On Sun, Jun 25, 2006 at 04:21:20 -0400, Dave Robillard wrote: > > It's all about modulation, if I connect a [-1.0, 1.0] sine LFO to a cutoff > > modulation input then I want it to modulate up and down by N octaves, not > > N Hz, frequency-linearly symmetric modulations sound wrong. My favourite > > (digital) modular filters have a centre frequnecy (shown in Hz, expoentialy > > scaled control) and a modulation input that modulates in octaves. > > > > You want the modulation to be musically relevent, and the most musically > > useful unit for pitch is octaves :) Humans aren't SI sadly. > > > > I agree that describing it as volts is a bit odd, but it instantly makes > > people like me feel at home. There's not reason why a digital modular neds > > units for its modulation sources. It's just real numbers. > > This is true, but there are other cases when you want a real, meaningful > frequency to do something with (using the same plugin). Eg lowpass all > frequencies above 800Hz. Someone working on a DAW definitely doesn't > want to deal with this meaningless V/Oct unit.
That's why I said you have a centre frequency control, that's set in Hz. > Of course, in a modular you can convert Hz frequencies to VOct > frequencies, and in a DAW you can convert VOct frequencies to Hz, but in > both cases it's a user nuisance, so it needs to be automatic. My gripe > isn't with the unit itself, so much as in the current situation with > LADSPA it's a really, really huge PITA to have a mess of twisty little > units, all alike. Yes, but neccesary, unless your hosts all understand the semantics of pitch/frequency and are willing to do lots of pow() based conversions. > Of course LV2 will let us solve this, and the frequency unit can in both > cases be kept entirely transparent by the host (if you want), making the > actual unit used by a plugin just an optimization as it should be > (skipping the conversion step). s/will/could/, I'm not yet convinced that it's appropriate. My preference would still be for a Hz centre control and a (high rate) modulation input. If there's a sane representation in RDF for a single port to do both things well, then I'm all for it, but I'm scpetical. - Steve
