Tracks out of synch

[StratoPhish]

Hi - long time user, but gave up on the program because I couldn't resolve this. I'd love to get back into it if I can get some help with this problem. So, I joined this forum in the hopes that someone can point me in the right direction. I am a musician and use Audacity for multitrack recording - guitars, vocals,etc. I used the program successfully for many months, years actually, but I started to develop a situation on longer more complex projects where the tracks would start out synched perfectly, but as the project progressed the tracks wouldn't be playing together. It's not that they've shifted in time, rather it seems that one or more tracks are slowing down or speeding up slightly. Using 1.2.6 on XP. It's extremely frustrating putting 10-20 hours into a project only to trash it because this synch issue suddenly appears without warning. Any ideas please???

[steve]

Gradual drifting out of synch usually indicates that the sound cards clock signal is inaccurate (not stable).
This would affect all audio applications, though only noticeable with multiple tracks.

[StratoPhish]

Thank you. I assume the remedy for that is to replace the sound card?

[steve]

I prefer the term "upgrade" - it makes me feel better about spending money

If you are currently using a cheap, or on-board sound card, then it is very likely that this is the problem. If you're already using a high quality sound card that is designed for media work, then this is less likely to be the problem (as they are specifically designed to not cause this issue), in which case we may be better to start digging for other possible explanations before replacing the sound card.

I'm trying to think of a way that we can test the theory.

You could try this:
Generate a long click track - around the length of the longest project that you do.
Ensure that you have live monitoring of you microphone switched off or muted.
Play the click track through speakers, and record it back into Audacity with a microphone.
The two tracks should stay closely in synch for the duration of the recording. There may be a small off-set between the tracks (this can be corrected in Audacity 1.3.12) but the recording should not drift.

[angelfire]

Hi there,

you may have already tried this to my apologies if it's obvious or not appropriate.

If you look in the 'help' part of Audacity and look for 'latency test' it could be a latency problem with your computer, I had the same problem and just thought it was a problem with my computer soundcard processing speed etc - it wasn't that, it was the lag between the instruments/mics, leads and the computer.

I don't know, you may have already tried this and it doesn't work, it was just an idea.

If it is a latency problem, you need a cable with two mini jacks on either end so you can plug into your computer mic sockets.

Take care

Dan

[steve]

Thanks for your suggestion Dan, but latency problems result in tracks being a consistent amount out of sync, whereas the issue here is one of tracks gradually drifting out of sync. Details about latency issues are described in the manual here: http://manual.audacityteam.org/man/Latency_Test

[StratoPhish]

Thanks Steve (and Dan),

I did "upgrade" the soundcard at some point and as I mentioned it was functioning fine. I'm sure there are better / more expensive ones and I don't mind upgrading again but as I recall this wasn't the least expensive. I'll try to find time this weekend to run the test you suggested (interesting). I was wondering if the number of tracks might be a factor? Memory? As I recall it started on a complex project.