Acoustic guitar w 2 mics...

jmpatrick wrote on 2/23/2005, 7:03 AM
I've been experimenting with the mixing of a track that includes acoustic guitar. The acoustic was recorded with 2 mics on seperate tracks: 1 was aimed in front at the point that the neck meets the body, and the second was placed about 2 feet over the players shoulder, pointing down. At mixdown, I panned the 2 tracks hard left and right I'm very pleased with the lush stereo results, but I'm concerned about phase issues and mono compatibility. If I reverse the phase of one of the tracks, I lose a lot of the spacious stereo effect. When I check the mix in mono, the acoustic sounds a bit fuller with one track reversed...but not a big difference. I also have the same sort of issue with hammond organ recorded through a leslie speaker. I miced the the horn rotor on to one track, and the bass rotor on a second track. At mixdown, it sounds great when the 2 tracks are panned hard left and right. Again, I'm concerned about potential phase cancellation issues.

Any thoughts?

jp

Comments

PipelineAudio wrote on 2/23/2005, 7:59 AM
just for kicks, zoom WAY in and align the peaks on the two tracks, flip one if you have to, and then see what it comes out like.

Also you can make a parallel send, by sending both or one of the tracks to an aux buss, then throwing the track eq on that buss,filter out the highs like from 500hz or so on up, pan it center, then slowly mixit into the other faders ( maybe with the lows below like 400 or 500hz rolled off on the main tracks)
cosmo wrote on 2/24/2005, 8:57 PM
yeah dude, I like the line of thinking. I've long been a fan of mixing mics on acoustics. Stereo micing on electrics sounded so good I figured why not with the acoustic. I like to place one over the neck sometimes also. If you have a clean guitarist, it actually sounds really nice...very 'real'. I think some of the finger scratching/sweeping/squeaking on the strings is lost with standard micing techniques, and in reality we pick up on that. I also liek to mic a bassy spot on the body...but that requires much trial and error.
Rednroll wrote on 2/24/2005, 9:33 PM
This is a good micing technique. On Acoustic guitar I often place one mic close pointed at the bridge and another 3-6 feet back to get a fuller sound. Here's what you need to do, to fix your phase issues you're describing. You need to delay the sound of the mic closest to the sound source. Sound travels at 1128 ft per second. What this means is that there is roughly a 1 mS delay per foot. So in your case, the mic aimed at the point where the neck meets the body (ie bridge) is your closest mic. You need to delay that mic so that it time aligns to the mic placed over the shoulder. So I'm imagining they're roughly spaced 2 feet apart, so put a delay on the brige mic of roughly 2 mS as a starting point. You can also zoom in closely and then time align by moving the one track by matching up their zero crossing points as previously mentioned. You'll find the amount you move that track will match up with my 1 mS per foot rule. Or you can do it by feel and use a delay on the track. What you do is take an estimate for the initial delay setting of the 1mS per foot that I mentioned and put that on the mic closest to the sound source, then reverse the phase of that track. Now fine tune the delay, so the sound eventually sounds as thin as possible when listening to both tracks set at the same volume and panned center. Once you've reached that point, now invert the phase back to normal on that track, and wallah a rich direct sound mix of both mics. This is also a good technique if you have the time, when putting multiple mics on a live drum set. The out of phase flip trick I described gives you the easiest way to tell they're time alligned, because it's easy to hear the maximum phase cancellation point when fine tuning the delay setting. So since they're canceling out the most and sound thin when they're 180 degrees out of phase with each other, then they must be not phase cancelling when you put that phase switch back to normal.

I only wish I made music for a living so I would know more about that type of work and multiple micing techniques......oh well, I try.

Red