Home |
Search |
Today's Posts |
#1
|
|||
|
|||
would this phase correction idea work?
hello everyone,
let's say you 2-miked an instrument and recorded it as a stereo file into the DAW. then when you listened back, you thought it sounded out of phase. would it make sense to simply de-couple the stereo file in a wave editor and then nudge one of the left or right tracks a few samples to get it in phase? |
#2
|
|||
|
|||
an easier route would be to usa a program like audition or pro tools or
anything and use a phase canceler/converter/changer/whatever plugin to adjust the phase and just move the slider a little and listen. i would personally use the phase analysis tool in audition as it will tell you to an extreme degree of accuracy wether the tracks are in phase or not. they may also be 180 degrees out of phase as thworing may have been mixed up somewhere alon your signal path. try inverting one of the tracks to see what happens. i would not try to manually change the phase as your soundcard is probably not good enough to be sample accurate and differentiate the differance if a sound file is ten samples delayed or something, did that make sense? whatever. give it a shot. |
#3
|
|||
|
|||
something i forgot to soay is that if you 'nudge' the file at all you
will be adding delay to the track introducing a possible flanger type effect, ugly. |
#4
|
|||
|
|||
No ! The result will not be mono compatible.
And it will only work if the sound is one single frequency. There is a difference between electrical phase and temporal (time, for you earthlings) displacement. If the 'phase' problem was created by latency then yes - you correct the difference by slipping one file to line up with the other. If the problem is one side electrically "out of phase" then the entire right (or left) channel needs inverted (polarity) but not slipped in the time domain. rd |
#6
|
|||
|
|||
Assuming that the temporal delay was entirely due to distance from the
speaker in question, why would this not be the exact same thing as latency? tak On 2005-01-11 02:26:52 -0500, "RD Jones" said: No ! The result will not be mono compatible. And it will only work if the sound is one single frequency. There is a difference between electrical phase and temporal (time, for you earthlings) displacement. If the 'phase' problem was created by latency then yes - you correct the difference by slipping one file to line up with the other. If the problem is one side electrically "out of phase" then the entire right (or left) channel needs inverted (polarity) but not slipped in the time domain. rd |
#7
|
|||
|
|||
Takeshi Yama****a wrote: Assuming that the temporal delay was entirely due to distance from the speaker in question, why would this not be the exact same thing as latency? tak If the 'phase' issue is due to time delay from differing distance, then the effect is similar to that of latency. But slipping the 2 back into phase with each other will create it's own effect. Are the 2 signals both centered and at the same level ? Better to lower the level of the secondary (delayed) signal until the phase effect is reduced, or better yet: Center or near center the first arriving signal, and hard or far pan the secondary signal. Hendrix used this effect and I like his work. The question is what's causing the phasing sound latency/time issues or electrical polarity ? And is it objectionable ? rd |
#8
|
|||
|
|||
wrote in message
ups.com hello everyone, let's say you 2-miked an instrument and recorded it as a stereo file into the DAW. then when you listened back, you thought it sounded out of phase. would it make sense to simply de-couple the stereo file in a wave editor and then nudge one of the left or right tracks a few samples to get it in phase? No, you'd just invert the phase of either of the channels. |
#9
|
|||
|
|||
Well, the problem is if you "just invert the phase of either of the
