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recorded traks not centered at 0 on Waveform

Posted: Tue Jan 27, 2009 10:26 am
by davidmcc3
I use 3 differnt PCs to record using Audacity. I use 1.2.4 - the same download file installed on all of them, and they're all running XP SP2

On one of them, the recoding is not centered at the 0(zero) point in the Waveform display ... and the left & right channels are off-center by different amounts.

What is the problem? Can it be fixed? Does it actually matter?

I've attached a screen print to illustrate.

Re: recorded traks not centered at 0 on Waveform

Posted: Tue Jan 27, 2009 12:05 pm
by kozikowski
The odd one has battery voltage mixed in with the sound. I have a USB microphone amplifier that does that.

Effect > Normalize > Remove DC Offset.

You'll have to do that after every recording on that machine. Whatever device is converting analog audio signals to digital is broken. I have also received internet audio productions with that problem.

DC or battery voltage mixed in with the sound makes clean editing almost impossible. If you find a very quiet segment in a recording and insert a one second silence from the sound generator, the silent segment will pop or snap at each end.

Koz

Re: recorded traks not centered at 0 on Waveform

Posted: Tue Jan 27, 2009 1:03 pm
by davidmcc3
Thanks for the reply ... does that mean the sound card/chip in the PC is faulty?

Regards

David

Re: recorded traks not centered at 0 on Waveform

Posted: Tue Jan 27, 2009 1:04 pm
by davidmcc3
Sorry ... forgot to mention all recordings are streamed from the Internet

Re: recorded traks not centered at 0 on Waveform

Posted: Tue Jan 27, 2009 3:17 pm
by kozikowski
Left out a step. In Audacity 1.2, you have to Edit > Selet > All first. In 1.3, you don't have to do that.

This could answer a question I've had about this for a while. I've never done the research. Does it do that on a good and a bad computer if you download the exact same show file?

Download the six second piano2.wav file from here...

http://www.kozco.com/tech/soundtests.html

...and see if that's different between the two computers.

Koz

Re: recorded traks not centered at 0 on Waveform

Posted: Tue Jan 27, 2009 9:22 pm
by davidmcc3
Hi Kaz

It's not the files for sure. I have tried the same file on all three ... its only the old Dell which is misbehaving ... and on every download.

Can't afford to pension it off ... but could get a new sound card it that is the problem

David