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Variable speed change for audio

Discussion in 'Recording' started by info@soundcomposer.dk, Mar 2, 2011.

  1. info@soundcomposer.dk

    info@soundcomposer.dk Active Member

    I've spent a lot of hours trying to figure this one out but no luck so far.

    I'm editing a short film with a camera movement that speeds up really fast, almost stops and goes in slow motion and finally speeds up again at hits something. I want to illustrate this in the sound design. So I want to speed up a reverse/woosh sound and slow it down at the appropriate places.

    How is this easily done? I need like a speed curve that can work by speeding up the audio playback, slowing it down gradually, stopping, starting and so on.

    I've already tried in Final Cut Pro and Adobe Premiere, but they only work for the video. Not on the audio.

    Any help or suggestions would nice since I have a deadline soon

    Thanks in advance,
  2. natural

    natural Active Member

    Serato pitch n time, plugin, has a graph that can do that.
  3. Boswell

    Boswell Moderator Distinguished Member

    One way of achieving your aim is to use a pulse train to drive the external clock input of an audio DAC unit reproducing the audio. The DAC reconstruction filters need to track as well. You then re-sample the audio at a conventional constant rate appropriate for the video. Do you have a TTL pulse train with pulse frequency proportional to the required audio speed? Even an analog voltage that varies with speed would work through conversion of the varying voltage into a frequency.

    For this to work, you need a DAC unit that will continue to operate correctly when its clock is varied over a wide range. Not being able to find a commercial product in a hurry that would do this, I built one for a similar project many years ago.
  4. Big K

    Big K Well-Known Member

    Try this free plugin:

    [DLMURL="link removed TbT Tapestop - Virtual Effect[/DLMURL]

    Worked nicely for me for variable speed.

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