analyzing stereo and mono tracks

Help for Audacity on macOS.
Forum rules
ImageThis forum is for Audacity on macOS 10.4 and later.
Please state which version of macOS you are using,
and the exact three-section version number of Audacity from "Audacity menu > About Audacity".


Audacity 1.2.x and 1.3.x are obsolete and no longer supported. If you still have those versions, please upgrade at https://www.audacityteam.org/download/.
The old forums for those versions are now closed, but you can still read the archives of the 1.2.x and 1.3.x forums.
gpz
Posts: 52
Joined: Thu Nov 28, 2013 9:59 pm
Operating System: Please select

analyzing stereo and mono tracks

Post by gpz » Thu Nov 28, 2013 10:30 pm

I am using OSX 10.9 and want to know if i can analyze a track in audacity to check stereo vs. mono and if so how do i do this ? thank you

Gale Andrews
Quality Assurance
Posts: 41761
Joined: Fri Jul 27, 2007 12:02 am
Operating System: Windows 10

Re: analyzing stereo and mono tracks

Post by Gale Andrews » Thu Nov 28, 2013 11:06 pm

If the track says mono on the left it is mono and there is no debate.

If the track says stereo on the left and you want exact information on how much the two channels are alike ("correlated"), try the "rjh-stereo-tool" from http://forum.audacityteam.org/viewtopic ... 89#p216689 . It is a Nyquist plug-in. Please see here for how to install Nyquist plug-ins: http://wiki.audacityteam.org/wiki/Downl ... ns#install .

Choose the "2-D Stereo Toolkit" from the Effect Menu then the "Analyze" option.

If you prefer a simpler test, click in the name of the stereo track and choose "Split Stereo to Mono". Click in one of the Track Control Panels where it says "Mono" then choose Effect > Invert from the menu at the top of the screen. This turns the waveform of that track upside down.

Now press Play. If you get silence (no green dancing bars in Meter Toolbar), that means the stereo track that you split was "dual mono", that is the same content is in the left and right channels. When you make both channels into mono tracks, invert one of them and the content of both tracks is the same, then the inverted track will exactly cancel out the other track, resulting in silence.


Gale
________________________________________FOR INSTANT HELP: (Click on Link below)
* * * * * Tips * * * * * Tutorials * * * * * Quick Start Guide * * * * * Audacity Manual

gpz
Posts: 52
Joined: Thu Nov 28, 2013 9:59 pm
Operating System: Please select

Re: analyzing stereo and mono tracks

Post by gpz » Fri Nov 29, 2013 2:17 am

thanks Gale i will check this out. I had a rude awakening as i just finished an album sent it off the mastering guy at the record label and he called me much to my shock said the tracks were mono. I could believe it because they are 2 channels showing and it says stereo even when i check in audacity. He said it doesn't matter a track can have 2 channels and still be mono because they are both the same. Something went wrong on mix down.

gpz
Posts: 52
Joined: Thu Nov 28, 2013 9:59 pm
Operating System: Please select

Re: analyzing stereo and mono tracks

Post by gpz » Fri Nov 29, 2013 2:20 am

i downloaded that tool but my Mac says there is no application to open it. So i assume audacity won't do this right ?

gpz
Posts: 52
Joined: Thu Nov 28, 2013 9:59 pm
Operating System: Please select

Re: analyzing stereo and mono tracks

Post by gpz » Fri Nov 29, 2013 2:21 am

sorry i see you gave me a simpler test in audacity i will try it.

gpz
Posts: 52
Joined: Thu Nov 28, 2013 9:59 pm
Operating System: Please select

Re: analyzing stereo and mono tracks

Post by gpz » Fri Nov 29, 2013 2:36 am

so i tried that on the track that mastering guy said was mono and sure enough silence thank you. I tried the same thing on a stereo track i know is stereo and the track deleted is that correct ? So my conclusion is stereo and seperation is tricky business and 2 channels does not tell the story. I have done 45 albums in my career and just started recording at home so never had to learn anything the engineer did everything for me :)

Gale Andrews
Quality Assurance
Posts: 41761
Joined: Fri Jul 27, 2007 12:02 am
Operating System: Windows 10

Re: analyzing stereo and mono tracks

Post by Gale Andrews » Fri Nov 29, 2013 3:12 pm

gpz wrote:i downloaded that tool but my Mac says there is no application to open it. So i assume audacity won't do this right ?
As per the installation instructions, all you have to do is copy the ny file into the Audacity Plug-ins folder and restart Audacity.
gpz wrote:so i tried that on the track that mastering guy said was mono and sure enough silence thank you. I tried the same thing on a stereo track i know is stereo and the track deleted is that correct
No you should have had quieter stereo playback.


Gale
________________________________________FOR INSTANT HELP: (Click on Link below)
* * * * * Tips * * * * * Tutorials * * * * * Quick Start Guide * * * * * Audacity Manual

gpz
Posts: 52
Joined: Thu Nov 28, 2013 9:59 pm
Operating System: Please select

Re: analyzing stereo and mono tracks

Post by gpz » Fri Nov 29, 2013 4:19 pm

thanks Gale yes i re-tried it and i did have a quieter track stereo. Sounds like i don't need the plug in or does that do more than what i am doing on audacity now ? I have a dis-related question maybe you can answer. I had to re-burn these tracks to CD from MP3 files because original Wav files weren't available. My question is when when you push "create audio CD" and burn a CD it decompresses the file back from MP3 to CD red book standards automatically ?

gpz
Posts: 52
Joined: Thu Nov 28, 2013 9:59 pm
Operating System: Please select

Re: analyzing stereo and mono tracks

Post by gpz » Fri Nov 29, 2013 4:28 pm

I downloaded the plug in you suggested and it is on my desktop how so i put it in audacity i don't see any instructions ? By the way your help is fantastic thank you ! My website is glennzottola.com

kozikowski
Forum Staff
Posts: 68921
Joined: Thu Aug 02, 2007 5:57 pm
Operating System: macOS 10.13 High Sierra

Re: analyzing stereo and mono tracks

Post by kozikowski » Fri Nov 29, 2013 4:28 pm

There is another way to do this that is a lot faster, but not quite as accurate. Drag-select a tiny bit of the mix-down in the middle of the show and magnify it Command-E. Do that several times until you can see the individual ups and downs of the blue waves. It's very highly unlikely the the waves will be exactly identical in a multi-instrument stereo mixdown. The illustration is of two-track mono (what you apparently have) and then real stereo.

Command-F to zoom out full and Command-3 to zoom out a little bit.

You can fake this out. If you happened to zoom into a portion where the lead singer is singing in the left-right middle of the show with no accompaniment, then the waves will appear identical, so this isn't foolproof, but it's a lot faster.

How did you record the show? Does your Mac have a stereo Line-In like this?

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

Koz
Attachments
Screen Shot 2013-11-29 at 8.04.16 AM.png
TWO-TRACK MONO
Screen Shot 2013-11-29 at 8.04.16 AM.png (51.46 KiB) Viewed 4277 times
Screen Shot 2013-11-29 at 8.12.06 AM.png
REAL STEREO
Screen Shot 2013-11-29 at 8.12.06 AM.png (35.75 KiB) Viewed 4277 times

Post Reply