Clipping problem

[garybullock]

Using 1.3.7 on windows XP, when recording, waveform is clipped at .5 instead of 1.0. This does not happen with the stable 1.2.6. I much prefer the noise removal in 1.3, but this clipping problem is driving me bananas. I use a Samson CO3U mic, to record books for Librivox. When I use a wireless headset mic, I don't get the clipping at .5. I really need some help here. I know I could record at a much lower level, then normalize, but that is certainly not an ideal solution.

[kozikowski]

This one's hard.

You could get those symptoms if the two Audacities were recording two different audio feeds. 1.2.6 is recording the microphone digital signal directly. The worst that configuration can do is be clear but too low, a common complaint with very good quality USB microphones.

However, if 1.3.7 is recording Mix-Out or some other pathway, then the signal becomes subject to extra pathways and obstructions. Each Audacity has its own input panel under Preferences.

I'm blue-skying now. In analog land, you get that when the microphone preamp (which typically has no controls) overloads ahead of the regular signal pathway. No matter what you do, the signal has severe clipping which is only better if the show gets quieter, or you attenuate the microphone feed. Shure Brothers makes attenuators that do this.

I'm betting the signal stays clipped if you reduce the Audacity input level, right? The signal and the clipping go down together, but it never gets better. So it's clipping ahead of Audacity.

On Windows machines, it's possible to record your own output by accident. This will give you an enormous uncontrolled gain boost and clip like crazy.

Are there any control panels for the microphone? Are they set up identically for both versions of Audacity? Did you check?

Koz

[steve]

There is a software volume control available for the Samson CO3U USB microphone which may resolve the issue - you can get it here: http://www.samsontech.com/products/prod ... rodID=1878

It also has a -10dB attenuation switch to prevent overload of the microphone when used for recording loud sound sources.

[garybullock]

The preferences were set identically in both Audacitys. I tried the Samson preamp software thinking it might solve the problem, but got no sound at all when I did, so uninstalled it. When I switch to -10dB on the C03U, the sound is WAY too low. I have a very simple setup, just recording voice reading a book, and I certainly am no sound expert. Call me a rank amateur. I don't understand why I had no problem with this under 1.2.6, and why I must have it now. You are right, the level and the clipping go down together. So what can I do about it? Is there an earlier version of 1.3.x that might not have this problem? I would gladly go back to using 1.2.6 if it only had the noise removal capability of 1.3.

[kozikowski]

<<<but got no sound at all when I did, so uninstalled it.>>>

That's a danger sign right there. You installed the microphone manufacturer's own software package on your known, good, working, stable machine and it failed. What's wrong with this picture?

<<<When I switch to -10dB on the C03U, the sound is WAY too low.>>>

But the distortion vanished? You need to pay surgically clear attention to everything that happens whether it's good or not. We take all the clues we can get.

<<<So what can I do about it?>>>

That's what's so darn much fun about your question. This can't be happening. The symptoms are most unusual.

This isn't an Audacity problem, by the way. If the distortion goes up and down with the Audacity input volume control then the sound is being damaged before Audacity gets it. The line here is that Audacity is a complete slave to the computer it's running on.

Although why one version and not the other......

Let's look at the rest of the machine. Do you have VOIP, Vonage, or Skype? What other sound programs do you have? Do you have other sound recording or music management programs?

I'll put significant chocolate on the Windows Sound Manager. It's different between the two Audacities. Did you dig around in the Windows Sound panel?

Windows Control Panel
http://audacityteam.org/wiki/index.php? ... trol_Panel

I don't blame you. I wouldn't go in there either if I didn't have to.

Koz

[kozikowski]

In Audacity 1.2.6, so you have Edit > Preferences > Audio > Do Not Modify.... checked?

Do you even have such a setting?

Koz