Hi list, continuing my experiments with vibrato and glissandos, I ended up in this: I´d like to have a vibrato around a certain frequency, in which I can decide to go upwards of a certain amount (ie one octave) but downwards a different one (ie. one 5th), and the possibility to control those parameters. In other words, I´d like to have a modulating wave that has a certain amplitude when goes up, and a different one when goes down. I do not want to use a sine wave with an offset, because I would lose the regularity of the 0 amplitude point. A friend suggested me to use two sine waves with same frequency but different amps and "half rectify" them, in the first excluding the negative values and in the second the positives, in order to create this pseudo-sine wave. See half-wave rectification here: http://en.wikipedia.org/wiki/Rectifier I made a simulation of the kind of wave I´m thinking, see attached jpg file. But, once again, I don´t know how to do that in pd, and I don´t know if there are better ways to do that. Hope my explanation is enough clear! thanks
libero
Libero Mureddu Vanha Viertotie, 21 as 417 00350 Helsinki Finland http://webusers.siba.fi/~limuredd/ http://www.myspace.com/liberomureddu
Libero Mureddu wrote:
In other words, IŽd like to have a modulating wave that has a certain amplitude when goes up, and a different one when goes down. I do not want to use a sine wave with an offset, because I would lose the regularity of the 0 amplitude point. A friend suggested me to use two sine waves with same frequency
They also need the same phase - simplest way is to use one [osc~] and two [*~].
but different amps and "half rectify" them, in the first excluding the negative values and in the second the positives, in order to create this pseudo-sine wave.
[max~ 0] and [min~ 0] will help here.
Also [+~] to combine them after half-rectification.
Hope this helps.
Claude
On Tue, 6 Nov 2007, Claude Heiland-Allen wrote:
but different amps and "half rectify" them, in the first excluding the negative values and in the second the positives, in order to create this pseudo-sine wave.
[max~ 0] and [min~ 0] will help here. Also [+~] to combine them after half-rectification. Hope this helps.
The curve won't have a continuous derivative, which may sound weird if the curve is played slow enough. If ever your solution is not sufficient, it might be better to try to come up with the integral of some continuous function, but it may be a bit hard to make it align with the desired frequencies.
for wide vibratos, it's also important to ask yourself which scale you want to work in: linear vs logarithmic sound different for any sufficiently wide vibrato.
_ _ __ ___ _____ ________ _____________ _____________________ ... | Mathieu Bouchard - tél:+1.514.383.3801, Montréal QC Canada
On Nov 7, 2007 12:19 AM, Mathieu Bouchard matju@artengine.ca wrote:
On Tue, 6 Nov 2007, Claude Heiland-Allen wrote:
but different amps and "half rectify" them, in the first excluding the negative values and in the second the positives, in order to create
this
pseudo-sine wave.
[max~ 0] and [min~ 0] will help here. Also [+~] to combine them after half-rectification. Hope this helps.
The curve won't have a continuous derivative, which may sound weird if the curve is played slow enough. If ever your solution is not sufficient, it might be better to try to come up with the integral of some continuous function, but it may be a bit hard to make it align with the desired frequencies.
Actually, and luckily, it doesn´t sound bad, even when it´s very slow. Anyway, thinking about linear vs. logarithmic (and thinking to my less than good knowledge of functions :-), I ended up with a patch (attached) that uses curve~. Do you think it is a good strategy or not? best regards, libero
for wide vibratos, it's also important to ask yourself which scale you want to work in: linear vs logarithmic sound different for any sufficiently wide vibrato.
_ _ __ ___ _____ ________ _____________ _____________________ ... | Mathieu Bouchard - tél:+1.514.383.3801, Montréal QC Canada
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Claude Heiland-Allen -
Libero Mureddu -
Mathieu Bouchard