Quick n simple:

If you have a guitar playing with its signal split to two amps, and those amps are in separate rooms and being recorded with separate mics, is phase cancellation still a potential problem?

I should add: the reason I ask is because I read in one of these threads that having a signal split to two amps can produce phase problems, and I assumed this would apply to the two amps being in the same room.

I believe that yes. If the mics are placed on different places than the cab, the signal would get to them a different times. It won't necessary create a phase cancelation problem(depands on the mic placement), but there willl be a phase difference.

Um, maybe I'm not explaining myself properly.

The mics will be on the cabs, but each amp will be in a separate room - both being fed from the same guitar. The signal from the guitar will be split via a pedal. I'm terrible at explaining these things.

Okay...so the only thing I need to be concerned about here is the mics' distance from each cab? Amp types/lead length etc isn't a factor?

Thanks for your help, I appreciate it.

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themajormiller wrote:...

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I think the bigger issue is that some guitar amps will flip the polarity of the signal. Even this wouldn't be much of a problem since you could just flip the polarity of one of the mics.

As far as phase differences between the two amps, just make sure the mic distances are the same. Or don't. It all comes down to what sounds best to you. I guess that you are using two very different sounding amps. This is a sonically interesting way of creating a stereo sound from a mono source.

Like he said, many amps are switching polarity, but that won't be a problem.
If the speaker sizes are different between the two cabs, then it might create a problem two, cause then the two cabs are not moving the same way, and that might cause phase problems. But I think you should try that out anyway.

mic them up and listen to the mic on each amp individually. if they both sound like you'd like them to, then listen to both of them at the same time, panned stereo if you plan on doing that, and see how it sounds. if the two amps together sound thinner or wimpier than either amp by itself, try flipping the phase of one of the mics (assuming your mixer has this ability; if it doesn't, you'd need an XLR cable or adaptor that swaps pins 2 and 3 on one end). if flipping the phase of one mic makes it better, then you're fine. if it doesn't, or if you have time to fuck around anyways and dial things in a bunch, try moving whichever mic sounds less good on its own to a different location, either a subtle change or a major one, whatever makes it sound better than it did before. do that until the two amps combined sound good together.

the mp3 in my signature has a split signal running through two amps about 8' apart from each other in the same room, with a close mic on each amp. i'm a huge fan of multiple amps, and am even thinking about bringing a 3rd amp back into my setup, if only for shits and giggles.