Hello everybody. I did some research on the forum and couldn’t find any help, I think my problem is very specific. Here we go: I’m using Audacity 2.1.2, and used to use the 2.0.2 version with Windows 8.1. I have a solo project and use my laptop to play live, with drums and harmonies coming from Audacity while I play guitar and sing. Sometimes, the tracks get out of sync while playing , which is a very bad thing to happen in front of people as you all can imagine. Somebody already had this problem, or knows what I can do to prevent it? Thanks.
I have a solo project and use my laptop to play live, with drums and harmonies coming from Audacity while I play guitar and sing. Sometimes, the tracks get out of sync while playing.
I assume the drums & harmonies are getting out-of-sync with each other, since it’s up to you to keep your guitar & live-voice in sync with the backing tracks?
I don’t know why that’s happening but [u]mix[/u] the backing tracks together and render (export) to one stereo (or mono) WAV file.
which is a very bad thing to happen in front of people as you all can imagine
Since computers are the least reliable things we own, make sure you have a backup computer set-up and ready to go whenever the computer is a critical part of your live performance… And, carry extra guitar strings and a spare guitar cable & mic cable too! 
I assume the drums & harmonies are getting out-of-sync with each other, since it’s up to you to keep your guitar & live-voice in sync with the backing tracks?
You can hear whats happening clearer in the rhythm: the tracks of bass drum and snare, for instance, which are perfectly in sync and being played, become a mess out of nowhere, with the snare over the kicks or after, and it craps out completely. If went I stop and play again, the problem is gone. It’s very frustrating coz’ I don’t have the slightest idea of what to do. Could it be interference from the amp heads, speakers, or even the high volume of them? And if so, it would be interference with Audacity, since I went thru this with two different laptops? I don’t know… 
I don’t know why that’s happening but mix the backing tracks together and render (export) to one stereo (or mono) WAV file.
I did it in the past, to play form other(and compact) sources, like MP4the, but started to use the laptop with the open mix in Audacity, so I could mix it in each live situation,and even with the song rolling if needed, haha. But I’ll do as you said, using better the soundchecks to equalize every detail and rendering a single track.
DVDdoug, thanks a lot!
Could it be interference from the amp heads, speakers, or even the high volume of them?
No… It’s something “digital” inside the computer. Usually these problems are related to multitasking… A certain task doesn’t complete in time and and an input buffer overflows before it can be read or an output buffer underflows (“runs dry”) before it can be re-filled and you get glitches & timing errors. Note that your operating system is multitasking (updating the clock & display, checking the mouse 7 keyboard, and a bunch of other stuff, even if you’re only running one application. Usually it’s not the case that your computer isn’t fast enough (although a faster computer usually helps), it’s just that one (or more) of the little tasks is taking a little too long…
And, if you’ve got separate files for the harmonies, snare, cymbal, etc., your hard drive’s read head has to jump all over the place as it tries to read all of your files at the same time. If that’s the problem, a solid state drive should take care of it. (Or, simply defragmenting your drive may help.)
[u]Here is an e-Book[/u] about optimizing your computer for audio.
I did it in the past, to play form other(and compact) sources, like MP4the…
Sorry, i don’t know what MP4the is.
…
but started to use the laptop with the open mix in Audacity, so I could mix it in each live situation,and even with the song rolling if needed
Audacity is a non-linear audio editor that’s designed to work on digital audio files. it’s not intended for real-time or live use. I’m not saying you can’t make it work, but that’s not what it’s made for.
Once you’ve got your mix done in Audacity, I’d recommend regular player-software (Windows Media Player, etc.) for playing the backing track during your live performance.
I’ve heard of people using a DAW (REAPER, CUBASE, Sonar, etc.) for live mixing. But, I’ve also heard of a few that have had ruined shows and then they go back to good 'old hardware mixing. 
IMO - You shouldn’t be mixing your backing tracks live, especially if you’re trying to do it yourself while you should be focusing on performing. You may have to adjust the blend between the live and recorded tracks, but the recorded tracks should be done and perfect.
No… It’s something “digital” inside the computer. Usually these problems are related to multitasking…
Yeah, it’s an obvious thing, but it didn’t come to my mind, haha. I downloaded the E-book and already applied its content to my laptop. Let’s wait to see the results.
DVDdoug, thank you very much for all the help!