Scratchy sound on recordings

[ReMoss85]

This problem is very hit and miss, and I can't reproduce it at will. But about half of the time when I record a track, it has this horrible scratchy sound in it that almost completely overtakes the source audio. Some days it's worse than others, and I can't find any rhyme or reason to it. I always record with the same mic in the exact same way and I haven't changed anything when the problem does go away or come back. I've tried restarting Audacity, the computer, and closing all other programs, but nothing seems to have any affect. I've attached an example of the problem on a bass guitar track. Any ideas what it could be?

Thanks for your help!

[kozikowski]

Excellent. I don't mean the problem is excellent, I mean your sample was very clear.

Let me predict the past (pressing fingers to forehead). You're using a USB microphone, right? Are you running it through USB hub or other equipment? USB audio doesn't like that very much. USB microphones need a straight shot to the computer. One wire. No extension cables, either.

Unplug and replug the USB connection two or three times and try it again. Try plugging the USB into a different socket. Many computers have more than one. In particular, if you're using one of the computer front panel connectors, change to one in the back of the machine. If it's difficult to use and you have to hold a flashlight in your teeth, then that connector is much more likely to work.

Koz

[ReMoss85]

Actually I'm using an xlr mic into a phantom power adapter into a four channel mixer which is plugged into the line in on the back of the computer. Should I try plugging it into the mic input on the front of the computer? Maybe getting rid of the mixer altogether? I'll have to buy a 1/4 to 1/8 inch adapter for that... Oh the humanity!

[kozikowski]

No, no. Calm down. I need to think about this a minute. If you play the work back immediately after you record it, it's noisy then, right? Is there a way to plug headphones into the mixer and is the performance noisy there?

This is messy now. You messed up a perfectly wonderful technical explanation.

Koz

[ReMoss85]

Yes, it's noisy immediately, and there's no headphones out on the mixer. I'm assume it would be noisy in my headphone plugged into the computer if I used the "listen to this device" feature in the control panel, but I don't use it because of lag.

I plugged the mixer into the front mic input and so far it has been good (though again, it could start up at any moment) but now the problem is more hiss and more distortion (different from the scratchy problem). I have to turn the mixer fader almost down to zero for it not to distort and turn up the mic level on the computer, which causes extra hiss. I didn't have any of these problems with the line in!

[ReMoss85]

:Update:

It made the scratchy sound again. Boo.

[kozikowski]

The mixer out and the computer Microphone-In are fundamentally incompatible with each other. You really do need the Line-In on the back of the machine.

That's actually interesting. It's crackling even though you used the wrong connection on your sound card. That eliminates some of the causes of the problem. You can use the Mic-In on your computer with the existing microphone, but you need the right adapter cables. After the Phantom Power Insertion device, you need one of these...

http://kozco.com/tech/audacity/UnbalBalAdapter.jpg

I've never see that available commercially. I made that one so I could use this microphone...

http://www.bhphotovideo.com/bnh/control ... details&Q=

...with my sound card.

What are the part numbers of the phantom inserter and the mixer? Who made them? Either of them plug into the USB connection to get their power?

Koz

[ReMoss85]

I'm using a Rolls phantom power adapter PB23, and a Radio Shack four channel stereo sound mixer. There really isn't a model number I can find. And there's no USB anywhere the equation. It's all old school!

I've tried repeatedly to get it to crackle a second time and it won't do it in the mic input. I guess I'll plug it back into the line in anyway.

Also, I have Windows 7 and I can't get it to record internal audio. I've tried everything I've found in Google searches. When I go to control panel>sound>recording, there's no wave out, stereo mix, what u hear, etc. to be found. I have Aux, Microphone, Line In, and Digital Audio Interface, and I've tried every selection combination I can, selecting it there and in Audacity and I can't get it. Any ideas?

Thanks a lot for all your help by the way.

[kozikowski]

<<<Also, I have Windows 7 and I can't get it to record internal audio.>>>

Separate problem, but no, you can't. Neither can anybody else. Win7 left that tool out. Your choices are to use a USB sound device like the UCA202 we reviewed here...

http://forum.audacityteam.org/viewtopic.php?f=27&t=9477

...or use money-based software such as Total Recorder.

Koz

[ReMoss85]

:Another update:

I plugged back into Line In and turned on "listen to this device" and recorded until I got the scratchiness. It was not there while I recorded and listened live in my headphones, but was there on playback. If that tells you anything...