channels" and then listened back in mono, the channels would cancel each other out and you would end up with a very thin sound. If you're listening back to the track in the context of the whole mix, it will probably sound like it just dissappeared! If you can re-record it, that's the better alternative. If you can't, then try any of the suggestions you've gotten here and make sure you go back and forth between mono and stereo to see how the sound changes. You should always do a stereo/mono comparison flipping back and forth when recording any stereo track . If you are going to re-record it, there's an easy way to make the mics more in phase with each other - While positioning the mics, flip one side out of phase, listen in mono, start with no EQ or effects on either and get a good solid sound with your first mic. Then with the second mic, find the position where the sound cancels the most or sounds the thinnest. The closer you are micing, the more pronounced the effect will be. Then ,flip the out of phase side back into phase and do your mono/stereo comparison. This also works better if the mics are closely matched. This technique also works great when recording bass using a mic and a direct box. Start with the direct sound and then, starting about an inch away from the speaker, move the out of phase mic away from the speaker until the sound almost completely cancels and then flip it back into phase. This will get you the strongest signal. Since bass is almost always in mono it can mean the difference between a solid or a weak bass sound - and of course - a weak bass sound means a weak mix! |
#10
|
|||
|
|||
Well, the problem is if you "just invert the phase of either of the
channels" and then listened back in mono, the channels would cancel each other out and you would end up with a very thin sound. If you're listening back to the track in the context of the whole mix, it will probably sound like it just dissappeared! If you can re-record it, that's the better alternative. If you can't, then try any of the suggestions you've gotten here and make sure you go back and forth between mono and stereo to see how the sound changes. You should always do a stereo/mono comparison flipping back and forth when recording any stereo track . If you are going to re-record it, there's an easy way to make the mics more in phase with each other - While positioning the mics, flip one side out of phase, listen in mono, start with no EQ or effects on either and get a good solid sound with your first mic. Then with the second mic, find the position where the sound cancels the most or sounds the thinnest. The closer you are micing, the more pronounced the effect will be. Then ,flip the out of phase side back into phase and do your mono/stereo comparison. This also works better if the mics are closely matched. This technique also works great when recording bass using a mic and a direct box. Start with the direct sound and then, starting about an inch away from the speaker, move the out of phase mic away from the speaker until the sound almost completely cancels and then flip it back into phase. This will get you the strongest signal. Since bass is almost always in mono it can mean the difference between a solid or a weak bass sound - and of course - a weak bass sound means a weak mix! |
#11
|
|||
|
|||
If it sounds "out of phase," the error is a heck of a lot greater than nudging
one channel a few samples can fix. Are the mics the same model? Are they the same distance from the instrument? Is there a possibility of polarity inversion somewhere in the chain? |
#13
|
|||
|
|||
One more thing you might try that hasn't been suggested yet - Just use
the one side you like best and send it through a stereo plug-in or reamp it out to an amp and mic it. And of course, as always, do the mono/stereo comparison to check the integrity of your signal. |
#14
|
|||
|
|||
hello everyone, let's say you 2-miked an instrument and recorded it as a stereo file into the DAW. then when you listened back, you thought it sounded out of phase. would it make sense to simply de-couple the stereo file in a wave editor and then nudge one of the left or right tracks a few samples to get it in phase? Yes, that will work for a PHASE problem. It will not work on a POLARITY problem. Phase involves time and polarity does not. If you have a polarity problem, simply invert one of the files. Richard H. Kuschel "I canna change the law of physics."-----Scotty |
#15
|
|||
|
|||
wrote in message
oups.com ] Well, the problem is if you "just invert the phase of either of the channels" and then listened back in mono, the channels would cancel each other out and you would end up with a very thin sound. If you're listening back to the track in the context of the whole mix, it will probably sound like it just dissappeared! I'm keying off the OP, which said "let's say you 2-miked an instrument and recorded it as a stereo file into the DAW. then when you listened back, you thought it sounded out of phase." I'm presuming that somehow polarity got flipped during the recording process. That's what the post says to me. |
#16
|
|||
|
|||
A "flanger" effect would be a delay but a varying length of delay, i.e.
