Two mics on one cab....were do I start

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chadsxe

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I am in the process of gathering recording a metal band. We will be coming up on guitars in the next few days, and I figured I would ask a few question first so that I am better prepared. I have always recorded “blues type” music and have relied on one sticking on mic in front of the amp and moving it around until it sounds good. This method works fine for me when I have the option to re-track later down the road, but this time I don’t have that option. So I want to use a second mic for another option during post.

I am recording a Marshall DSL100 into a Marshall 1960 slant cab. I want to use either a Beta 57 or SM 57, and a KSM27. Is there any advice you can offer up as far general placements for the mics. The way I am thinking about going about is using one of the fifty sevens on the grill of on speaker, and sweeping it back and forth until I find something I like. Then I want to use the KSM27, but I don’t know were. Do I shove it as close as I can to the same position of the 57, in order to eliminate as much phase as I can, but still leaving me with two different guitar sounds? Or do I stick the 57 on speaker of the cab and the KSM27 on another? How much phase issues would I have with that placement. Or do I use the KSM27 in a radical place like the back of the cab or 7ft in front of it? As you can see I never have doubled miced a cab and all advice is going to be helpful.

Thanks
 
Double micing a guitar amp can be alot tougher than you think. There can be alot of phase issues depending on how you place the microphones so you want to set them up is basically the same spot. Why do you not have the option to use just one? Set up a few dummy mics and tell them you are mixing them to one channel. That if the sound is working. If its really benificial and not creating more problems then use multiple mics. If you are working with a 4x10 cab then youve got a few options for speakers. I would start with using the SM57 on the best sounding speaker. Try the middle, try the edge, try 2" from the edge pointed to the center, try in the center and angle it towards the edge, and all the variations in he middle. The other mics will be used to capture the sound that the 57 might not be grabbing. Might be best to put them in the same position on a different speaker as the 57 to avoid phase problems. But i would maybe put the mic on the opposite position of the 57. If you put the 57 on the outer edge put it more in the center. Check in mono for phasing problems though.

If its a 1960 cab then its probably closed on the back. And its a very thick cabinet. I dont think micing the back will work that well. When i mic these things it doesnt seem like much bass comes from the back. If you try it use the KSM27 and reverse the polarity. Check in mono.

DSL100 amps have worked pretty well for this stuff in the past. But they do have pretty harsh highs. I dont think they are toob but i cant remember for sure or not. Just try not to push them too hard.

Danny
 
Thanks for the reply

I have the option to use just one mic, but I would also like to diffrent sources to play around with in post.

The DSL100 is an all tube amp

I am thinking of putting a sm57 and a beta 57 on two diffent speakers but in the same spot. If I am correct this would elminate a lot of phase and yeild me the high/harsh sound of the SM57 and the more rounded sound of the Beta57.

Anyother suggestion would be great.

Thanks again.
 
Make the guitarist track it twice and use a different mic with each take. Just keep the stand and the clip in the same spot so when you switch mics, it'll be in the same spot. Plus, it'll sound like two guitarists instead of one and you can do some stereo seperation. Not that you wouldn't get the same result your way, but the same spot on a different speaker may not eliminate phase problems. If it were me, I'd make 'em track it twice.

Chris
 
Sorry for not being clearer, but they will be doubling and maybe even tripiling if needed. I am just trying to end up with as many options as I can i post.
 
I read this in a engineer's book....

"Phase issues start to dissapear if you follow this: Place the 2nd mic at least 3 times farther away than the 1st mic is from the sound source."

So I guess in your instance, if the 57 is 6 inches off the grill, it doesn't matter where the 2nd mic is as long as it is is 18 inches from the 1st mic.

I don't really know how true this is. I do know you have less phase issues with close miking vs. room/ambient due to the "air" involved. I don't typically experience any phase issues, and if I do, I have a handy little phase button that reverses it whenever I need.
 
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I saw a show once where one of the guitarists was playing thru 2 marshall stacks.It was quite loud onstage, but the FOH had a great sound as well. Backstage you could see the back one of the cabs had a small hole cut in it with a sm57 on a gooseneck sticking about 4" into the cab. Anybody ever heard of this?
 
GABritton said:
I read this in a engineer's book....

"Phase issues start to dissapear if you follow this: Place the 2nd mic at least 3 times farther away than the 1st mic is from the sound source."

So I guess in your instance, if the 57 is 6 inches off the grill, it doesn't matter where the mic is as long as it is is 18 inches from the other mic.

I don't really know how true this is. I do know you have less phase issues with close miking vs. room/ambient due to the "air" involved. I don't typically experience any phase issues, and if I do, I have a handy little phase button that reverses it whenever I need.
Click to expand...

This is called the three-to-one rule, and it works, in general. It is for micing two different sources, though. So it works close micing two different guitar amps, or two speakers in one cab. If you mic two speakers in the same cab, the mics should be the same distance away from the speakers. The sound from the source you are micing is so much louder than the bleed from the other source that the bleed doesn't interfere with the other mic signal when you play them both back. So you can record two singers in one room on two mics, and if you follow the 3-1 rule, on playback the phase problems will be (hopefully) minimal.

It won't work on phase issues resulting from a close mic and a far mic on the same source, though. In that case, you have to experiment with placement to get the least amount of comb filtering, and play with the phase switch like GABritton says.
 
Technically phase issues will always be a matter with two microphones. Phase issues will be there with two sources in general. There will be phase issues with Bass to the Guitar, vocals to guitar, and vocals to drums. Actually everything will have phase issues. Phasing is what creates a stereo feild. Infact you could say phasing has alot to do with the mix. Maybe thats why you are really getting the vocals to cut through the mix is because of phase problems cancelling out something else. Maybe not, but could be part of the physics.

Infact phase might be what is making that guitar sound bigger by making it wider stereo spread in some frequencies of the sound. But thats why its generally a good idea to not pan them exactly the same or put them in mono. Otherwise you get cancellation instead of spread.

The idea though is to to the cancellation to a point where its sounding good instead of canceling stuff out. The worst thing you can do is have it phasing at around 90 degrees. Cause then it might not make a big difference if you reverse polarity or not. Thats what it sucks.

Danny
 
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