Super filter No filter

[Bissell, Harry]

If you are going to process only a "digital sawtooth", you just need
sinewaves to satisfy the the 'recipe' for a sawtooth, i.e. F(a) + 2F (1/2a)
+3F (1/3a)... until you leave the audio spectrum. No "filters" at all are
needed. These sinewaves would all be in phase, and your "filter" algorithm
would reduce the amplitudes progressively from the maximum.

But (caveat) you can't simulate the non-harmonic response of a resonant
filter.
A low-pass is easy, but those "in-between" points where the harmonic is
almost at a peak won't sound the same.  

The "ladder" is out of patent by now, isn't it.  Analog Rules!!!    Harry
Bissell

> -----Original Message-----
> From:	Guido Goebertus [SMTP:guidogoe at xs4all.nl]
> Sent:	Wednesday, March 03, 1999 3:17 PM
> To:	synth-diy at mailhost.bpa.nl
> Subject:	Super filter No filter
> 
> Gene wrote:
> 
> >List,
> >
> > A recent thread about waveform synthesis reminded me of an  idea I had
> >about 25 years ago when I was into synths. I wanted to build a single
> >voice channel (ala Moog).
> 
> You could still use the vocoder idea. I thought this over for as many
> years. (Well, almost:-).
> You'll need to program a DSP with a lot of bandpass filters if you want to
> do this digital. You'll also need a (digital) sawtooth to process.
> This, to my knowlegde hasn't been done before to process a single voice.
> But it would certainly sound very different compared to additional
> synthesis, because it  is still subtractive, like analog synths.
> I am working on this right now, but analog for the moment.
> Maybe later I decide to programm my DSP-board.
> 
> Regards, Guido