[PD] Analog square wave?

Pierre Massat pimassat at gmail.com
Mon Feb 6 20:21:07 CET 2012


Thank you all for your advice. The plain digital square wave doesn't sound
well (I use it as an LFO in a ring modulator. I've just added some partials
to my bandlimited square wave and now it works ok.
I'll try [sqosc~] though.

Cheers,

Pierre.

2012/2/6 Martin Peach <martin.peach at sympatico.ca>

> You can use [mrpeach/sqosc~] bandlimited to a low frequency as an LFO.
> Since [sqosc~] is slew-rate limited according to the bandwidth limit, the
> peaks are absolutely flat and there is no overshoot, and the transitions
> are smooth.
>
> Martin
>
>
> On 2012-02-06 09:43, chris clepper wrote:
>
>> In an analog synth the square wave has some distortion to it: the rise
>> is not instantaneous and there is some overshoot of the peak too.  Over
>> the years this was minimized by using high slew rate amp circuits and
>> the like so an old Moog pulse wave is less ideal in shape than a new one.
>>
>> For a digital square wave you would want to use band limiting to avoid
>> alias artifacts which are quite severe for a square or sawtooth wave.
>> As the frequency goes higher both of those waves will begin to look more
>> like sine waves as the partials are filtered out.  Pretty much every
>> commercial digital synth and plugin uses anti-aliased waveforms.
>>
>> On Mon, Feb 6, 2012 at 8:31 AM, Pierre Massat <pimassat at gmail.com
>> <mailto:pimassat at gmail.com>> wrote:
>>
>>    Dear List,
>>
>>    I need a square wave to use as an LFO in a ring mod patch. Though i
>>    could simply use [expr~ $v1>0.5], I m wondering if I could get a
>>    smoother square wave. I tried to use a bandlimited square wave, but
>>    I don't have enough harmonics and the top of the wave isn't flat
>>    enough. Incidentally, what do analog square waves from old synths
>>    look like? Anyway, I think i want a square wave with no jumps
>>    between 0 and 1.
>>
>>    Cheers!
>>
>>    Pierre.
>>
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