Home |
Search |
Today's Posts |
#1
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
Hi:
Most so-called "FM synths" actually use Phase Modulation Synthesis. So why are they still referred to as FM? Wouldn't it be more appropriate could to call them "PM synths"? Also, isn't the math involved in PM Synthesis significantly different from that in FM Synthesis? Does studying the math of FM synthesis do much good when it is actually a PM synth you're trying to design/build? Thanks |
#2
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
I don't know the details, but FM and PM are essentially the same thing. Take
the derivative of the signal, apply it to a PM transmitter, and you have FM. (Or did I get that backwards? Doesn't matter -- as Tom Lehrer said, "It's the principle that counts.") In fact, AM can be modeled as a form of weak FM or PM modulation. At least one ultra-high-power AM broadcast transmitter has been built using this principle. |
#3
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
William Sommerwerck wrote:
I don't know the details, but FM and PM are essentially the same thing. Take the derivative of the signal, apply it to a PM transmitter, and you have FM. (Or did I get that backwards? Doesn't matter -- as Tom Lehrer said, "It's the principle that counts.") Yes, it's just a matter of one dot on top of a variable. In fact, AM can be modeled as a form of weak FM or PM modulation. At least one ultra-high-power AM broadcast transmitter has been built using this principle. I think you're thinking of PWM here.... the big AM transmitters that are basically Class-D amps. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#4
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
In fact, AM can be modeled as a form of weak FM or PM modulation.
At least one ultra-high-power AM broadcast transmitter has been built using this principle. I think you're thinking of PWM here... the big AM transmitters that are basically Class-D amps. Perhaps, but I read about a PM transmitter that used a phase-shifting circuit (_after_ the final) to convert the signal to AM. This eliminates the need for a huge audio-amplifier modulator. |
#5
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
In article
, GreenXenon wrote: Hi: Most so-called "FM synths" actually use Phase Modulation Synthesis. So why are they still referred to as FM? Wouldn't it be more appropriate could to call them "PM synths"? Also, isn't the math involved in PM Synthesis significantly different from that in FM Synthesis? Does studying the math of FM synthesis do much good when it is actually a PM synth you're trying to design/build? Thanks FM synthesis was patented by John Chowning and Stanford University and exclusively licensed to Yamaha. Phase modulation was unfortunately not covered by the patent and eventually developed by Casio as phase distortion synthesis. Stanford's attorneys should have done a little more research apparently. Both techniques are now in the public domain as I understand it. -Jay |
#6
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
On Aug 21, 12:27*pm, Jay Kadis wrote:
In article , *GreenXenon wrote: Hi: Most so-called "FM synths" actually use Phase Modulation Synthesis. So why are they still referred to as FM? Wouldn't it be more appropriate could to call them "PM synths"? Also, isn't the math involved in PM Synthesis significantly different from that in FM Synthesis? Does studying the math of FM synthesis do much good when it is actually a PM synth you're trying to design/build? Thanks FM synthesis was patented by John Chowning and Stanford University and exclusively licensed to Yamaha. *Phase modulation was unfortunately not covered by the patent and eventually developed by Casio as phase distortion synthesis. *Stanford's attorneys should have done a little more research apparently. *Both techniques are now in the public domain as I understand it. -Jay Holly crap they are in PD - I'm way to old! |
#7
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
Danny T wrote:
Holly crap they are in PD - I'm way to old! No sir, you are properly seasoned... ---Jeff |
#8
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
On Aug 21, 2:00*pm, Arkansan Raider wrote:
Danny T wrote: Holly crap they are in PD - I'm way to old! No sir, you are properly seasoned... ---Jeff Properly.... or perhaps, texmex :-) |
#9
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
Danny T wrote:
On Aug 21, 2:00 pm, Arkansan Raider wrote: Danny T wrote: Holly crap they are in PD - I'm way to old! No sir, you are properly seasoned... ---Jeff Properly.... or perhaps, texmex :-) LOL Well you certainly spiced up *that* joke. Heh. ---Jeff |
#10
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
On Fri, 21 Aug 2009 10:27:16 -0700, Jay Kadis
wrote: FM synthesis was patented by John Chowning and Stanford University and exclusively licensed to Yamaha. Phase modulation was unfortunately not covered by the patent and eventually developed by Casio as phase distortion synthesis. Stanford's attorneys should have done a little more research apparently. Both techniques are now in the public domain as I understand it. As similar as PM and FM may be on paper, the Casio CZ and Yamaha DX gear sounded completely different. I've spent some time developing patches for both. Maybe Yamaha would have been more inclined to sue if Casio was trying to clone the DX. |
#11
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
On Fri, 21 Aug 2009 22:56:44 +0000, David Light wrote:
