I’m using Windows Vista, Audacity 2.0.6, and have the .exe installer. My problem:
My friend records audio with Audacity which he then exports the audio so I can implement the recordings into my DAW. He noticed that the exported .wav files are slightly out of sync (about 1/8 a second I’d say) with the instrumental (created in my DAW) in which he recorded against. I thought it might have been the DAW improperly aligning the files, but if I open the same exported .wavs within the Audacity project itself, these files are also out of sync with the original recorded files (in multiple .au format, I suppose). Any ideas to the cause of this and how to rectify the problem so that the exported .wavs are exactly the same as recorded in Audacity? The exports used here are just the default uncompressed .wav; is there a certain encoding or header that we should be using?
This is also not an isolated problem; the same syncing issues have occured with three projects thus far.
When you record on a computer, it takes a little time for the sound to be converted to digital, work its way through the software and end up written to the hard drive. This “delay” is called “latency”. When recording along with a track that is playing on the computer, this delay can cause synchronisation problems unless it is dealt with. The way of dealing with the delay is to shift the newly recorded track a little to the left (earlier) so as to compensate for the fact that it gets written to disk a little late. This is called “latency compensation”. Fortunately, Audacity is able to automatically shift the new track to the left, but it needs to be manually set up so that the recording is moved just the right amount to compensate for the latency.
Thanks for the reply Steve! I actually don’t think the out of sync issue has to do with latency- I think my friend already fixed the discrepancies there as the recorded audio within the project sounds fine against the instrumental in Audacity, it’s just that when the recorded parts are exported, they sound unaligned. Anyway, I may have fixed my problem for the time being…sorry, I should have searched a little more thoroughly before posting. By looking at your and Gale Andrews suggestion in this topic (https://forum.audacityteam.org/t/alignment-probem-exporting-and-importing/33883/1) I was able to correct the unalignment issue- I just selected the recorded tracks in audacity and trimmed them -before- export. To make sure they synced correctly, I reopened the audacity project with the “untrimmed” tracks and the newly exported ones, and the correct alignment sounds to be preserved. I don’t understand why that worked logically, but it seems to be a solution for now…
Because latency correction is shifting the new track a little to the left, that can put the start of the track behind zero. When this happens it is indicated by small arrows on the left edge of the track as shown in the second track here:
If you export the tracks shown above, the first track will start at “time = 0.0”, but the second track starts a little earlier. Thus, when the tracks are imported back into Audacity or another program, the two exported tracks will be slightly out of sync.
Trimming all tracks so that they all start at “time = 0.0” resolves this issue.
We have a “feature request” listed that you may wish to vote for: “Preserve start-time relative to time zero when exporting”
That feature would remove the need to mess around trimming or padding the start of tracks and ensure that they line up correctly when exported for use in another program.
