Phasing Problems?

[thesound]

I think I am grasping the meaning of Phasing Problems. So I ask, are phasing problems a problem that only live performers/recorders will suffer from? Ie: A drummer micing up a kit or a guitarist using more than one mic or using more than one take or is this a problem that anyone can suffer from. Say, a computer based muscian.

It could just be that this is something I have totally overlooked.. How would someone go about finding out if they have phasing problems and how would they go about setting them right.

If you could maybe have a few examples of phasing problems that I have not mentioned that would be helpful. The common one seems to be the micing of a drumkit which does not really affect me.

Thanks

Edited May 23, 2010 by thesound

[john]

hey

Good questions...

Out of phase signal issues occur whenever one source signal is split into two parts, each part taking a different signal path and then those signals are re-combined. this can happen with recordings with more than one microphone, a source recorded with one microphone and DI, or one source split two go down two different effects chains.

The issue is most noticeable with very small delays differences between the timing of those signals. In the case of two mics being used to record the same source the difference in distance between the microphones and the source are the primary culprits and it's not unknown for engineers recording using two mics to measure the distance between the source and each mic.

For a basic primer try our Phase Relationships article.

Generally computers work so fast that discrepancies timing wise are not too bad an issue, however if you start introducing multiple effects chains that result unintended delay on one signal path, you will get some coloration of the sound.

On detecting it, you use your ears... so good amplifier and speakers and a good set of cans is important. This issue is more.. when phase is noticeable and unwanted. We can't always eliminate phase issues, most not coloring the sound sufficiently to be too obvious so they don't get addressed. and that is exactly what you are looking for, unintentional coloration of the sound.

I hope this helps

Cheers

John

[Retrosaurus Rex]

One thing John overlooked, that might be a significant problem for you as a computer based musician, esp if you're doing something along the lines of dance/ club/ hip-hop... disappearing bass. Bass frequencies tend to be more susceptible to phase issues, not just in unwanted coloration, but also in a lack of power. This can happen if you have a kick drum, snare drum, bass, & phat synth all going on at the same time. In this case it's probably time to use EQ to carve out specific sonic spaces for each element.

Check out some articles...

http://recording.songstuff.com/article/equalization_eq/

http://recording.songstuff.com/article/eq_frequencies/

[BriSmi75]

just check the mics against each other on whatever you're recording, flip the phase and see if the low end goes away or comes back. I.E. if you're recording an acoustic with 2 mics, set up one and flip the phase on the other one and see what happens. Also, zoom in on the waveforms and check the image