44k thinks it's 48k chipmunks

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johnsh
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2011/04/03 17:57:15 (permalink)

44k thinks it's 48k chipmunks

Gear: MOTU 24i, Sonar 8.5 Producer, intel core 2 quad processor, 4gb ram, Windows 7 64 bit
 
Settings: New files at 48k, 24bit
 
I created a new file at 48k, 24 bit and had a session that I was ready to record. They wanted to hear something on youtube and so I navigated to youtube and played the song off of youtube. I have my computer using the same audio interface as Sonar and to play the song from youtube it bumped the sample rate on my motu 24i to 44k. After playing the youtube song I then changed the focus to Sonar and clicked R for record. When we listened to the recording that night it sounded fine.
 
A week later we got together to mix it down and when we played it in Sonar it sounded a bit like the chipmunks. I had Sonar up and looked at the motu sample rate and it was at 48k and the status bar in Sonar displayed 48k and 24 bit. After thinking about it I brought up youtube and played a song and watched the motu and the sample rate on the motu changed to 44k. I stopped the youtube song and went back to Sonar and when I hit play the audio sounded correct. This was with the motu set to 44k.
 
I checked the audio files properties and the audio files think they are 48k files but they should be 44k files. Is there a way to modify the data associated with the audio file so they think they are using a 44k sample rate instead of 48k? If it's not a huge job I'd like to fix this situation.
 
Thanks,
 
John Holmes
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#1

3 Replies Related Threads
    lfm
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    Re:44k thinks it's 48k chipmunks 2011/04/04 01:48:21 (permalink)
    #1. Why don't you just export it setting as 44.1khz?

    Sonar will convert it for you. Yes, I know you don't want any conversion, but it might be that Sonar just forgets to mark to file correctly.

    Will it sound right then?

    #2. Look up the file Sonar is storing the recording in and play and see if it sounds as it should.


    #3. If it doesn't I would import it alone to another project set to 44.1 and see how it plays and then export again.

    My guess is that either of these two ways would fix it.

    #4. But the hacker style would be possible to patch the header thinking it's 44.1. But if there are tools to do that or if you have to actually read specs for wav files I don't know.

    I had similar problems but with external digital audio sources through spdif.

    #5, Are you having more than one soundcardin computer?
    It might be that the source for sync is set wrong in Sonar. I mean when playing through browser if is using the internal soundcard, if windows is not set to use the MOTU as well.

    Just a bunch of ideas...
    post edited by lfm - 2011/04/04 01:51:26
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    tarsier
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    Re:44k thinks it's 48k chipmunks 2011/04/04 10:15:57 (permalink)
    This sort of thing has happened to me before. The easiest solution I found was to load the audio files into Adobe Audition and use its 'adjust sample rate' feature to set the files to 44.1, and then sample rate convert back to 48.  Then load the files back into Sonar.

    I'm not sure which other audio editors have a feature similar to 'adjust sample rate' which only changes the sample rate info in the audio file without sample rate converting.
    #3
    johnsh
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    Re:44k thinks it's 48k chipmunks 2011/04/05 13:00:52 (permalink)
    I did some research and found that I could open a .wav file in a Hex binary editor. Once I knew the format of the wave file Header after doing some google searches I was able to do a mixdown of the file at 48k, 16 bit and then edit the file in the Hex editor and change the sample rate to 44k. Then when I played the file it sounded correct.
     
    The Hex representation for 48000 is BB80 and for 44100 is AC44. It's basically 2 bytes in the file. It ended up being a very easy solution. I downloaded HexEdit at this link: http://www.mitec.cz/hex.html and opened the file and the 13th group of 4 Hex numbers (25th and 26th byte) contain the sample rate. It will be 44AC for 44k and 80BB for 48k.
     
    Anyway, I got my problem solved and learned something... thanks for the responses... john
     
     
    #4
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