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.
Don't know about real analog squares, probably way more complex, but attached is my simplistic approach: a soft-clipped triangle wave gr, Tim
2012/2/6 Pierre Massat pimassat@gmail.com
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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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@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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- chris clepper cgclepper@gmail.com [2012-02-06 15:49]:
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.
out of interest Chris, do they use wavetables (possible of different lengths for different octaves) or internal oversampling a la Millers example in the doc patches?
best, P
On Mon, Feb 6, 2012 at 8:31 AM, Pierre Massat pimassat@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.
Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
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On Mon, Feb 6, 2012 at 10:01 AM, Peter Plessas plessas@mur.at wrote:
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.
out of interest Chris, do they use wavetables (possible of different lengths for different octaves) or internal oversampling a la Millers example in the doc patches?
I can't really speak for any manufacturers but it probably varies based on the hardware being used.
something like this?
http://vimeo.com/groups/puredata/videos/36172013
Am 06.02.2012 um 18:03 schrieb chris clepper:
On Mon, Feb 6, 2012 at 10:01 AM, Peter Plessas plessas@mur.at wrote:
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.
out of interest Chris, do they use wavetables (possible of different lengths for different octaves) or internal oversampling a la Millers example in the doc patches?
I can't really speak for any manufacturers but it probably varies based on the hardware being used. _______________________________________________ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
On Mon, Feb 06, 2012 at 09:43:29AM -0500, 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.
However when using this as a LOW frequency oscillator, I would simply ignore the literature on bandlimiting and go with a pure digital aliased wave full force! :)
Ciao
Frank Barknecht Do You RjDj.me? _ ______footils.org__
On Mon, 2012-02-06 at 17:56 +0100, Frank Barknecht wrote:
However when using this as a LOW frequency oscillator, I would simply ignore the literature on bandlimiting and go with a pure digital aliased wave full force! :)
Good practical advice... if you really start thinking about what is going to happen when you take a digital square wave and use it as a modulator on some other signal, probably by something evil and nonlinear like multiplying the signals together, you can give yourself a headache quite quickly!
Just remember, one person's "aliasing artifacts all over the spectrum" is another person's "gritty, trashy, beautiful dirt".
Thanks, Bill Gribble
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@gmail.com mailto:pimassat@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. _______________________________________________ Pd-list@iem.at <mailto:Pd-list@iem.at> mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
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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@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@gmail.com mailto:pimassat@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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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.
Do you think a wave file of an analog square could be helpful?
-
Bill Gribble -
chris clepper -
Frank Barknecht -
Martin Peach -
Max -
Peter Plessas -
Pierre Massat -
tim vets -
Vincent Kaschner