Re: [LAU] Octaver or fuzztone effect

Hi,

the software equivalent to a diode rectifier would be [abs~] in pd for
example. But to make it sound as sweet as in the analogue world, one has
to include some unlinearities in the signal path as well.

cheers, Peter

Folderol wrote:
> On Sat, 26 May 2007 11:09:49 -0700
> Ken Restivo <ken@email-addr-hidden> wrote:
>
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>> On Sat, May 26, 2007 at 04:38:46PM +0200, Georg Holzmann wrote:
>>> Hallo!
>>>
>>>> http://www.geocities.com/CollegePark/Library/1355/tonemachine.gif
>>>> http://www.geofex.com/FX_images/foxxfuzz.gif
>>> Okay, I did not mean the circuit, but a schema of the mathematic behind
>>> it ... ;)
>>> Then it should be easy to build in software ...
>>>
>> Maybe model the circuit in something like SPICE, and have a look at what the modelled circuit does to a sine-wave input, or, and impulse?
>>
>> http://www.linuxjournal.com/article/2169
>>
>> Hmm. An interesting project might be hacking SPICE into being a kind of a deconvolution engine, to build a WAV impulse response file of a circuit. Then you could use that IR to "play" through the circuit using JACE or similar.
>>
>> The maths involved in such a thing would be way beyond my meager skills, however.
>>
>> - -ken
>
> The preamp stage gives some filtering that seems to lift at around 3kHz
> (fairly typical 'brightness').
>
> The funny bit is a variation on a full-wave rectifier which has the
> effect of crude frequency doubling. Instead of a switch it is better to
> make the 'bottom' half variable so you can control the amplitude of the
> doubled effect. Don't know quite how you'd do this is software, you
> need to sort of 'fold' the signal so the negative bits go positive
> instead.
>
> That is followed by a single amplifier giving the drive to an
> ordinary 2 diode limiter (fuzz). This kind of limiter doesn't give
> a hard cutoff, but a slightly rounded waveform - sounds smoother. The
> 'sustain' control is simply drive level. More drive = more distortion
> and longer before it comes out of limiting.
>
> Followed by a slightly unusual tone control - quite interesting - and
> a final buffer amp.
>
>
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Received on Sun May 27 08:15:01 2007