an "out of phase" pair of signals that change their phase relationship over time. Unfortunately, what arrived at the two microphones is a complex picture of the instrument, and moving the two mics in a time relationship to each other will not likely fix the problem. However, subjectively, the sound may improve, although I doubt it. It may be the case, as someone else pointed out, that simply changing the polarity of one of the mics may make the most improvement (if one of the mics was out of polarity in the first place). Phase and group delay are not necessarily interchangeable... Karl Winkler Lectrosonics, Inc. http://www.lectrosonics.com |
#17
|
|||
|
|||
On Tue, 11 Jan 2005 01:49:11 -0500, wrote
(in article . com): hello everyone, let's say you 2-miked an instrument and recorded it as a stereo file into the DAW. then when you listened back, you thought it sounded out of phase. would it make sense to simply de-couple the stereo file in a wave editor and then nudge one of the left or right tracks a few samples to get it in phase? absolutely. Ty Ford -- Ty Ford's equipment reviews, audio samples, rates and other audiocentric stuff are at www.tyford.com |
#18
|
|||
|
|||
would it make sense to simply de-couple the stereo file in a wave
editor and then nudge one of the left or right tracks a few samples to get it in phase? BRBR Yes. For that reason, I typically record stereo sources to dual mono tracks. Once I've slipped the tracks until I'm happy I lock them as stereo. Joe Egan EMP Colchester, VT www.eganmedia.com |
#19
|
|||
|
|||
On 11 Jan 2005 05:17:27 -0800, wrote:
Well, the problem is if you "just invert the phase of either of the channels" and then listened back in mono, the channels would cancel each other out and you would end up with a very thin sound. If you're listening back to the track in the context of the whole mix, it will probably sound like it just dissappeared! But he think's the problem may be due to one mic being out of phase in the first place. CubaseFAQ www.laurencepayne.co.uk/CubaseFAQ.htm "Possibly the world's least impressive web site": George Perfect |
#20
|
|||
|
|||
Laurence Payne wrote:
On 11 Jan 2005 05:17:27 -0800, wrote: Well, the problem is if you "just invert the phase of either of the channels" and then listened back in mono, the channels would cancel each other out and you would end up with a very thin sound. If you're listening back to the track in the context of the whole mix, it will probably sound like it just dissappeared! But he think's the problem may be due to one mic being out of phase in the first place. Then call it "reversed polarity," which is what it is, and not "out of phase" which is a general phrase that can encompass a whole lot of unrelated things. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#21
|
|||
|
|||
"Scott Dorsey" wrote in message
Laurence Payne wrote: On 11 Jan 2005 05:17:27 -0800, wrote: Well, the problem is if you "just invert the phase of either of the channels" and then listened back in mono, the channels would cancel each other out and you would end up with a very thin sound. If you're listening back to the track in the context of the whole mix, it will probably sound like it just disappeared! But he think's the problem may be due to one mic being out of phase in the first place. Then call it "reversed polarity," which is what it is, and not "out of phase" which is a general phrase that can encompass a whole lot of unrelated things. I didn't call it "out of phase" which I agree can be vague and can be easy to misunderstand. I said "invert the phase" which has a pretty unique meaning in most places. We all seem to know that the problem I was addressing was polarity. Furthermore, the meaning of the phrase "invert the phase" was even correctly deduced by the person who took exception to my suggestion. So, let's review: I knew what I meant and everybody who read it seems to know what I meant. Leaves only one question - where's the beef? |
#22
|
|||
|
|||
would it make sense to simply de-couple the stereo file in a wave
editor and then nudge one of the left or right tracks a few samples to get it in phase? Yes, you can do that. Or alternatively you could try one of the allpass filters available in a plugin form. http://www.voxengo.com/pha979/ Mark "In this business egos can be wonderful, but they also can be a curse." Michael Wagener |
#23
|
|||
|
|||
No ! The result will not be mono compatible.
