slowing audio playback

Discussion in 'Recording/Live Sound' started by zenpicker, Jul 14, 2005.

  1. zenpicker

    zenpicker Member

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    I would like at times to be able to play my audio back at about half speed in order to isolate glitchy stuff and set in/out points more accurately. Yes, you can look at the waveforms and that's usually enough to go by, but sometimes it isn't decipherable enough. It would be so nice just to have a "half-speed" switch like they had on old tape recording units.

    I use Sonar, mostly, but have been tempted by Cubase (though put off by the price) and other editors. Since I do mostly audio that I record on a hard disk recorder (Tascam 788)--using MIDI only sporadically for percussion tracks--a MIDI-based solution isn't enough. I.e., I can just jack down the BPM setting and be done with it.

    Is there a way to do this in Sonar that I am missing, or can you do it in another editor? Seems like such an obvious need.
     
  2. TAVD

    TAVD Guitar Player Gold Supporting Member

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    Maybe not the solution you're looking for but have you tried changing the sample rate?
     
  3. zenpicker

    zenpicker Member

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    I wouldn't want to compromise the audio quality, for sure, but I'm not sure I understand why that would change the perceived speed of playback. I thought sample rate just governed how many times per second we record a data point from the audio input. :confused:
     
  4. TAVD

    TAVD Guitar Player Gold Supporting Member

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    I guess the best analogy I can think of is a record played at the wrong speed. You answered your own question really, the SR is a function of time. 96 khz = 96k samples/sec. If BPM is 120, then a 1/4 note = 1/2 sec or 48k samples. So, if you play your 96khz audio @ 48khz, your 1/4 note is now a 1/2 note.
     
  5. zenpicker

    zenpicker Member

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    Interesting. So if I follow you, I'd record at the highest resolution of which my equipment is capable, then decrease the bit rate in the software editor. But I can't do that, make my edits, and get back up to the original rate, can I? Isn't changing the sample rate a destructive edit?

    Pardon the dumb questions!
     
  6. TAVD

    TAVD Guitar Player Gold Supporting Member

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    Yes, SRC is destructive but not as bad as changing the word length.

    You wouldn't actually be doing a SRC in this case. You basically play the 96k track @ 48k, like switching a tape machine from 30 to 15 ips. In other words, you clock the 96k audio with a 48k source. Or import the 96k track into a 48k project.

    Does Sonar have a time compress/expand function? That will maintain the pitch.
     

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