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<DIV dir=ltr align=left><SPAN class=994582419-13082024><FONT
face=Calibri>Digital. Ugh. I only build analog synthesizers because
it's fun. Coding isn't fun (for me). I know that computer chips can
do anything, and that's why they hold absolutely zero charm for
me.</FONT></SPAN></DIV><BR>
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<FONT size=2 face=Tahoma><B>From:</B> Synth-diy
[mailto:synth-diy-bounces@synth-diy.org] <B>On Behalf Of </B>Mike
Bryant<BR><B>Sent:</B> Tuesday, August 13, 2024 2:38 AM<BR><B>To:</B> Mattias
Rickardsson; Gordonjcp<BR><B>Cc:</B> synth-diy@synth-diy.org<BR><B>Subject:</B>
Re: [sdiy] Best AVAILABLE OTA for building new designs?<BR></FONT><BR></DIV>
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class=elementToProof>The overload problem is one reason to go software.
Lots of algorithms available for setting the starting phases of each tone so
that you are unlikely to overload the output. Though avoid Schroeder-phase
harmonic tone complexes which have an absolutely level envelope as the sound
suddenly changes to a rising chirp.</DIV>
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<DIV dir=ltr id=divRplyFwdMsg><FONT style="FONT-SIZE: 11pt"
face="Calibri, sans-serif"><B>From:</B> Synth-diy
<synth-diy-bounces@synth-diy.org> on behalf of Mattias Rickardsson
<mr@analogue.org><BR><B>Sent:</B> 13 August 2024 10:06<BR><B>To:</B>
Gordonjcp <gordonjcp@gjcp.net><BR><B>Cc:</B> synth-diy@synth-diy.org
<synth-diy@synth-diy.org><BR><B>Subject:</B> Re: [sdiy] Best AVAILABLE OTA
for building new designs?</FONT>
<DIV> </DIV></DIV>
<DIV>
<DIV dir=ltr>Sounds like we are starting to overdesign things a bit here... :-D
<DIV>Btw the "counting notes and keeping total volume constant" idea reminds me
of one of the Unison modes in Roland Jupiter-4, where you depending on the
number of depressed keys get 4-voice unison, 2x 2-voice unison, 3-voice poly or
4-voice poly. The level loss in this mode is remarkable and not very nice,
especially when playing a 3-note chord and getting only 3 voices playing
compared to playing 1 note and getting 4 voces playing.</DIV>
<DIV><BR></DIV>
<DIV>Anyway, I don't think the all-polyphonic voice summing issue should be
too over-thought, but just try to combine </DIV>
<DIV>- a summing where everything fits without clipping</DIV>
<DIV>- a level control that can gain even more so that clipping could occur but
a melody player would have enough output level.</DIV>
<DIV><BR></DIV>
<DIV>One of the trickiest bits is that resonant filters make peak levels vary a
LOT more than you first might think, so you'll have to count with a peak voice
level that is much higher than many typical sounds. </DIV>
<DIV><BR></DIV>
<DIV>Hopefully this is less of a problem in a true PS3100 voice where resonances
are very moderate. In the gainstaging of polysynth designs in general,
there is a huge advantage if you manage to keep filter resonances limited -
everything level related gets easier, but on the other hand it's hard to make a
firm resonance limiter without adding unwanted distortion or side effects to the
filter sound.</DIV>
<DIV><BR></DIV>
<DIV>/mr</DIV></DIV><BR>
<DIV class=x_gmail_quote>
<DIV dir=ltr class=x_gmail_attr>On Tue, 13 Aug 2024 at 08:49, Gordonjcp <<A
href="mailto:gordonjcp@gjcp.net">gordonjcp@gjcp.net</A>> wrote:<BR></DIV>
<BLOCKQUOTE
style="BORDER-LEFT: rgb(204,204,204) 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex"
class=x_gmail_quote>On Tue, Aug 13, 2024 at 07:54:24AM +1000, Adam (synthDIY)
wrote:<BR>> <BR>> <BR>> > On 12 Aug 2024, at 11:38 PM, Mike Bryant
<<A href="mailto:mbryant@futurehorizons.com"
target=_blank>mbryant@futurehorizons.com</A>> wrote:<BR>> > <BR>>
> I think you need to watch some videos of the late Keith Emerson.
He'd happily have twenty or more keys pressed on a Hammond, some of course
held down with knives :-)<BR>> <BR>> David, you might be able to use
this as a "feature"... have a front panel control labelled "Knife
Factor" that switches in a compressor with auto-make-up gain... <BR><BR>Given
that compressors work by controlling their gain based on output level - a
negative feedback loop - I have this feeling that you could probably sum all
the VCA CVs to give a "total output demand" voltage, which could be fed back
to the DAC Vref (taking us back around to the multiplying DAC question) to
depress the output voltage and keep the total level approximately
constant.<BR><BR>"Approximately" because you'd want it to have a bit of
dynamics, you wouldn't want one note to be as loud as ten, but maybe five
should be as loud as ten.<BR><BR>--
<BR>Gordonjcp<BR><BR>________________________________________________________<BR>This
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