesn't matter. By the mere fact you are calling it a wave implies AC. this is bad for the coil because it heats up and the coil goes into thermal runaway... You act like the motion of the coil is the only cooling factor, but it's not. Material choices, convection, air gaps, etc all play a factor as well. But nonetheless it doesn't matter because the way thermally destroy a speaker is to give it too much power. the coil heats up resistance goes up, If the resistance went up the there would be less power that can be delievered which would serve in cooling the driver. requiring more voltage for the same output causing more heat... etc... The amp would have to work harder, but the speaker really wouldn't care. you should get the picture.... some crappy amps when over driving actually get a DC offset weather it be positive or negitave this is very very bad for the coil.... I have never seen a properly functioning amplifier, whether cheap or expensive, that had a DC offset. If it has DC then the amp is broken. Try and keep the discussion to relevant amplifiers and not something that belongs in the repair bin. You dont need to try and attack what i say... i assume you understod my "technilogical shortcuts" to explain something... I understood them, but they are wrong. next time I suppose I should drag in the fouriur transforms and differental equations... but i personally believe that is beyond the scope of this newsgroup. It is well within the realms of this newsgroup, it is related to car audio after all. But I suspect the real reason is that you have no idea what it is you just wrote and that's why it is "out of the scope". Believe me when I say i know what damages a coil, Demonstrate that you know BASIC concepts of how a speaker and amplifier work and someone just might. Do you really think alternating DC makes sense? I deal with the three major components of electronics every day of my life... sometimes my oversimplifing of a subject gets me in trouble as you just witnessed... however the case may be... My point is that power does not damage the speaker in and of itself... What? I am definantly putting that one in the book of "most asinine comment". Power is EXACTLY how you blow a speaker. Very plain, very simple. Surpass the drivers power ratings and soon you will have one very toasty speaker. over powering a speaker with good clean power will cause the cone to hyperextend and possibly cause the cone to rip therefore making a bad speaker... It could..... if you are actually playing frequencies that could do that. But that is a limited part of the frequency spectrum. I can make the cone "hyperextend" with a square wave too. So what really did the damage? clipping or dc offsets for prolonged amounts of time will damage the coil therefore making a bad speaker... Clipping will not make for a bad speaker. The speaker could really care less, it doesn't know. by the way if you hook up a "good" meter to a dc square wave you can watch the dc on the meter toggle from positive to negitave... its all frequency dependent What meter are you using? With your argument you would agree with this statement, "Reproducing square waves on a loudspeaker will not damage it" If you don't exceed the power limits then yes I would agree with that. I would disagree 100 % with that And this is why you are wrong. because at low frequencies (where most people have clipping occuring because they are trying to pull every ounce of power to drive these huge woofers) square waves look more and more like DC Do you know what DC looks like? Let me draw it for you. __________________________________________________ __ There you go. (Ok that was one of my shortcuts cause it's late) Notice, there is no alternating. It is crucial. And just because something resembles DC doesn't mean that it IS DC. Legacy amps look more and more like Sony as time goes on, does that mean they are a sony amp? No. Same thing here. (sure it toggles but the high time is a lot longer therefore damaging the coil....) The same can be said for a 1HZ sine wave... this is not good for a voice coil either... the coil is not made to move that slowly, not to mention we as humans cant hear 1Hz anyway. My point was to show that speakers can be damaged in more ways then one.... Yep, there's 2. Which I pointed out in my other post. not to argue about how well or how poorly I explain myself... its clear to me you did not understand me the first time... I hope by writing this anecdote I was able to better get my point across... it was unfortunate i had to take up so much time and space to do it. Your point was clear the first time Kenny. The problem is that your point is based on illogical arguments and fallable thinking. The very core of your argument is asinine, and wrong, therefore the rest just builds on wrong answers. |
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#38
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"Sm704" wrote in message m... Can playing a song that has distortion in it cause damage to speakers? I don't mean the equipment itself causing the distortion, but distortion in the recording itself. For example, Neil Young's "Hey Hey, My My (Into the Black)" is a good example of a song with distortion. Another one I can think of would be "Revolution" by the Beatles. Would playing either of these songs loudly cause damage to speakers? Thanks Providing you are within the limits of your equipment..... NO  just incase you had forgotten the original post. |
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#39
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take a very very low frequency clipping sine wave and power the speaker with
