interesting application of dsp to music/audio

On Mon, 15 Jun 2015 13:36:21 -0400, Randy Yates
<yates@digitalsignallabs.com> wrote:

>N0Spam@daqarta.com (Bob Masta) writes:
>
>> On Sun, 14 Jun 2015 12:23:02 +0000 (UTC),
>> spope33@speedymail.org (Steve Pope) wrote:
>>
>>>Bob Masta <NoSpam@daqarta.com> wrote:
>>>
>>>>On Sat, 13 Jun 2015 14:10:34 -0400, Randy Yates
>>>
>>>>>I wouldn't call it a vocoder. A vocoder uses subtractive synthesis,
>>>>>while this technique uses additive synthesis (or you could call it a
>>>>>type of additive synthesis). Also, a vocoder has two input channels,
>>>>>while this only has one.
>>>
>>>>Apparently there must be vocoders out there that I haven't
>>>>heard about, or you are using a different definition of
>>>>"subtractive synthesis" than conventional music synth usage.
>>>
>>>>The classical vocoder is a bank of filters applied to the
>>>>(single) input channel, each filter followed by some sort of
>>>>detector, which then controls the amplitude of an oscillator
>>>>(typically at the same frequency as the filter channel
>>>>center).  That's pretty much exactly what the piano gadget
>>>>is doing.
>>>
>>>My belief is "vocoder" originally meant "voice encoder / decoder"
>>>(or something close to that) and there were at least two
>>>very common techniques, the phase vocoder being one, the others
>>>mostly based on linear prediction (which could be said to be 
>>>"subtractive" but has nothing to do with "subtractive" synthesis 
>>>in electronic music.
>>
>> Apologies to Randy... I should have checked Wikipedia
>> instead of relying on my ever-greying grey cells.  
>
>Hi Bob,
>
>No problem. Been there, done that!
>
>> I was neglecting that the channel envelope followers in classical
>> vocoders controlled *filters*, not *oscillator* amplitude. So of
>> course the filter signal input is Randy's second input channel, and
>> the filtering would be the subtractive synthesis he mentioned.
>
>Yes, exactly! Now we're communicating.
>
>> [...]
>
>>>Anything similar to these voice coders also got called (by somebody..
>>>does anyone remember who?) "vocoders" in electronic music.
>>>But these could be broadly different from the original concepts.
>>>
>>>Steve
>>
>> Googling up on it now, it seems Moog and Carlos were using
>> the full vocoder concept Back In The Day.  But I seem to
>> recall an "experimental" guy with a German or Eastern
>> European name.  Hafta dig through my dead tree collection...
>
>When you say "Carlos" did you mean Wendy Carlos (the switched-on-Bach
>dude)?

The very same.  In fact, I have that album from the actual
"dude" (Walter Carlos) days.  Maybe it is a "collectible"
now?

>I was also trying to think of who Steve was referring to but came up
>blank.
>-- 
>Randy Yates
>Digital Signal Labs
>http://www.digitalsignallabs.com

----

Bob Masta
 
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