compensating for too much input gain after the fact

[Robert Dodier]

Hi,

I recorded a band from an output on the mixing board to the mic input of my laptop. I now know that's not a good idea, because the mic input expects a weaker signal and the line out is too strong. The input level meter was pushing the top (right) end of the meter window and the recorded track sounded very harsh. I reduced the input volume and that did reduce the volume, but to the input meter was still pegging the top limit and the waveform display showed the same general picture as before (almost solid), but with a smaller amplitude. The sound engineer reduced the line out volume, and that helped somewhat, but the harsh sound was still there.

So, that's all pretty messed up. Is there anything I can do to process the recording to make it sound better? Any effect or other processing that can make it clearer and less harsh would be great; I don't need to make it perfect, just clear it up somewhat. If it helps, I can post waveforms or spectra or a snippet of the track itself, if it would help.

I'll try to get a different sound card for my laptop which has a separate line-in input, so I don't have to use the mic input again. (Any recommendations for such a sound card? I have a Toshiba laptop with Windows Vista.) But in the meantime, I'd like to try to salvage the recording I have.

Thanks a lot for your help, I appreciate it very much. Many thanks to the Audacity team for this great program.

Robert Dodier

[kozikowski]

You're clear what you did wrong, so that's half the battle. We've been recommending the UCA202 USB connected sound card for High Level Stereo Input (and output).

http://www.behringer.com/EN/Products/UCA202.aspx

There is a tool in Audacity 1.3.12 called Effect > Clip Fix. It may help a little. Reduce the level of the show with Effect > Amplify, -3dB and then apply Clip Fix.

It's not going to work, but it's worth a shot. By the time most people notice clipping damage, it's too late. Clipping or overload damage is, for the most part, permanent and fatal.

We tell people if it's a choice between too high and too low, go for too low. You have a fighting chance to recover from that.

The show in the file is also mono, by the way. Mic-In only records "left." On some machines, it appears to be stereo, but if you pay attention to the bouncing green playback meters, they're identical.

Koz

[steve]

There is a tool in Audacity 1.3.12 called Effect > Clip Fix. It may help a little. Reduce the level of the show with Effect > Amplify, -3dB and then apply Clip Fix.

For ClipFix you may need to allow a bit more overhead than 3 dB. Assuming that Audacity is working in 32 bit (default) I'd suggest reducing the gain by -10 dB before applying ClipFix. The "restored" peaks may go up to 8dB or more above the clipped level. If they go higher than that then it's not going to sound good whatever you do.

We've been recommending the UCA202 USB connected sound card for High Level Stereo Input (and output).

I've got a UCA 202 and it's fantastic for the price, but it does have its limitations - it can't handle true "line level" without distorting. This is not a problem when recording from a mixing desk as long as you take care not to let the signal to the UCA 202 get too "hot". Keep the recording level in the "green" and the UCA 202 will do a great job (and all for $30).

[whomper]

"true" line level ?? What is that ??

you mean the +4dBu professional "line" level
or
the -10dBv consumer "line" level ??

I say it works fine for consumer line levels
and
you need a pro interface
if you want to use pro line levels.

[Robert Dodier]

Hey everybody, I just wanted to follow up to report that the UCA 202 works well for my purposes. I tried the same basic set up as before, recording from a club's mixing board to my computer. This time, I got the input from the UCA 202. It is not the most brilliant recording in the world, but it is 100 times better than it was before! Thanks for the hint.

[bgravato]

Hey everybody, I just wanted to follow up to report that the UCA 202 works well for my purposes. I tried the same basic set up as before, recording from a club's mixing board to my computer. This time, I got the input from the UCA 202. It is not the most brilliant recording in the world, but it is 100 times better than it was before! Thanks for the hint.

Glad to hear. Thanks for the feedback!