Wave file as frequency envelope? (Expression Evaluator)

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jpnullnvoid
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Joined: Tue Apr 21, 2009 1:31 pm
Location: Philadelphia, PA USA

Wave file as frequency envelope? (Expression Evaluator)

Post by jpnullnvoid »

Hello all,

It's been a while since I've used the expression evaluator(EE) and there is something I'm trying to achieve with it. Let's say I first create a wave file and use the EE to give it a value of 1, then I use the Shape Volume effect to essentially create an envelope with that file. Is it possible to use that wave file to control the frequency of a tone in the EE? I've been trying, but it's not working - I'm getting strange artifacts. I must be missing something obvious.

Here is an example expression, where "wave2(n)" is the envelope:
sin(2*pi*(f*wave2(n))*t)

Any help is greatly appreciated.

Thanks!

John
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Re: Wave file as frequency envelope? (Expression Evaluator)

Post by GoldWave Inc. »

You'll need to figure out the integral of the wave.
jpnullnvoid
Posts: 39
Joined: Tue Apr 21, 2009 1:31 pm
Location: Philadelphia, PA USA

Re: Wave file as frequency envelope? (Expression Evaluator)

Post by jpnullnvoid »

Ah, that makes sense. Guess I need to brush up on my math. LOL!

Thank you so much!

John
jpnullnvoid
Posts: 39
Joined: Tue Apr 21, 2009 1:31 pm
Location: Philadelphia, PA USA

Re: Wave file as frequency envelope? (Expression Evaluator)

Post by jpnullnvoid »

OK, I've tried brushing up on my math and cannot figure this out. Does anyone understand how one wave file can be used to alter the frequency of a sine wave in the expression evaluator...in layman's terms?

Is that sort of thing not worth the effort?

Any advice is appreciated. Thank you!

John
GoldWave Inc.
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Re: Wave file as frequency envelope? (Expression Evaluator)

Post by GoldWave Inc. »

Not sure if this would work, but maybe you could perform a couple of expressions. In the first expression, you'd calculate the sum of the points in the graph using "wave(n)+wave(n-1)" (essentially the area under the graph, which would be the integral). Then you can use that wave (scaled as necessary) as the modulation function.
jpnullnvoid
Posts: 39
Joined: Tue Apr 21, 2009 1:31 pm
Location: Philadelphia, PA USA

Re: Wave file as frequency envelope? (Expression Evaluator)

Post by jpnullnvoid »

And the clouds parted...

That makes sense!

Thank you so much, Chris. I will try that.

John
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