phase issues

[kmaaj]

context is stereo mic'ing solo classical guitar, and I was getting a real nasty thin stratty tone today. It did not matter what config, XY or spaced, or where the mics were, the phasing was there and would go away when I muted one channel or the other. So I can safely rule out mic placement, right? Did the exact same thing in Audacity and Ableton. I got rid of the problem in Reaper by switching to 2 mono channels, panning hard left and right, and inverting the phase on one channel.

Is it normal to need to invert the phase on one channel when stereo recording one source?

Is there anything in the chain aside from mic placement that can cause phase problems before the signal hits the DAW?

As it sits right now, I have to use 2 mono channels because I do not see any way to invert the phase on one side on a single stereo channel. Am I missing something?

[Nip]

I would say - mic placement, yes.

That comes with using multiple mics. You really have to make test recordings to be sure - sometimes it's just centimeters that are needed.

But since it's not always 180 degree phase shift button does not fix everything. You could still get boxy sound.

You could try processors like Waves S1 which do many clever things.

I use for all kinds of narrowing of stereo field which involves cancelling effects due to phase.

[mabian]

Try Variety of Sound PreFix: it can take two mono channels and help you align them non destructlvely very quickly:

http://varietyofsound.wordpress.com/vst-effects/

http://varietyofsound.wordpress.com/...ignments-done/

Hope that helps,
Mario

[Moonwrist]

Originally Posted by kmaaj

Is there anything in the chain aside from mic placement that can cause phase problems before the signal hits the DAW?

Yes.
A microphone cable that is wired incorrectly.
A normal microphone cable has three wires: 1 ground, 2 phase(+) and 3 opposite phase(-). If in either end of cable phase an opposite phase are changed to wrong pins you have signal whit inverted phase.
Also some pre-amps have a button to invert phase. Maybe you have accidentally pushed other channel inverted.

[Grag38]

Whenever an musicien is using an DI and a Mic for his instrument implies to check the phase of the 2 signalsl that comes into the desk mixer or a daw.

The phase is due of an delay between the 2 signalsl that do not come 'at the same time'.

It's esay to check :

Record an small interval of the both signal and zoom to the result.

You can then applies an delay to 're align' one signal to the other. It s a better way of doing it comparing of inverting the phase .

[tspring]

If mics are exactly equidistant from the sound source, there should be no need to invert phase of one channel (unless cable or mic itself are wired wrong).

Did I understand correctly that moving the microphones relative to the sound source had no effect on "the out of phase sound" that you were hearing? If so, something very odd is going on. Even if the mic cable for one of the mics had been wired with phase reversed, there should be some placement of the mics relative to the sound source where phase cancellation is minimized, and another where it is maximized. So if you pan both channels to center and monitor signal through headphones while moving the mics relative to each other and sound source, you should be able to find a sweet spot where phasing is minimized even if you have a hardware problem that is shifting phase of one signal. Also note: The closer the mics are to the sound source, the greater the effect of differences in distance of each mic to sound source, so moving back at least 18 inches from the guitar will make it easier to get spacing 'correct'.

T

[kmaaj]

Guys, thanks, but I feel stupid. It turned to be a faulty contact between the headphone jack and the headphone adapter. The problem went away when I later plugged the headphones directly into the laptop. F/P, and first order of business is getting a decent set of headphones that have a 1/4" jack.