Audacity Forum

Hi
I am using Audacity 1.2.6 with Samson CO3U USB microphone to record separate voice and keyboard tracks. On playback, there is a clicking sound interference and the tempo is not consistent, the track marginally, but noticeably, speeding up and slowing down, according to input volume. Have tried different input levels and microphone modes. Does anyone recognize these problems?
Many thanks
Davslov

It sounds to me like your computer is struggling to keep up with the recording process. I had this type of problem constantly with a PII 500 running Xubuntu - switching to the rt-kernel fixed the problem for me.

Hi, really appreciate your reply. I'm running Vista Home Premium, Core2Duo processor E4500 @ 2.20Mhz with 2GB RAM, so would not expect a single mono track to cause any problems. Could it be due to an integrated sound card (Gigabyte S Series motherboard) rather than a separate one?
Regards from Slovenia
Davslov

lol, thought you might say something like that.
Considering my 500MHz machine can handle 8 tracks, your computer spec should be able to handle loads of tracks,(I presume you mean 2.2GHz), however, the symptoms do sound like your computer is struggling to keep up. Possibly something to do with the way vista handles the USB mic and/or the onboard sound? As Vista is relatively new, the drivers may be far from optimised.

Something you could try is downloading Knoppix and run Audacity in that. Knoppix is a version (distribution) of Linux which runs directly off a CD without being installed onto your hard drive - you simply download Knoppix (from here http://www.knoppix.com/), burn it to a CD and boot from that CD (you may need to set your BIOS to boot from CD rather than from the Hard Drive). I'm not sure if Audacity is included by default, but if it's not, you can add it using "Synaptic". If Audacity works ok in Knoppix, then the problem is not with your hardware, but with Vistas support for your hardware.

This might seem to be a lot of trouble, but if you've not used Linux before, I think you will enjoy trying it out, and Knoppix is the easiest way to do this. If you get the same problem with Knoppix, then the problem is hardware, but if Knoppix fixes it, then you're looking at a Vista problem.

If you've not already done so, it may be worth having a look here:
http://audacityteam.org/wiki/index.php? ... ut_sources

My best guess is that the drivers for that mic don't work well under Vista.

From this page:
http://www.samsontech.com/products/prod ... rodID=1878

The C03U works seamlessly on any computer running Mac OS X or Windows XP, and with most DAW software programs without having to install any extra software or drivers.

They don't list Vista as being supported.

Hi
Reply from Samsontech about Vista compatibility: All Samson USB mics are fully Vista compatible. These mics are plug and play USB devices and require no drivers.
Knoppix solution sounds a little dramatic; but if I don't find an alternative, will certainly go there.
2.20 Ghz, of course!
Thanks again to all
Davslov

Actually, that Knoppix idea is a good one. I'll have to remember that for particularly tough cases.

One other thing to try is to use a different USB port (i.e. move to one in the back if you're currently plugged into the front, and vice versa). I once had a bad FireWire port that was giving me the occasional bad sample from a FireWire interface.

Just to conclude, you were absolutely right, alatham, it was just a sound driver issue; all updated now, crystal clear recording and playback. Many thanks for all suggestions
Best wishes, David