How do I read x-y graph?

GoldWave general discussions and community help
Post Reply
Dumbolino
Posts: 12
Joined: Wed Jun 28, 2006 9:54 pm
Location: Berlin, Germany

How do I read x-y graph?

Post by Dumbolino »

Hello,
I have to edit some soundfiles for a video production and I would like to check visually the mono compatibility of the files. Is it possible to use the x-y graph display for this purpose and if yes, how do I read it. And if no, what's the use of this display, what can I read from it and why can I swap x and y in the options?
Thanks in advance

Dumbolino

(And yes, I know the best mono compatibility check is my ears! :D )
Blandine Catastrophe
Posts: 253
Joined: Sun Jul 24, 2005 3:25 pm

Post by Blandine Catastrophe »

Assuming that you have not swapped X/Y:

The vertical direction indicates the modulation of the right track, and the horizontal direction the left track.
A monaural signal equal in both tracks will show a diagonal Left-Bottom to Right-Top
If you see a diagonal Left-Top to Right-Bottom, that means that the signal is phase inverted, and if you join both tracks, that will cancel this signal. It is good to cancel some reverb, which can be a disturbance in mono, but not the music or talk.

A "normal" signal may show you some random distribution of the line, with a trend to get rather a direction Left-Bottom to Right-Top.

If you have a sound synchronized with a sample precision in both tracks at equal level, and a reverb applied on it, you have usually an elliptical shape on the diagonal.

Spectrogram: You can have also some indications that you have a fake stereo in your audio material. It doesn't work always but if you have that it is surely a fake stereo: in the Spectrogram, when you see alternate dark and clear stripes, a dark stripe displayed for a track will show a clear stripe at the same frequency on the other track. You can mix both tracks from stereo to mono if it is was properly done, but if there is an additional reverb in stereo instead of phase inverted, this reverb can be an annoyance and a cause of incompatibility. You can know only by listening to the result.

If you convert from stereo to mono a sound from a video, and there is a movement of the sources and/or of the microphones, it can cause some unwanted spectral effects because of these movements. It is better in this case to use only one channel. If you send a stereo signal and people receive in mono, they have not so good a speaker system, so it is not a real problem if you don't notice something huge by monitoring.
Gloup? :-°
Dumbolino
Posts: 12
Joined: Wed Jun 28, 2006 9:54 pm
Location: Berlin, Germany

Post by Dumbolino »

Hey, thank you very much! The spectrogram info and the general info are also very helpful!

Greetings
Dumbolino :D
GoldWave Inc.
Site Admin
Posts: 4372
Joined: Wed Mar 10, 2004 6:43 pm
Location: St. John's, NL
Contact:

Re: How do I read x-y graph?

Post by GoldWave Inc. »

The Effect | Stereo | Channel Mixer effect can be used to mix the left and right channels to mono using several different methods. The "Cancel vocals" preset subtracts the two channels so you can hear differences between them. A true mono file would give pure silence.

Chris
Post Reply