[sdiy] Buchla 291 simulation 2

[Dave Krooshof]

>>  I found that the level of the resonant peak varies a lot with
>>  the center frequency. There is also a trimmer to adjust
>>  _how_ it varies, but it's not possible to get a even response.
>>  In the low range, peaks are always higher. It can be adjusted
>>  to fall monotonously towards high frequencies, or to create a "dip"
>>  in the mid frequency range.
>>
>>  Can anybody confirm this?
>>  Was this intentional? (Like, creating less emphasis in a region
>>  where harmonics of the source material might have higher
>>  levels anyway?)

I can confirm this behaviour. A Buchla (and some clones)
and the VCS3 were the first analogue synths I learned to play,
and their filters were allways fat in the bass, voicy in the mids.
So that fits your description.

Later on I got allways disappointed with the low resonances
in moog ladders an the like.
And filters with a fixed bandwith in Hz have less resonance
in the lows, as octaves have fewer Hzs there. So I guess
it's a special quality if the buchla BPF to resonate at the lows.



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groets,

_          >^v<  , bassist      _