Don't ya just love Usenet. bg Mark "In this business egos can be wonderful, but they also can be a curse." Michael Wagener |
#24
|
|||
|
|||
"Ty Ford" wrote in message
On Tue, 11 Jan 2005 01:49:11 -0500, wrote (in article . com): hello everyone, let's say you 2-miked an instrument and recorded it as a stereo file into the DAW. then when you listened back, you thought it sounded out of phase. would it make sense to simply de-couple the stereo file in a wave editor and then nudge one of the left or right tracks a few samples to get it in phase? absolutely. I don't think so. If you want to de-couple tracks enough to make a difference, you need to nudge them many milliseconds. You want them to be far enough apart so that they sound different from each other, but not far enough to create an audible echo. |
#26
|
|||
|
|||
|
#27
|
|||
|
|||
|
#28
|
|||
|
|||
|
#29
|
|||
|
|||
I don't think so. If you want to de-couple tracks enough to make a
difference, you need to nudge them many milliseconds. Not at all. A nudge of a millesecond or less can result in a substantial timbre shift. Scott Fraser |
#30
|
|||
|
|||
"ScotFraser" wrote in message
I don't think so. If you want to de-couple tracks enough to make a difference, you need to nudge them many milliseconds. Not at all. A nudge of a millesecond or less can result in a substantial timbre shift. Sure, massive comb filter effects. Is that the best way to deal with the issue? |
#31
|
|||
|
|||
wrote:
let's say you 2-miked an instrument and recorded it as a stereo file into the DAW. then when you listened back, you thought it sounded out of phase. Why should it? - what possible cause is it that you have in mind? Also: You ask about delay, not about phase. Phase unlinearity is about different delay time in different frequency ranges, which is why it is compensated - if relevant, it was relevant for analog tape recording, but hardly ever done, and it was relevant for example for the Sony PCM F1, in which context I have heard it cause amazing improvement - with a circuit called an all pass filter. would it make sense to simply de-couple the stereo file in a wave editor and then nudge one of the left or right tracks a few samples to get it in phase? Allow me to label that an "advanced stereo modification to be used with great caution by highly skilled operators". It is possible to slightly alter the "midline axis" of the sound from a valid stereo mic setup by doing what you suggest, but that is a very different concept. I have done it twice: with a chamber music recording of a piano trio that placed themselves somewhat different from what was assumed in the mic placement and with a mandolin and guitar ensemble that was asymmetrically positioned on a bar scene to focus their sound in the direction of the majority of the audience. The indication for doing was with both recordings a perceived inbalance that could not be compensated with a simple level change. This was not about something that sounded "partially out of phase". The proper thing to do is generally to position the mic pair correctly, delaying one channel relative to the other is a potential cause of more problems than it solves and mono compatibility is certainly a major worry to consider. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#32
|
|||
|
|||
Laurence Payne wrote:
If you feel one mic was closer than the other, a simple delay may help. Look at the waveforms at high magnification and nudge one until they align. It is not *that* simple - it would be if it was a recording in a sound dead room, but it isn't - listening is also required and what is perceived right may not "look right". Great caution is adviced ..... including listening on several loudspeaker setups. CubaseFAQ www.laurencepayne.co.uk/CubaseFAQ.htm Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#33
|
|||
|
|||
Laurence Payne wrote:
On 11 Jan 2005 05:17:27 -0800, wrote: Well, the problem is if you "just invert the phase of either of the channels" and then listened back in mono, the channels would cancel each other out and you would end up with a very thin sound. If you're listening back to the track in the context of the whole mix, it will probably sound like it just dissappeared! But he think's the problem may be due to one mic being out of phase in the first place. In which case the fix is to reverse the polarity of the inversed channel, it can not be addressed in any other way. It may be possible to determine which channel that has been inverted with some, but not perfect, assurance if the recorded signal is naturally asymmetric. CubaseFAQ www.laurencepayne.co.uk/CubaseFAQ.htm "Possibly the world's least impressive web site": George Perfect Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#34
|
|||
|
|||
siguy wrote:
