Help: glitches when recording cassettes to CDs

Discussion in 'Macintosh Computers' started by notjustjay, Oct 21, 2003.

  1. notjustjay macrumors 603


    Sep 19, 2003
    Canada, eh?
    Hey guys! I'm hoping maybe some of you can give me a hand with a problem I'm having. I've been tasked with burning audio CDs from a bunch of audiotapes from a conference. I record from a tape player (boombox, walkman) into the line ins of my 12" Powerbook (1 GHz, 512 MB, 10.2.8).

    I'm having a problem: the audio I record has pops and strange electronic-sounding glitches, they sound almost like dropouts from a cell phone conversation.

    Here's a sample:

    (It's a preacher reading some scripture.. listen particularly to the first 10-15 seconds and the last 10 seconds for the biggest glitches)

    It's not my audio program, because I've used a bunch: Audio In, Audio Recorder, Spark ME, all with the same results.

    It's not my cassette, because it sounds fine when I listen to it myself. And, when I re-record the same section of the tape, glitches happen in different spots!

    It's not my tape player, because I've tried it with several and they all do the same thing.

    It's not the line in, because I can record from my iPod with no troubles at all. I can also record using the built-in mic just fine.

    FINALLY, (and this one is what hurts the most!) -- if I do the same thing with my Windows laptop, I get a perfect recording with NO glitches. That is what I've been using to convert the first few tapes... but I want this to work on my Mac!

    Weird?! Any ideas?
  2. pepeleuepe macrumors 6502

    Oct 27, 2002
    Los Angeles, California
    Double check the sample rate and bit rate that you're recording at and make sure its the same as the one you're playing it back as. For example, CD's should be recorded at 44.1 kHz 16-bit. This sounds like it might be a sample rate conversion problem. Also try recording the audio at 22 kHz, which is standard for a tape, then converting those files to 44.1 kHz. Not sure why it wouldn't be working the way you're doing it, very odd problem. Anyway, make sure you test your cables, jacks, and try it again.

    Let me know if any of this helps.
  3. FatTony macrumors regular

    Jul 17, 2002
    I do this very same thing all the time. In fact, I wrote a flash app that will sync the audio with exported jpgs from PowerPoint for presenting on the web. I've never had a problem.

    It sounds like you have done a ton of troubleshooting already, so the only thing I can think of is maybe trying a different version of quicktime. If you haven't upgraded to the latest version (6.4), do that. If you have, try reverting to the original version that shipped with your PowerBook.

    Good luck and let me know if quicktime is the problem.
  4. notjustjay thread starter macrumors 603


    Sep 19, 2003
    Canada, eh?
    thanks for the suggestions, guys.

    I'll try a different sampling rate. Never thought of that, worth a shot.

    I haven't really had too much time to troubleshoot this, since I'm kind of on a deadline with these tapes so I'm using what works (i.e. the Windows computer). I just feel a need to figure out what this problem is.

    It seems strange to me, because as you can hear from the sample, MOST of the recording is perfectly fine... but every so often there will be a totally unintelligible "dropout". And there are subtle pops throughout the recording, though these I would have been happy to live with.

    At first I thought it was a bad tape, because I have heard very old tapes "dropout" like that, but the tape plays fine. And the dropouts don't happen in the same spots.

    I'll try upgrading my QuickTime too, see if that helps. I'm still on 6.3.

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