Visual analysis

[Yiannis]

could someone explain the vectorscope and the spectragram?
What can you see on a vectorscope that you can't on a phase correlation meter and on a spectragram that you can't see on a FFT analyzer.

Thank you!

[jazzius II]

A vectorscope is really just a more detailed version of a phase correlation meter. You need to learn to read it (vectorscope), whereas a PCM shows you a more general in/out phase situation. A vectorscope can show you things like DC offset (which a PCM can't).

An FFT shows you a detailed (unless it's a Klark Teknic ) view of the frequencies that are present right now, whereas a spectragram is less detailed but shows you what has been happening frequency wise over the last few minutes.

[Yiannis]

Jazzius II my main problem is that I don't understand the vectorscope.
could you explain it or is there any articles that you could mention?

thank you

[Yannick]

It's just pretty to look at, and when the musicians' intonation is good and the music not complex you get really some nice flowery figures

Basically, what's in the upper quadrant is between the loudspeakers, the 3 and 9 o'clock quadrants means the audio is uncorrelated, so falling out of the speakers.

If your blob is too flat : no good, if it's to narrow : monoisch.

Also, in a hectic classical multimic production you can pan spot mics exactly on the correct position by comparing with the main mic. That is THE advantage over a PCM, you can actually see where an individual musician is sitting (if he plays alone of course). Eg blumlein stereo has a rather narrow recording angle (90 deg) and if anything is just outside or on the edge you can get into trouble, on a vectorscope you just ask to play three notes and you can immediatly see the problem.
Handy in bad monitoring or headphone environments ...