On Fri, 21 Aug 2009 10:27:16 -0700, Jay Kadis wrote: FM synthesis was patented by John Chowning and Stanford University and exclusively licensed to Yamaha. Phase modulation was unfortunately not covered by the patent and eventually developed by Casio as phase distortion synthesis. Stanford's attorneys should have done a little more research apparently. Both techniques are now in the public domain as I understand it. As similar as PM and FM may be on paper, the Casio CZ and Yamaha DX gear sounded completely different. I've spent some time developing patches for both. Maybe Yamaha would have been more inclined to sue if Casio was trying to clone the DX. One difference I found was that a low frequency or static modulator oscillator causes a pitch change in the carrier with FM, but not with PD. Also with PD there always seems to be more of the oscillator's fundamental pitch present in the sound. The PM (or 'Phase Distortion' as Casio called them) synths sound warmer to me, and are easier to program, but are a bit more limited for extreme sounds. To enable them to get decent 'helicopter crashing into a burning string quartet' noises, Casio added ring mod. My VZ-10M has eight oscillators and four ring mods per voice, and you can stack four voices together, which adds up to a lot of chaos. |
#12
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
GreenXenon wrote:
Hi: Most so-called "FM synths" actually use Phase Modulation Synthesis. So why are they still referred to as FM? Wouldn't it be more appropriate could to call them "PM synths"? Who told you that ? It's FM. geoff |
#13
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
On Aug 21, 1:27*pm, Jay Kadis wrote:
In article , *GreenXenon wrote: Hi: Most so-called "FM synths" actually use Phase Modulation Synthesis. So why are they still referred to as FM? Wouldn't it be more appropriate could to call them "PM synths"? Also, isn't the math involved in PM Synthesis significantly different from that in FM Synthesis? Does studying the math of FM synthesis do much good when it is actually a PM synth you're trying to design/build? Thanks FM synthesis was patented by John Chowning and Stanford University and exclusively licensed to Yamaha. *Phase modulation was unfortunately not covered by the patent and eventually developed by Casio as phase distortion synthesis. *Stanford's attorneys should have done a little more research apparently. *Both techniques are now in the public domain as I understand it. -Jay Does anyone still make an FM synth? I guess I'll always associate FM sound with DX-7's and bad 80's songs, neither of which are pleasant memories for me. -Neb |
#14
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
On Aug 21, 6:56 pm, "geoff" wrote:
GreenXenon wrote: Hi: Most so-called "FM synths" actually use Phase Modulation Synthesis. So why are they still referred to as FM? Wouldn't it be more appropriate could to call them "PM synths"? Who told you that ? It's FM. geoff Quote from http://en.wikipedia.org/wiki/Frequen...tion_synthesis : "It should be noted that the implementation commercialized by Yamaha (US Patent 4018121 Apr 1977) is actually based on phase modulation." Quote from http://www.midibox.org/forum/index.p...,11394.75.html : "The OPL3 (and other "frequency modulation" synths) actually use phase modulation instead of frequency modulation. The reason is that a DC offset (eg non-zero amplitude at 0Hz) will give a frequency shift in FM but only a phase shift in PM. See http://www.nic.funet.fi/pub/sci/audio/misc/pm-intro for more information." |
#15
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
nebulax wrote:
Does anyone still make an FM synth? Native Instruments has a virtual machine which can even use the same programs as the DX7. -- Jon -- - "Coloured and animated, the concerts and spectacles are as many invitations to discover the universes of musicians and artists who tint with happiness our reality." |
#16
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
GreenXenon wrote:
"The OPL3 (and other "frequency modulation" synths) actually use phase modulation instead of frequency modulation. The reason is that a DC offset (eg non-zero amplitude at 0Hz) will give a frequency shift in FM but only a phase shift in PM. See http://www.nic.funet.fi/pub/sci/audio/misc/pm-intro for more information." So a simple LFO onto an operator gives no modulation on my DX7 ? geoff |
#17
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
nebulax wrote:
Does anyone still make an FM synth? I guess I'll always associate FM sound with DX-7's and bad 80's songs, neither of which are pleasant memories for me. I have heard some pleasant DX sounds. But songs (of the 80s or whenever) have little to do with the instruments used. geoff |
#18
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
geoff wrote:
nebulax wrote: Does anyone still make an FM synth? I guess I'll always associate FM sound with DX-7's and bad 80's songs, neither of which are pleasant memories for me. I have heard some pleasant DX sounds. But songs (of the 80s or whenever) have little to do with the instruments used. The songs of the 80s mostly had to do with wearing very loud leisure suits and putting upside-down flower pots on your head. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#19
Posted to rec.audio.pro
|
|||
|
|||
Why is it called FM synthesis?
|
Reply |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Computer speech synthesis | Tech | |||
Analog Synthesis Sucks! | Tech | |||
WTB: Audio Synthesis Passion passive pre | Marketplace | |||
WTB: Audio Synthesis Passion passive pre | Marketplace | |||
A question to Mr. Arny Krueger (synthesis) | Audio Opinions |