Recorded tracks play back at slower speed

[ChrisHarding]

I've just fixed the latency thanks to another thread here, but I am still getting this problem. It's hard to explain this, so I'll try and descrie it in terms of "Track 1" and "Track 2".

I record track 1, then I record track 2 playing along to track 1. However, when I play back both, I discover that they are not aligned. I can't work out which is which, but either track 1 is playing back too slowly, or track 2 is playing back too quickly. I get the same effect when track 1 is a click track.

What could this be? Thanks!

[Spider-Skot]

Hello. Name's Skot, and this is my first post here. I'm having the same problem as the first poster. I fixed my latency issues using the click track method in the other help thread. I made a 16 beat click track at 120bpm. They now start out at the exact same time upon playback, but by the time it reaches the 16th click, the second track is actually 50 ms ahead of the original.
I've included a screencap to demonstrate: (note...the caption says track 2 is lagging at beat 8, but you can see it's actually ahead at beat 16. I smurfed up )


I write a lot of music with tracks that need to be aligned perfectly (metal riffs, ya know) and this is kind of annoying. Anyone??

Skot

Edit: I just did some experimenting, recording the same click via the same method four different times on four seperate tracks, and the lag is slightly different every time, only by a millisecond or so, but that'll add up over the course of a six or seven minute song. HELP!!

[steve]

You would expect digital to stay in time and run at a constant speed wouldn't you. Unfortunately this is not the case as it depends on the accuracy of the clock signal that the sound card uses.

On my "SoundBlaster Live value", I get a "drift" of about 0.0000005% (if I've worked out the number of zeros correctly) - about 1 ms per 2 minutes, which is acceptable for me, though it gets worse the more tracks that I have and increases to about 1 ms per minute with 6 tracks playing (Pentium 500, Win XP).

You don't mention what your soundcard is, but my guess is that the problem is there.
If you are using an onboard sound card, you could try checking in the BIOS to see if "spread spectrum" is enabled - I don't know if that will make any difference, but it may be worth checking.

[Spider-Skot]

Thanks for the reply, Steve. I went ahead and tried recording a full-length song (8 minutes, 6 tracks so far) with the latency settings the way the other thread described, and it turns out the lag is small enough as to be virtually unnoticable. I'm such a perfectionist, I guess I just unrealistically expect the computer to be perfect too and nitpick any discrepancy...lol. My soundcard shows up as Realtek AC97. The PC is an almost 6 year old Wal-Mart HP, so I guess I shouldn't expect too much

Thanks again. I like this version of Audacity better than 1.2, and besides, it doesn't crash every time I try to do something!
Later!
SKOt