Mixing mono to stereo - keep getting noise on right channel!

[xxsuperjohn]

Hi all,

I have an old recording of my band on cassette which I have recorded from my music centre into my PC using the PC audio input. I know this method works because I have also recorded several vinyl LPs in stereo the same way, and they came out OK.

This cassette recording came off an old 4-track which recorded left and right channels separately, and the cassette has the actual music recording in mono on the left channel and some noise and other crud on the right channel.

The strange thing is that even though I have split the stereo track into left and right tracks, and deleted the right track, the resulting mono track still has a left-right slider, and if I slide this to the left I get a fairly clean recording (well it is off a 20 year-old tape so not that clean) but if I slide the slider to the right I get the same recording but with LOADS of white noise.

I slid the slider over to the left and exported as mp3. When I listen to this in another player (e.g. iTunes, Windows Media Plater) it sounds OK, the noise level is acceptably low. Of course I'm only getting audio out of the left speaker but it sounds OK. The right speaker is silent. I reimported this mp3 into Audacity with the intention to duplicate the left track in the right track and make it stereo (or 2-channel mono if you prefer). But no matter how I do this, when I slide the slider in the mono or stereo track to the right, or attempt to designate a duplicate of the track as a "right" track, the noise comes back in the right channel. It is driving me NUTS!

For example, I import the mp3, and split the track to left and right, then delete the right (silent) channel and duplicate the original left, and "make stereo track". But now the right channel has track plus white noise. The left is fine.

I saw another post here of a guy who had the exact same problem - a mono track which only goes noisy when you slide the left/right slider to the right. But in his case everyone piled in to tell him his microphone was s**t and the original issue never got solved.

I know my source file is OK because I can listen to the "left track only" mp3 in iTunes or my iPhone and the noise level is OK. But as soon as I bring the file back into Audacity and try to make a right channel, the white noise comes right back. Help!!!!!

Just to make sure I don't have some weird problem, I tried with both headphones and speakers, the problem is the same. Then I listened to some other good mp3, and both channels are fine. Then I imported a good mp3 into audacity, split the tracks, deleted the right, duplicated the left track and made a stereo track (i.e. the same process as I'm trying to do on my own file). It sounded fine.

With the problem file with the noisy right track, when Audacity plays past the end of the recording, the noise stops. So I am pretty certain that the noise is from the original source and not being added by my system in any way.

The weird thing is that when I copy the left track into the right track and make a stereo track, no matter how closely I zoom into the waveforms, they are clearly identical. But the right track always sounds noisy and the left track always sounds clean.

Oh yeah I'm on Windows 7 PC with Audacity 1.3.13 beta. It is a fresh install on a new PC and the first audio job I've done with this hardware or software. The project was actually recorded using Audacity 1.2 on my old XP PC, I don't know if this is relevant.

Any help appreciated, John.

[kozikowski]

music centre into my PC using the PC audio input.

Many people have lost recordings at this step. Exactly how did you connect the two and which audio input? Are you on a Laptop like this?

http://www.kozco.com/tech/audacity/pix/ ... pSound.jpg

But in his case everyone piled in to tell him his microphone was s**t and the original issue never got solved.

Well, maybe not that, but the microphone was mono and special considerations must be made to record one of those.

When you're at the step where you delete the clearly noisy right track, use the drop-down track menu to convert the track remaining to mono. Then export and all traces of the right-channel noise should be gone. Don't touch the volume or fader controls for the track. Those are magic and do things behind the scenes.

Once you have a mono track, duplicate it and using the same drop-downs to Make Stereo Track if you want to. It's wasteful and not need in most circumstances, but I do it because it gives me a warm, fuzzy feeling.

Koz

[steve]

The strange thing is that even though I have split the stereo track into left and right tracks, and deleted the right track, the resulting mono track still has a left-right slider, and if I slide this to the left I get a fairly clean recording (well it is off a 20 year-old tape so not that clean) but if I slide the slider to the right I get the same recording but with LOADS of white noise.

That is mysterious. There's no obvious reasons in Audacity why that should (or could) happen. We may need to look deeper into this issue.

This cassette recording came off an old 4-track which recorded left and right channels separately, and the cassette has the actual music recording in mono on the left channel and some noise and other crud on the right channel.

Assuming that you have Audacity 1.3.13 (Unicode), the way to split the stereo track is as follows:
1) Click on the track name.
2) From the drop down menu, select "Split Stereo to Mono" (NOT "Split Stereo Track"). This option is only available in recent versions of 1.3.x, so if that option is missing then you should upgrade to Audacity 1.3.13 which you can get here: http://audacityteam.org/download/
3) Click on the [X] in the top left corner of the crud track.

When you export, the resulting file will be mono and will play through both speakers.

If you specifically require a 2 channel track (not normally required unless you intend to add stereo effects such as panning or stereo reverb), then to create a 2 channel track (strictly speaking this will still be mono as both tracks are identical):
4) Duplicate the track (Edit menu or Ctrl+D)
5) Click on the name of the upper track and select "Make Stereo Track" from the drop down menu.

When you export, the resulting file will have two audio channels and will play through both speakers. If it is in an uncompressed format such as WAV or AIFF the file size will be double the size of a single channel mono file but will sound identical. If exported in a compressed audio format such as MP3, either the file size will be larger or the sound quality worse than a single channel mono track (depending on the MP3 options that you use).