an easier route would be to usa a program like audition or pro tools or anything and use a phase canceler/converter/changer/whatever plugin to adjust the phase and just move the slider a little and listen. i would personally use the phase analysis tool in audition as it will tell you to an extreme degree of accuracy wether the tracks are in phase or not. they may also be 180 degrees out of phase as thworing may have been mixed up somewhere alon your signal path. ....snip.. Hmmm, this has me wondering: What phase analysis tools are out there in common use? For that matter, are there any good articles or books that address phase issues in modern audio work [i.e.: radio, live sound, mastering etc.] ? I'd like to learn a bit more on the subject, both theory and applied. Later... Ron Capik -- |
#35
|
|||
|
|||
Ron Capik wrote:
Hmmm, this has me wondering: What phase analysis tools are out there in common use? Soundcraft's small B100 and BVE100 broadcast mixers have an onboard phase meter. rd |
#36
|
|||
|
|||
RD Jones wrote:
Ron Capik wrote: Hmmm, this has me wondering: What phase analysis tools are out there in common use? Soundcraft's small B100 and BVE100 broadcast mixers have an onboard phase meter. Yes, and there are a lot of the outboard meters like the Dorrough and RTW meters that have basic phase metering. I never found these to be all that useful, though. They don't really tell you anything that mono summing doesn't tell you, and they aren't any help for getting a sense of stereo imaging in bad monitoring situations. An X-Y display like the Tektronix audio monitor is very useful for getting a sense of stereo imaging when you can't trust your monitors, and it can be very handy for broadcast and record-cutting work where the sum and difference channels are asymmetric. But you very seldom see them any longer. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#37
|
|||
|
|||
On Tue, 11 Jan 2005 11:34:52 -0500, Arny Krueger wrote
(in article ): "Ty Ford" wrote in message On Tue, 11 Jan 2005 01:49:11 -0500, wrote (in article . com): hello everyone, let's say you 2-miked an instrument and recorded it as a stereo file into the DAW. then when you listened back, you thought it sounded out of phase. would it make sense to simply de-couple the stereo file in a wave editor and then nudge one of the left or right tracks a few samples to get it in phase? absolutely. I don't think so. If you want to de-couple tracks enough to make a difference, you need to nudge them many milliseconds. You want them to be far enough apart so that they sound different from each other, but not far enough to create an audible echo. I do it in Pro Tools all the time. It's quite easy to zoom in and align the wave forms. Correcting for mic distances or azimuth errors is a snap. Smiles, Ty Ford -- Ty Ford's equipment reviews, audio samples, rates and other audiocentric stuff are at www.tyford.com |
#38
|
|||
|
|||
Scott Dorsey wrote:
RD Jones wrote: Ron Capik wrote: Hmmm, this has me wondering: What phase analysis tools are out there in common use? Soundcraft's small B100 and BVE100 broadcast mixers have an onboard phase meter. Yes, and there are a lot of the outboard meters like the Dorrough and RTW meters that have basic phase metering. I never found these to be all that useful, though. They don't really tell you anything that mono summing doesn't tell you, and they aren't any help for getting a sense of stereo imaging in bad monitoring situations. An X-Y display like the Tektronix audio monitor is very useful for getting a sense of stereo imaging when you can't trust your monitors, and it can be very handy for broadcast and record-cutting work where the sum and difference channels are asymmetric. But you very seldom see them any longer. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." So in effect you're saying that, despite all this talk about group delay and such, there aren't any tools in common use that quantify these effects? Later... Ron Capik -- |
#39
|
|||
|
|||
Ron Capik wrote:
So in effect you're saying that, despite all this talk about group delay and such, there aren't any tools in common use that quantify these effects? Uhh... wait. I was talking about devices that indicate relative phase between channels. Which has nothing to do with group delay (phase distortion), although it can tell you about polarity errors. All of which are three different things. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#40
|
|||
|
|||
One of the best phase-analysis tools is an oscilloscope -- left channel to
vertical, right to horizontal. |
Reply |
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Phase Correction | Pro Audio | |||
mixed crossover phase question | Tech | |||
Richman's ethical lapses | Audio Opinions | |||
Transient response of actively filtered speakers | Tech | |||
Negative/Positive Phase Shift in a Transformer | Pro Audio |