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Pro tools audio slow down help

Discussion in 'Pro Tools' started by jurassicpark, Jan 20, 2011.

  1. jurassicpark

    jurassicpark Active Member

    Hi, this forum's been a great help to me so far so I thought I'd consult again:

    I have a problem with the audio I record playing slow once I've burnt it to cd and then play in my cd player.

    Here's what i do to get it onto cd:

    Once all is recorded, I apply any effects/eq/compression and mix it to a submix.
    Then I apply the Powerdither to the main master track (16bit)

    After this I bounce to disc where I'm asked to specify the bit rate (16) and khz (41000) and convert it to a wav file

    Now I burn it to CD audio in Toast.

    When i play it on a cd, it's slow. When i play it from CD in my mac on Itunes it plays ok.
    Is there something wrong with the process I'm doing/ something wrong with my cd burner?



    ALSO, I've just got hold of a behringer v-amp pro for silent late night guitar recording. How am I best connecting it to my digi 882 interfaces?
    I have 3 digi 882s daisy chained into a digi MTP AV (but honestly don't really understand midi!! - it's next on my 'to learn list')

    Darren
     
  2. Boswell

    Boswell Moderator Distinguished Member

    Try specifying 44100 Hz and not 41000 Hz as your sampling rate in the bounce step.
     
  3. jurassicpark

    jurassicpark Active Member

    TYPO, sorry, it's always set to 44100.
     
  4. jurassicpark

    jurassicpark Active Member

    Also, I've tried with and without the dither plug-in on the mastering track on 3 different compositions. It must be in the bounce stage, right?
     
  5. natural

    natural Active Member

    Have you tried a different CD player?

    Everything you're doing seems proper.
    This is not a common problem, so it's going to take a little detective work to find out where the problem is.
    And just for fun, How much slower is it? (BPM) and is it just slower or also lower in pitch?
     
  6. mdb

    mdb Active Member

    To connect the Behringer to the digi, use the analog line outs and connect them to your digi 882 analog inputs (1&2, 3&4, etc.). It should be that simple. Adjust the gain on your Behringer and in the software mixer & DAW.

    Not sure about your other question although it shouldn't slow down the original track during CD Burn. Try dumping the song to CD via iTunes rather than using Toast. You can put the *.wav or AIFF file into iTunes without it converting to *.mp3
     
  7. TheJackAttack

    TheJackAttack Distinguished Member

    The slowdown is going to be in the conversion to 44.1k. Test a project by recording the whole thing in 44.1k instead of 48k.
     
  8. mdb

    mdb Active Member


    Can you elaborate on why? I don't see how degrading the sound quality would actually slow down the temp of a track. I record at 48K and downsample to 44.1K without any issues. If it does do this and I've just never noticed it I would like to understand why it does it.
     
  9. TheJackAttack

    TheJackAttack Distinguished Member

    This an issue where the sample rate was not converted but simply changed.
     
  10. mdb

    mdb Active Member

    Ah, yes that can definitely cause that if that's what's happening, but I thought you could only do that within the DAW. I did it once after recording at 44.1k and decided I should have recorded in 48K so I changed it directly in the project file. Surprise!! I was learning then... still am. When converting to 44.1K during bouncing I don't think it should cause a slowing down of the track. From how I'm reading his post, the problem is that it plays okay in iTunes, but not on a CD player after the bouncing process. That seems odd.
     
  11. TheJackAttack

    TheJackAttack Distinguished Member

    Some programs read the speed/sample rate of the file before they play them. Some programs play music and DVD's at their respective defaults for the soundcard itself. That is the most benign example. There is also the syndrome where a file is for example recorded at 48k and then the header is changed accidentally or manually so that the actual "musical" portion is described by the header as 44.1k. There is no way to tell what is for sure going on without looking at it personally. Any DAW is capable of sample rate conversion. Some do it better than others, but it is also possible to change the bit rate without resampling and this is what I think happened. At any rate (ha), it is always best to record at target sample rate or multiples thereof.
     
  12. mdb

    mdb Active Member

    Okay then. I guess the way I do it works and I'll have to do some more studying. You seem to understand it well. :smile:
     
  13. jurassicpark

    jurassicpark Active Member

    That's correct. I'm going to try all of this tomorrow on a completely new track and I'll update with the results. If I'm still having problems, I might post a track to some drop box somewhere for you guys to look at....this is really helpful. Thanks
     
  14. RemyRAD

    RemyRAD Guest

    Let's first try to establish whether it is playing slower & lower in pitch? Or whether it's playing slower at the proper pitch? One is controlled by sample rate. The other is controlled by sample rate down-conversion. It's the same but different. Just as much as it is different from the same.

