Samson C01U commentary becomes desynced slowly over time.

Hey guys. So, this is a problem I’ve been having ever since I bought my Samson C01U condenser mic. I record game playthroughs and put them up on Youtube, with my commentary over it, like lots of people do. However, my commentary footage, which I record with Audacity slowly becomes more and more desynced the longer I play. This never used to happen when I was using headset microphones, but for some reason happens now that I’ve upgraded to a better audio setup.

I’m here today to try and find out what can cause such an issue, and hopefully find some ways to fix it. I made a video showing the desync, as well as some of my Audacity settings, which can be seen here:

http://youtu.be/I1AMrTAu_LQ


The version of Audacity I’m currently using is 2.0.5.

My Samson C01U is connected to my computer via USB cable, into a USB 2.0 port. My computer specs are as follows:

OS: Windows 7 64bit
CPU: AMD FX-6300 6-core 3.5GHz
RAM: 2x4GB of PC1600 DDR3
PSU: 500w
GPU: GeForce 560 GTX

If anybody out there who is more well-versed in audio setups than I am has any ideas as to what can create such a problem, I would be most grateful to hear your suggestions. Also, if you require more information from me, I’ll be more than happy to give it. Any help at all you could provide would be fantastic. Thank you in advance!

When you were using the analog headset, the digital clock was generated by the computer which, we assume was also generating everything else. The Samson microphone generates digital sound independent of the computer, and since all clock systems have manufacturer’s tolerances, they drift.

If the drifting voice track is divorced from the show sound, you can sync it back up again with Effect > Change Speed. If the two are the same track, you’re hosed.

People who are desperate to combine two USB microphones in the same computer have the same problem. You can do that, but on some machines you get a message: “which one do you want me to use as the master.”

Because it can’t sync to both.

Koz

Interesting. I’ll have to do a test and check out that change speed setting when I get off of work. However, wouldn’t the change speed setting make the audio towards the beginning of the track a bit out of sync? I say this without any knowledge or testing this setting out for myself yet, but I don’t have the time to test it right now, unfortunately.

Luckily, my recorded voice from the C01U is completely separate from the video game audio, so Change Speed should work. I’ll have a look once I return. Thanks for the insight! :smiley:

As Koz wrote, it is very common for different devices to run at slightly different rates. Professional studios can get round this by using (expensive) hardware that can all be connected to one common “word clock” (http://en.wikipedia.org/wiki/Word_clock)

Provided that both the computer and the microphone are running at consistent speeds (the speed does not vary over time), then it is easy to accurately stretch an audio track to a precise length (in seconds) using this plug-in: http://forum.audacityteam.org/download/file.php?id=10288
For more information about the plug-in (and another more complex version), see this topic: https://forum.audacityteam.org/t/change-speed-stretch-audio-to-a-specified-length/23332/1

And not to leave anything out, If the two tracks are off the same amount beginning and end, you can use the Time Shift Tool (two sideways black arrows) to shove them back into sync.

Koz

Thank you guys, VERY much! And thank you for showing me that stretch audio plugin. I went ahead and installed that and tried it on an hour and a half test sample. I shrunk my voice audio down by a little more than half a second, and it was pretty much in sync both at the beginning and the end. Longer play sessions obviously will require a bit of fine tuning to get the timing right, but before long I’ll just ‘know’ by how much my voice audio track needs to be shrunk down by based on how long the gameplay recording is. So that’ll get easier over time.

Thanks again guys, you were a big help!

Most hardware stays put, so as long as you don’t change anything serious, the error should be constant.