it.... I dare you to tell me it wont damage it, the reason it gets damaged is that the wave spends too much time on one side of 0 (DC) at low frequencies it is a varying DC wave until that wave crosses 0 then it can be called an AC wave.... I see where people come up with the thought that I have fallible thinking.. maybe i do.. thats why im here to maybe fix that So tell me why its so important for people not to clip? I play some loud music... its ok for me to blast it? even if its clipping? It just wont sound as good.... By the way give the speaker an ac sine wave at a low frequency that is clipping and I dare you to proce the cone doesnt move... at that time it is like pure DC at one Level the most extreme case take 1Hz or .5Hz or heck.... .1Hz now tell me that doesnt damage a speaker and ill gladly walk away laughing A good meter is what i used a fluke 87 on DC mode you can watch it toggle any time the frequency is less then about 50 - 60hz It toggles too quickly to get a reading of course.... but it does toggle to get the average dc value a needle meter should be hooked up and the average of the deflection should be 0.... try it with a digital it doesnt work as well until you get a high enough frequency I suppose my points may be fallible i admit it.. But tell me why severe clipping is ok for a speaker then I can power my speakers more without damaging themn Also please do tell how to set up a head unit and amplifier to make so i dont over power my speakers I am using an alpine MRV-540F 100W X 4 rms output i am using infinty kappa 100W 5x7 speakers using a sony mp3 player.... as a head unit whats the best way to set up the headunit and the amp... i can use the sine wave until it distorts again just tell me how to make the signal using cooledit... thats what i use.. tell me its charecteristics... frequency, amplitude etc... Thanks, Ken "Les" wrote in message ... "Mercury" wrote in message . net... alirght..... a better way of putting it.... at that instance of time (where the amp or driver is clipping) it appears as DC, sure you can argue that with any AC wave as well... It's not arguing that it's AC, it IS AC. There is no DC component. What i meant by DC is that the signal is flat and the coil is not moving the cone at that point.... 2 things, the flat signal is NOT DC and the cone never stops moving. You cannot have alternating DC, it just does not work that way. Clipped wave, square wave, it doesn't matter. By the mere fact you are calling it a wave implies AC. this is bad for the coil because it heats up and the coil goes into thermal runaway... You act like the motion of the coil is the only cooling factor, but it's not. Material choices, convection, air gaps, etc all play a factor as well. But nonetheless it doesn't matter because the way thermally destroy a speaker is to give it too much power. the coil heats up resistance goes up, If the resistance went up the there would be less power that can be delievered which would serve in cooling the driver. requiring more voltage for the same output causing more heat... etc... The amp would have to work harder, but the speaker really wouldn't care. you should get the picture.... some crappy amps when over driving actually get a DC offset weather it be positive or negitave this is very very bad for the coil.... I have never seen a properly functioning amplifier, whether cheap or expensive, that had a DC offset. If it has DC then the amp is broken. Try and keep the discussion to relevant amplifiers and not something that belongs in the repair bin. You dont need to try and attack what i say... i assume you understod my "technilogical shortcuts" to explain something... I understood them, but they are wrong. next time I suppose I should drag in the fouriur transforms and differental equations... but i personally believe that is beyond the scope of this newsgroup. It is well within the realms of this newsgroup, it is related to car audio after all. But I suspect the real reason is that you have no idea what it is you just wrote and that's why it is "out of the scope". Believe me when I say i know what damages a coil, Demonstrate that you know BASIC concepts of how a speaker and amplifier work and someone just might. Do you really think alternating DC makes sense? I deal with the three major components of electronics every day of my life... sometimes my oversimplifing of a subject gets me in trouble as you just witnessed... however the case may be... My point is that power does not damage the speaker in and of itself... What? I am definantly putting that one in the book of "most asinine comment". Power is EXACTLY how you blow a speaker. Very plain, very simple. Surpass the drivers power ratings and soon you will have one very toasty speaker. over powering a speaker with good clean power will cause the cone to hyperextend and possibly cause the cone to rip therefore making a bad speaker... It could..... if you are actually playing frequencies that could do that. But that is a limited part of the frequency spectrum. I can make the cone "hyperextend" with a square wave too. So what really did the damage? clipping or dc offsets for prolonged amounts of time will damage the coil therefore making a bad speaker... Clipping will not make for a bad speaker. The speaker could really care less, it doesn't know. by the way if you hook up a "good" meter to a dc square wave you can watch the dc on the meter toggle from positive to negitave... its all frequency dependent What meter are you using? With your argument you would agree with this statement, "Reproducing