Chuckk Hubbard wrote:
My school has one of the first Moogs, which I managed to get my hands on, and a smaller Moog and an Arp 2600. Great fun (an amazing opportunity really), and unlimited microtonality, but not always precise. I don't know much about maintenance, it could just be that they're old, but it doesn't take long for the oscillators to start to wander. Also, not only restricted to octave equivalence, but to 12 notes. It's easy to lose a few hours to their seductive ways, though.
Later synths like the Oberheim Xpander have a microcontroller to handle the patching and MIDI interface but also to tune the voltages. Since the controller frequency is very accurate, it can count frequency and apply voltage offsets to keep it in tune. (It only does this when you ask it to tune though). I was thinking you could use pd to count frequency and a DAC to generate voltages, that way you can have whatever tuning you like, DACs with more bits and better linearity are preferred. I built a circuit using a PIC16F628 and a DAC716 to control analog synths via MIDI. I use pd as a sequencer.
Martin
On 4/3/06, Martin Peach martinrp@vax2.concordia.ca wrote:
Christian Klippel wrote:
hi,
Am Samstag, 1. April 2006 00:31 schrieb Martin Peach:
Chuckk Hubbard wrote:
In my experience, external synths, hardware or software, are completely useless for any sort of polyphonic alternate tuning use, since they don't use Hz.
Older hardware works by Volts per Octave (e.g. Arp, Moog) or Volts per Hertz (e.g. Korg).
ouch .... i would recommend to use such a synth for lfo applications only ... imagine you want a 2 khz sound ... meaning 2 kilovolts ... ;-)
Yeah right...upside down as usual (-; I was trying to say that if you put in 1 Volt you could get (depending on your initial offset) 440Hz and then at 2 volts you get either 880Hz (an octave) on one type of analog synth or 540 Hz (440 + 100 at 100Hz/Volt) on another. That is to say, frequency in an analog synth is determined by offset+(Octave/Volt) or offset + konstant*(Hertz/Volt). Anyway, there is no absolute frequency in an analog synth the way there is in a digital one, and the ratio is usually adjustable too so alternate tunings are much easier to implement.
Martin
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