Re: Simulating Vibrato With Sine Wave
Re: Simulating Vibrato With Sine Wave
- Subject: Re: Simulating Vibrato With Sine Wave
- From: Richard Dobson <email@hidden>
- Date: Mon, 01 Feb 2010 15:24:22 +0000
For vibrato (pitch variation) a plain sine-modulated (and interpolating)
variable delay line will do it very nicely. For tremolo (amplitude
variation) you simply have to set your median level and mod level, and
multiply signal with your slow sine. Median level +- sine amplitude must
be all positive, and < 1.0. E.g. set sine to range between 0.25 and
0.75, to get a 6dB variation : vibsig = 0.25 + (0.5 * sin(w)); out = in
* vibsig. To sound like real human vibrato, the frequency of the sine
and/or amplitude should be a little randomised; which is where things
get "interesting".
This is unrelated to spatialisation, so why one would bother with OpenAL
for this sort of thing is a separate question, to which I have no answer.
Richard Dobson
On 01/02/2010 01:27, Hank Heijink (Mailinglists) wrote:
I'm not very familiar with OpenAL, but vibrato is more complicated
than putting a sin on a signal, especially if you're looking for
something that's musically convincing. Tremolo is a lot easier and
may in fact be what you're after. Have you looked at Apple's
TremoloUnit example?
http://developer.apple.com/mac/library/samplecode/TremoloUnit/
It's not OpenAL, but you may find it helpful.
Good luck, Hank
On Jan 31, 2010, at 7:51 PM, Chunk 1978 wrote:
please excuse my lack of math skills (i'm more of a creative
person than a gifted programmer), but i'd like to know if there is
a general algorithm for OpenAL that uses sin() on a sound object's
pitch property that is popular for simulating the vibrato effect?
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