Audio Track Lag

How to document for other editors?

If I record a new audio track while playing back existing audio tracks, n-Track adds in an offset to the new track to compensate for the lag between what I hear and what is recorded so the newly recorded track plays back in sync with the existing recorded tracks. This makes sense, but if you wanted to import all the tracks into another multitrack editor, the actual wave files on the disk do not have the offset and they will play out of sync.

To illustrate. Record about ten seconds of audio on track 1. Play back track 1 into a speaker or headphones that will be picked up by your microphone and record the played back sound into track 2. When you play back both tracks they will be in sync. But, if you look at the actual wave files on the hard drive using an external editor, track 2’s wave file will have a longer overall time than shown by n-Track because there will be silence at the beginning equal to the lag of your soundcard’s recording versus playback. So, if you imported both track 1 and track 2’s wave files into another multitrack editor they will be out of sync.

My concern is if I ever move from n-Track to another program, I want to be able to import the archived wave files of all my song tracks into the new program and have them be in sync. Since the lag offset seems to be kept in the .sng file, there is no way other than a lot of trial and error trimming to get the files lined back up. It would be nice to have the actual offset for each track shown, perhaps when checking properties. Or, better yet, a way of printing out and saving a .txt file of all the tracks and their offsets.

I mention this because I recently moved from PowerTracks Pro Audio to n-Track and only had to export the tracks to wave files and import them into n-Track and everything was in sync. All I had to do was add the same effects and adjust volumes and I had the same resulting mixdown as I had in PowerTracks. But if I ever wanted to move from n-Track to another program, or send my wave files to another person, those wave files I recorded while listening to existing files in n-Track will be out of sync.

I welcome your comments and ideas.

Hi I did the same tests as you a while ago and the second track was about 2 m/sec at (44K 16 bit) behind the first one which was not enough to cause any problems. Mostly due I would guess to going through a D/A then an A/D conversion. This would make the second track longer but only by a fraction.
How far out of sync are the tracks if loaded into another program?

Nick

Typically the second track is about 600 to 800ms longer.

Is the 600ms to 800ms difference normal, or is there something about my particular setup that is causing the difference?

I am wondering if most n-Track users have this difference in track times but are not aware of it because n-Track seems to automatically clip off the extra lead time in newly recorded tracks so the wave file showing in the track is properly lined up with the other previously recorded tracks. What would be helpful for me is to know if the time difference I am experiencing is typical, or caused by something in my particular setup. I would appreciate hearing from more of you on this.

I just did the same test myself and the difference is not noticeable.
When I zoom right in the difference is less than 1 frame (at 30fps)

Here’s a screen shot as an example Screenshot of lag

It might be something to do with your buffers, I’m not sure…
What are you buffer settings at?
Also what driver are you using for your soundcard?

Rich

I have exported back and forth between ntrack and a couple of other programs and haven’t noticed a lag.

The programs I use mostly are ntrack, Powertracks and Kristal.

I seem to have found the solution to my problem, though I will wait to see if it stays “fixed” to be sure it is the permanent fix. I unchecked “Keep audio devices open” in Wave Devices/Advanced and that dropped the lag time to almost zero. If I recheck the “Keep audio devices open” box, the lag returns. Actually, I prefer keeping the box unchecked because I want to be able to run other audio software while n-Track is open and if the box is checked, n-Track won’t let go of the soundcard. I don’t know why it makes a difference, but keeping the box unchecked certainly fixes the lag problem for me.