[sdiy] vocoder : synthesizer part

[James Patchell]

Looks like I answerd the wrong email.....

At 09:51 AM 3/27/2004 -0800, James Patchell wrote:
>http://www.grizzly.com/catalog/2004/483.cfm?
>
>At 06:32 PM 3/27/2004 +0100, jhaible wrote:
>>Some Vocoders use a pwm'd switch as a VCA - you can only do this before
>>the filters.
>>Also, BPFs after the VCAs will ring / decay smoothly even if the VCA
>>would shut down very fast.
>>
>>JH.
>>
>>-----Ursprüngliche Nachricht-----
>>Von: Magnus Danielson <cfmd at bredband.net>
>>An: <jbv.silences at club-internet.fr>
>>Cc: <synth-diy at dropmix.xs4all.nl>
>>Gesendet: Samstag, 27. März 2004 15:43
>>Betreff: Re: [sdiy] vocoder : synthesizer part
>>
>>
>> > From: jbv <jbv.silences at club-internet.fr>
>> > Subject: [sdiy] vocoder : synthesizer part
>> > Date: Sat, 27 Mar 2004 13:08:46 +0100
>> > Message-ID: <40656ECB.63102EBD at Club-Internet.fr>
>> >
>> > > Hi,
>> > >
>> > > I just noticed that in the synthesizer part of a vocoder
>> > > the design can vary : some (like Elektor vocoder AFAIR)
>> > > place the VCA after the BPF, while others (like Roland
>> > > SVC-350 or the Moog vocoder) place the VCA before the
>> > > BPF.
>> > > Is there any good reason to choose one design or the other ?
>> >
>> > Depends on your VCA and your filter. If you have a noisy VCA, you place
>>the
>> > filter after it to filter out the noise, but if you have a noisy filter,
>>the
>> > VCA will only open it up when there is signal anyway.
>> >
>> > Then there is those where the "VCA" has alot of extra energy, so the
>>filter
>> > goes afterwards anyway.
>> >
>> > From a theoretical point of view (noiseless and distorsionless ideal)
>>putting
>> > them one way or another is equalent, but it is the flaws and how you best
>>hide
>> > them which really decides which way to go. Recall that you have this flaw
>>times
>> > the number of channels your vocoder has, so they add up quite quickly.
>> >
>> > Cheers,
>> > Magnus
>> >
>
>         -Jim
>***************************************************************
>         Be sure to attend the PSW Synth DIY meet
>Come for the fun....
>Come to meet fellow DIYers
>
>Details at:
>http://www.oldcrows.net/~patchell/SynthDIY2004.html
>***************************************************************
>http://www.oldcrows.net/~patchell
>
>***************************************************************
>
>

         -Jim
***************************************************************
         Be sure to attend the PSW Synth DIY meet
Come for the fun....
Come to meet fellow DIYers

Details at:
http://www.oldcrows.net/~patchell/SynthDIY2004.html
***************************************************************
http://www.oldcrows.net/~patchell

***************************************************************