[sdiy] PM vs FM was: Re: Buchla 295 10-band comb filter topology

[Tom Wiltshire]

> On 27 Nov 2022, at 21:02, Matthew Skala via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> On Sun, 27 Nov 2022, René Schmitz wrote:
> 
>> In a nutshell the difference between PM and FM is what happens when the
>> modulating operator has a DC offset.
>> 
>> With plain FM you get a net de-tuning (and your note is off), with PM you only
>> get an inaudible phase difference.
>> 
>> This is what makes PM the mode that is musically more useful.
> 
> Ah, I see this after writing my response to David's message.  You're
> talking about the digital realm, which is a little different from analog;
> there's not going to be a DC offset through a coupling capacitor, of
> course, but it's at least conceivable an offset could exist in a digital
> signal.  I'm still skeptical of it coming up *frequently* and making a
> *categorical* difference.

Doesn't have to be "categorical". It just has to be enough to add up over time and make your notes sound badly out of tune. That doesn't take much. Especially in a cascade of six operators as a worst case.