square waves on a loudspeaker will not damage it" If you don't exceed the power limits then yes I would agree with that. I would disagree 100 % with that And this is why you are wrong. because at low frequencies (where most people have clipping occuring because they are trying to pull every ounce of power to drive these huge woofers) square waves look more and more like DC Do you know what DC looks like? Let me draw it for you. __________________________________________________ __ There you go. (Ok that was one of my shortcuts cause it's late) Notice, there is no alternating. It is crucial. And just because something resembles DC doesn't mean that it IS DC. Legacy amps look more and more like Sony as time goes on, does that mean they are a sony amp? No. Same thing here. (sure it toggles but the high time is a lot longer therefore damaging the coil....) The same can be said for a 1HZ sine wave... this is not good for a voice coil either... the coil is not made to move that slowly, not to mention we as humans cant hear 1Hz anyway. My point was to show that speakers can be damaged in more ways then one.... Yep, there's 2. Which I pointed out in my other post. not to argue about how well or how poorly I explain myself... its clear to me you did not understand me the first time... I hope by writing this anecdote I was able to better get my point across... it was unfortunate i had to take up so much time and space to do it. Your point was clear the first time Kenny. The problem is that your point is based on illogical arguments and fallable thinking. The very core of your argument is asinine, and wrong, therefore the rest just builds on wrong answers. |
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#40
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take a very very low frequency clipping sine wave and power the speaker
with it.... If by "very very low frequency" you mean around 1Hz, as your earlier example mentioned, then it doesn't matter whether or not the wave is clipping. It's still going to impede the air flow dynamic. But why do you insist on bringing up examples that have no basis in the real world? I dare you to tell me it wont damage it, the reason it gets damaged is that the wave spends too much time on one side of 0 (DC) Who cares if it spends too much time on one side? It's really not as devastating as you would think. In fact, it may be BETTER that it's clipped because then forced air convection becomes a bigger factor by actively pushing air into and out of the gap, whereas a 1Hz sine wave doesn't do this all too well. And if the excursion of the voice coil is not greater than the voice coil length, the dispersion of heat over a given area will be wider also under the clipped condition than under the sine condition. In short, I wouldn't be surprised in the least if the 1Hz sine wave blew the speaker before the 1Hz square wave did. at low frequencies it is a varying DC wave until that wave crosses 0 then it can be called an AC wave.... "DC wave" is an oxymoron. It's either AC or DC. You can't selectively pick a part of a wave and say it's DC. The FACT (again, this is fact, not opinion - and it can be backed by any introductory electronics textbook) is that a square wave is an AC wave with no DC component to it. I see where people come up with the thought that I have fallible thinking.. maybe i do.. thats why im here to maybe fix that So tell me why its so important for people not to clip? This has been covered in great detail in this newsgroup. Do a google search. In short, clipping does two things: 1) it increases the overall power content of the signal; and 2) it introduces high frequency harmonics which therefore increases the power content of the high frequency portion. Note that both reasons for concern have to do with excess power. So, a 50 watt amp can actually theoretically produce 100 watts (the power content of a square wave is double that of a sine wave) when fully clipped. It never quite gets to 100 watts because of the output impedance of the amplifier, but it's important to recognize that the power does in fact increase. Tweeters are especially prone to being blown when clipping because this increase in power tends to reside in the higher frequency portions of the spectrum, because as I pointed out earlier, a square wave is composed of a fundamental frequency and a series of odd-order harmonics. A good meter is what i used a fluke 87 on DC mode you can watch it toggle any time the frequency is less then about 50 - 60hz It toggles too quickly to get a reading of course.... but it does toggle to get the average dc value There is no such thing as an "average DC value". If the value is varying such that you need to take the average, then it's AC by definition. I think you need to pick up a physics textbook so you can see how AC and DC are defined. Also please do tell how to set up a head unit and amplifier to make so i dont over power my speakers I am using an alpine MRV-540F 100W X 4 rms output i am using infinty kappa 100W 5x7 speakers using a sony mp3 player.... as a head unit whats the best way to set up the headunit and the amp... i can use the sine wave until it distorts again just tell me how to make the signal using cooledit... thats what i use.. I wouldn't use Cool Edit to do it. Use your ears and a couple CDs. You need to set the gain so that you can listen to the quietest CD you own at full output power. As you can see, if you use a 0dB signal to set the gains, then you'll never be able to get your quiet CDs to play at full volume. |
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