[sdiy] Why Bands for String Filters and Narrow and Numerous

[Mike HEQX]

Really great explanation.

Thanks Brian


On 7/1/2017 11:27 PM, rsdio at audiobanshee.com wrote:
> On Jul 1, 2017, at 7:15 PM, Mike HEQX <mike at heqx.com> wrote:
>> Is it true that you could invert the whole thing into numerous oscillators instead of numerous filters to create the harmonics? Or would that sound like crap?
> It would certainly depend upon how dynamic the oscillators are.
>
> With a filter bank, you can have fixed frequencies, and it will still be melodic because the pitch of the incoming string (sawtooth) waveforms is dynamic. The filter bank simply makes the simple oscillator sound more rich. I'm quite certain that you can play a full 10-note chord through a single filter bank and it would still sound quite full without compromising the chord.
>
> If you tried to do this with numerous oscillators, the first challenge is that those oscillators would have to track all of the incoming frequencies. If you play a 10-note chord, will there be enough oscillators to recreate every note? Other challenges would be whether there are enough oscillators to compete with other string synthesis techniques.
>
> At first, I thought you might be suggesting that a series of sine waves could produce a sawtooth wave when mixed, but that would really be the hard way to do it and would probably come up lacking. Of course, you can have a series of sawtooth waves, so long as there are enough to replicate a symphony of strings.
>
>
> This reminds me of the string synth circuit that has three Top Octave Generators. They're each modulated slightly different than the others, with varying phases of the same modulator (or perhaps even different modulators). This way, playing a note or a chord produces a chorus of three pitches that sound fuller than a solo synth.
>
> One thing I was thinking about is that each violin can only play one to four notes, but a string synthesizer can play many more notes. However, a symphony of violinists can play way more strings together than just one to four, although I don't know how often they play in unison versus coordinating to play expanded chords across multiple instruments. I'm only thinking about this in terms of recreating string sounds that can operate in play of an orchestra and not come up too lacking.
>
> Has anyone done a comparison of various string synth designs? Pitting plain sawtooth against the same with chorus, or with a filter bank, or with this triple TOG technique… it would be interesting to hear which ones sound the most pleasing or richest.
>
> Brian
>
>
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