    You are most definitely converting it from 48 kHz to 44.1 kHz without downsampling it from 48 kHz to 44.1 kHz if it's both slower & lower. It's a simple mistake. It's okay, we've all done it at somewhere along the line in our digital escapades since the early 1980s. You have to admit, it's always good for a laugh.

    OK

    A funny little story here I'll share with everybody. I'm a bit chagrined to admit this however....

    Back in 1987, I purchased one of the first portable DAT recorders I could find. Believe it or not, it was a Casio, as in cheap watches, entry-level synthesizers. Well, it was simply horrible sounding. Now I can't quite remember whether it was switchable from 44.1 kHz to 48 kHz? I can tell you it had no dither and everything faded into a cwispy-crunch. It went back to the factory. There went back to the factory again. It was replaced. I had to return it, it was just too horrible and along came the Panasonic SV 3500. Around 1996, I finally got my first CD burner. I still had the Panasonic SV 3500 DAT recorder. This was some very nice jazz. Throughout the years, I've never been certain whether I transferred it properly? It sounds great at either 44.1 kHz or 48 kHz without any up or down conversion. Meaning, it's playing higher and faster or lower and slower. The analogy here is that I've simply changing speeds on playback. What you're missing is that you need to "down convert" it instead of merely changing the sample rate which would make it play both higher & faster or lower & slower. As was mine. Thankfully, both ways sound spectacular with this entire 2+ hour performance. The original DAT had long ago been copied and unfortunately destroyed. So what I think is a 44.1 kHz copy might be a 48 kHz copy transferred to 44.1 kHz to CD? I love it both ways. It's whatever works. There was no singing and even the few countdowns you can hear the drummer do does not give one the proper perspective as to which 4-3-2-1 countdown is the right pitch? His voice sounds normal either way. I've no way of actually knowing what keys each song was intentionally performed in? So, I have 2 CDs. One with a slightly more up-tempo and brighter feel. The other with a more refined, mellow laid-back feel. Which to choose?? Don't ask me no questions and I'll convert for you no lies. I just wanted to be clear on what I'm not being clear about.

    Yes I'm embarrassed. Yes I'm blushing. It's a woman's prerogative to make mistakes unlike men.
    Mx. Remy Ann David
     
  15. jurassicpark

    jurassicpark Active Member

    In 'session set-up' the details for the session are as follows:
    Sample rate: 44.1khz
    Bit depth: 24 bit
    Audio format AIFF

    In 'hardware set up' the digi 882s are set at a sample rate of 44.1khz

    In 'preferences' > 'processing' the audiosuite dither us set to 24 bits

    Does this help?
     
  16. natural

    natural Active Member

    Not really,
    Both Remy and I have asked for more info regarding speed and pitch. (how far off is the speed, how flat is the pitch)
    Additionally I asked if you have tried a 2nd CD player. I suspect a problem with the CD player since that's the only place where the Cd does not play properly. So that needs to be ruled out first. (and it's a simple test)
    Another way to test it would be to take a commercial CD and play it in both the CD player and the computer. Are there any differences there?

    If the CD player is fine then my next question would be, do you have a MOTU midi time piece (or similar device) also connected to the 882 clock?
     
  17. TheJackAttack

    TheJackAttack Distinguished Member

    What Thomas said. And your mixdown bit rate should.be 16 bit for CD not 24.
     
  18. jurassicpark

    jurassicpark Active Member

    The CD player is fine as the cd plays slow on 3 different machines.
    I do have a digi MTP connecting my 882s, they're running as slaves. To be honest, this is how I bought it and I haven't ventured into this area as I don't know much about midi (that's next on my very long list!)

    Jack Attack - I think the mixdown bit rate is 16 bit....the 24 bit setting on the dither is telling it what bit rate the files currently are (I think??)

    Thanks for all your help guys, this is a real steep learning curve but a fun one!
     
  19. natural

    natural Active Member

    Well, the MTP can become your master clock depending on your settings.
    This doesn't explain why the CD will play fine on the computer however.
    No, wait...
    When you're playing the CD on the computer is it also going back through the Digi hardware?
    If so, we might be on to something.
     
  20. jurassicpark

    jurassicpark Active Member

    erm, maybe. To be honest I don't know how it's routed.....except it's coming through my studio monitors that are fed by outs from my digi 882
     

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