[sdiy] [synth-diy] numerically controlled superoscillato without hard sync

[Dan Snazelle]

wow

this module uses a raspberry pi AND an arduino to run CSOUND! in the modular world


nice!



Sent from my iPhone

> On Feb 10, 2014, at 11:04 PM, "Paul Burns (Fitvideo)" <paul at fitvideo.co.uk> wrote:
> 
> Slightly OT but in regard to Csound, there is a guy on Muffs who has created
> 3 x 2-op fm oscillators that respond to pitch and are tuneable against each
> other, using this module.
> 
> http://www.qubitelectronix.com/#!nebulae/c23nm
> 
> 
> http://www.muffwiggler.com/forum/viewtopic.php?t=104514&start=all&postdays=0
> &postorder=desc
> 
> cheers and regards
> 
> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl
> [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Declare Update
> Sent: 09 February 2014 20:13
> To: Jim Credland
> Cc: synth-diy
> Subject: Re: [sdiy] [synth-diy] numerically controlled superoscillator
> without hard sync
> 
> I have recently been pondering this same idea! I was thinking you'd have a
> pin change trigger an ISR, which just increments the index to a wave table.
> So you're driving vco would have to be the size of your array * desired
> frequency. Clocking the actual micro is an option i guess, but as Tom points
> out, that's pretty fast!
> 
> You mentioned doing a whole VA this way, would that be with separate
> processors for each unit? How would you go about this?
> 
> 
> Sent from my iPhone
> 
>> On Feb 9, 2014, at 12:38 PM, Jim Credland <jim at cernproductions.com> wrote:
>> 
>> I spent some time creating tones in csound with additional aliased
> overtones (i just added a sine wave and calculated the frequency) - it
> sounded great - though that approach wouldn't have worked with complex
> waveforms very easily.
>> 
>> Also, the Tip Top Audio Z-DSP lets you do this type of thing.  You can
> clock the DSP chip with another oscillator.   I've not tried driving it with
> a melody yet though - that might be pretty interesting.
>> 
>> I'm going to try it right now!
>> 
>>> On 9 Feb 2014, at 17:08, cheater00 . <cheater00 at gmail.com> wrote:
>>> 
>>> Hi,
>>> 
>>> thinking about this recently, one could use a high-frequency 
>>> oscillator, and use it as the clock for a microcontroller which 
>>> assuredly outputs a single sample every n clocks. This way you can 
>>> perform VA style synthesis where the time base is derived from an 
>>> analog oscillator that can perform FM and other neat analog tricks. 
>>> On the other hand the uC only has to synthesize at a single 
>>> frequency. So say it's always synthesizing at A440, and you change 
>>> the pitch by changing how fast it executes its algorithm, i.e. by 
>>> changing the clock, i.e. by changing the sampling frequency. This 
>>> way, externally (i.e. at the output of the DAC) the aliases are 
>>> always precisely at the same position in relation to the base 
>>> frequency of the note being played. The aliases become part of the
> timbre, enriching it.
>> 
>> 
>>> This is
>>> in contrast to aliasing in a system where the sampling frequency is 
>>> fixed, and the pitch of the note being synthesized is changed in the 
>>> usual way. In this case, which doesn't happen here, the aliases are 
>>> at a different position for every pitch, and therefore the oscillator 
>>> not only plays your desired melody, but also a quieter, undesired 
>>> melody which is completely out of tune and works against your music.
>>> 
>>> The variable sample rate oscillator could also contain things like 
>>> filters and other stuff. A whole VA could be implemented, and 
>>> aliasing is not an issue at all.
>>> 
>>> The only thing you need to ensure is that your reconstruction filter 
>>> works well with a variable sample rate.
>>> 
>>> Cheers,
>>> D.
>>> _______________________________________________
>>> Synth-diy mailing list
>>> Synth-diy at dropmix.xs4all.nl
>>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>> 
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