VideoHelp Forum
+ Reply to Thread
Results 1 to 8 of 8
Thread
  1. Member
    Join Date: Aug 2014
    Location: United States
    Search Comp PM
    I have searched around on the forums for a solution to my problem, but I haven't found a similar one to my particular problem. If you know of one, please let me know!

    My problem is that I am recording audio from up to 6 different sources for long a duration (usually around an hour) and up to 6 videos with audio. To help with the syncing problem, each audio track is recorded with the exact same mic (Blue) into Audacity with the same project rate (48k) then exported with the same settings. Despite this, even after about 10 minutes a slight echo becomes audible and only get worse the longer it goes. I suspect the problem may be that the audio is recorded to different computers with a wide range of brands and hardware. I sadly do not have the capability to record them to the same device.

    The only solution I have found is to put them in Adobe Audition and fractionally change the rate of each one. (Usually by .02% or something similar) I have to do this very frequently and it takes a very long time to add 6 one hour clips to the program then render it. Ideally I'd like to be able to fix it from Abobe Premiere, but it does not have the precision required to do something like this, at least from what I know about the program.

    Is there any program to quickly sync the audio files? It would be a huge time saver. Or am I just missing something dumb? A plugin for Premiere? Any help is greatly appreciated.
    Quote Quote  
  2. Member Cornucopia's Avatar
    Join Date: Oct 2001
    Location: Deep in the Heart of Texas
    Search Comp PM
    I don't follow: what do you mean by "each audio track is recorded with the exact same mic into Audacity with the same project rate..."

    WHAT is being recorded? Someone singing? a playback of a pre-produced track?

    How do you know there is ECHO? Do you combine those tracks again after export?

    Be clearer & more detailed with what's going on here. Once you are, I think I can help.

    Scott
    "When will the rhetorical questions end?!" - George Carlin
    Quote Quote  
  3. Member
    Join Date: Aug 2014
    Location: United States
    Search Comp PM
    Ah sorry! What I mean it is the same microphone model. I bought 6 of the same microphone. What is being recorded is someone speaking directly into the mic. 6 people are talking into individual microphones at the same time, similar to a podcast. I hear the echo when I play the audios together in Premiere. There is a clap at the beginning to precisely sync the multiple tracks. After doing this they slowly fall out of sync of each other as it goes on. I hope that's more clear! Let me know if there's anything else I can clarify. Thanks for the quick response.
    Quote Quote  
  4. Member Cornucopia's Avatar
    Join Date: Oct 2001
    Location: Deep in the Heart of Texas
    Search Comp PM
    Where are these mics placed WRT each other? How & where is the "clap" generated"?

    Again, HOW do you know they're falling out of sync? Are you trying to edit them together in a multitrack NLE or DAW?

    Scott
    "When will the rhetorical questions end?!" - George Carlin
    Quote Quote  
  5. Member
    Join Date: Aug 2014
    Location: United States
    Search Comp PM
    The mics are placed a few feet apart from each other facing a similar direction. The clap is made from a basic/cheap clapperboard. I am trying to edit them in a multitrack NLE. In Adobe Premiere, after syncing all the clips to the original clap, I hit play on the preview, which plays the video and all the audio clips. Listening to this it seems the clips are losing sync (creating an echo effect). I don't know that they are losing sync in any other means then listening to them in the multitrack NLE. I'm sorry I don't know how to make this more clear. Hope this cleared a few things up.
    Quote Quote  
  6. Member Cornucopia's Avatar
    Join Date: Oct 2001
    Location: Deep in the Heart of Texas
    Search Comp PM
    "The mics are placed a few feet apart" = ECHO.
    Unless the mics are all in a circle, with their distances ALL exactly equal (to the clapper), the relative distances from the clapper will mean relative timing differences. Your attempt to put them IN SYNC has ensured actually putting them OUT of sync.

    Also, unless you are simultaneously recording them ALL THROUGH THE SAME A/D mechanism bank (or combos of units that are "genlocked"), and to the same PC, you are creating many variations on your "48k" sample rate. Very minor, to be sure, but not EXACT. With that in mind, it is no surprise that they will fall out of sync (progressively, esp. after 1 hour's time).

    Either re-record with a more uniform setup as mentioned, or you'll have to manually edit them (snipping out little bits occasionally & sliding them to get them back in line with the rest).

    You could also have done, not just a starting clap but an ENDING clap. That way, if you find that they are progressively out of sync, you can do a fairly simple time-compression on them to get them back into sync. This won't, however, make them remain fully in sync throughout (as there would be minor fluctuations), but at least then you can be assured that overall it is extremely close and that the start & finish ARE in sync.

    Using a uniform setup costs $$$. Examples would be ProTools' HD-IO interface: http://www.avid.com/US/products/HD-IO.

    Scott
    "When will the rhetorical questions end?!" - George Carlin
    Quote Quote  
  7. Member
    Join Date: Aug 2014
    Location: United States
    Search Comp PM
    Okay thanks for the patience and help! I'll use this knowledge in the future. I'm surprised with the incredible ways you can edit audio now that there isn't a post-production solution to this.
    Quote Quote  
  8. Member Cornucopia's Avatar
    Join Date: Oct 2001
    Location: Deep in the Heart of Texas
    Search Comp PM
    This is the kind of thing that separates the pros from the hobbyists & consumers...

    Scott
    "When will the rhetorical questions end?!" - George Carlin
    Quote Quote