Off-Center Filter

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Audacity 1.3.x is now obsolete. Please use the current Audacity 2.1.x version.

The final version of Audacity for Windows 98/ME is the legacy 2.0.0 version.
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LaughingOtter
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Off-Center Filter

Post by LaughingOtter » Sat Jul 23, 2011 3:06 pm

Hi!
I've been using Audacity for the better part of the last year, about time I joined up with the experts!
Mostly I've used Audacity for processing and clarifying speech clips lifted from pinball ROMs and very old CD-ROM games.

I'm looking to torture some Goths with some really bad music.
I thought nothing could be worse than "It's A Small World" played as if on vinyl with the hole drilled about 1/2 inch off center.
So obviously this would be along a sine wave related to the playing speed.
How could I simulate this in Audacity? Or perhaps this could be a Nyquist programming exercise?
I know there are threads dedicated to removing such effects, but none for actually inducing this effect.

It takes all types, eh?

steve
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Re: Off-Center Filter

Post by steve » Sun Jul 24, 2011 12:43 pm

A slow "vibrato" effect will produce the required effect.

The vibrato speed needs to match the rotational speed of a record, so for a 45 RPM record that would be 45/60 = 0.75 Hz.
I don't know of a Vibrato effect that has been officially released, but attached is an experimental effect that can produce the effect (not yet released, but should work OK - back up everything before using the effect just in case).

Try settings of:
Function: Vibrato
Mod shape: Sine
Initial speed: 0.75
Final speed: 0.75
Initial depth: 20%
Final depth: 20%

See here for installing plug-ins: http://audacityteam.org/download/plugins

You are the first person to test this plug-in (apart from myself) so please write back and say how you get on with it.
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LaughingOtter
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Re: Off-Center Filter

Post by LaughingOtter » Mon Jul 25, 2011 11:12 pm

This is perfect! Exactly what I was looking for!
Your math is good too, though sliding the Initial and Final Depth values to 100% produces exactly the effect I was looking for!
Truly ghastly.

The Tremolo effect works the same as the Tremolo plugin, but the plugin seems to have more detail

And with the sliders all up on maximum on Vibrato you have a very warbly and blurred version of the original. Sounds almost like just before the casette player ate the tape.

Definite Potential!
More to follow. Gonna play around with this some more.

Thank you again, Steve!
Steve

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