[PD] Synths! (Please Read)

[Martin Peach]

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 at 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
>>
>>
>>_______________________________________________
>>PD-list at iem.at mailing list
>>UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
>>
>>    
>>
>
>
>--
>"It is not when truth is dirty, but when it is shallow, that the lover
>of knowledge is reluctant to step into its waters."
>-Friedrich Nietzsche, "Thus Spoke Zarathustra"
>
>_______________________________________________
>PD-list at iem.at mailing list
>UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
>
>  
>