recording a mic'd amp

[ggmmss]

i have been using guitar rig 2 and other various digital simulators. i have really been wanting to record a real tube amp specifically mesa boogie. i have never really recorded a micd amp and kinda nervous about spending 1000.00 plus on the hope i can get a good sound with it. i am trying to decide between a dual rec tremoverb which they say sounds good at lower levels or the safer route the recto recording pre which a lot of people complain doesnt have any low end. the room i have set up for my studio has hardwood floors and is basically a spare bedroom with no sound treatment at all. i will be using a shure sm-57 if i go the tremoverb route. any tips on room treatment or basic amp micing would be greatly appreciated.

[daeron80]

First of all, the sound comes from the fingers. If you sound good with plug-ins, you'll sound good through an amp, and vice versa. One of the best guitarists and producers I know once got frustrated with me for my meticulous approach to miking his amp, and said, "Let me tell you my secret microphone technique. If you want to record something, get _a_ mic and POINT IT AT IT." In some ways, that was brilliant advice. It is possible to get so consumed with the details that you miss the big picture. But you will encounter problems, and it's helpful to have some idea how to solve them.

The placement of the amp in the room will have as big an effect on the tone as the placement of the mic on the amp has. Unfortunately, it's not possible to tell exactly what a mic will hear at amp level by listening from a few feet away, and you sure don't want to put your ear down there while someone plays. But it's a way start the process, at least. Generally, if you need more low end, move the amp closer to a corner (the recto lacks low end because it can't benefit from room modes); if it's muddy, usually you'll want to move it further away from walls (this only applies to rooms where the longest dimension is less than about 30 feet and when the amp is within a couple feet of one or more walls).

Whether it's muddy or thin, try to identify the problematic frequency range, calculate the wavelength, identify the responsible mode, and move the amp accordingly. If you haven't studied acoustics yet, just keep moving the amp around until it seems to sound good. In a room with an 8' ceiling, it sometimes helps to get the amp off the floor onto a chair, stool, or table. It depends on the song, too. You may need to place the amp differently for different songs, depending on what frequencies need reinforcement and which frquencies can't tolerate it. For instance, a song in the key of D may sound bad with the amp on the floor because the 8' ceiling is strongly reinforcing 141.3 Hz at the floor level, which is a quartertone below the 146.8 Hz frequency of the low D on the guitar; that can cause ugly beating. Getting the amp about 2' above the floor would solve that, while placing it about 4' up would not. You can do the math if you like, or you can just start trying different places until it sounds good.

Each speaker has its own unique sonic fingerprint, which is one reason plug-ins will never completely replace the real thing. To place the mic, turn the amp on and turn it up to tracking volume, then turn down the volume(s) on the guitar itself. Get a little piece of tape, or something small and a little sticky, to mark the grill with. Put your ear down near the grill and slowly move it around, listening critically to the hiss pattern. The different balances of bright and dark are easy to identify. With practice you can learn to identify the overall shapes and phases of the hiss. You'll learn what "good hiss" sounds like. Where the hiss sounds sweet, the mic will sound sweet. Where the hiss sounds twisted, the mic will hear twisted guitar tone. Where the hiss sounds focused, the mic will pick up a focused tone. Mark your chosen spot with the tape, and place the mic there, within an inch or two of the grill.

Axis should be considered according to the part the guitar is playing. If it's a lead sound, you probably want the mic pointed straight, 90 degrees to the grill. If it's a rhythm part, it may need to be angled a little, about 10-15 degrees off-axis in one or both dimensions. Whether that angle is toward or away from the center of the cone depends on the amp, the speaker, room, and everything else. It's strictly trial and error. With practice, you'll develop intuition for it.

Room treatment is a complicated subject. Bare walls can be good for close miking an amp, although longer reverberation tends to exacerbate colorations. Hardwood floors tend to make for a warmer tone and a pleasant decay.

For monitoring and mixing, you want a lot more absorbtion and diffusion. That's one reason control rooms look and sound very different from tracking rooms. When you have to do both in one, it's a compromise on both ends. There's no way anyone can tell you very much without an on-site evaluation. If flutter echos are a problem at the mix position, a throw rug on the floor under your chair will help the floor to ceiling ones, and hanging a flannel shirt or something on each wall immediately to your right and left will damp those a little. I have an 8'X6' rug hanging from the ceiling just behind my speakers in my home studio, at a distance calculated to absorb a build up of axial and tangential modes in a particular frequency range, giving me something vaguely like a dead-end-live-end design. It looks kinda kooky, but it works.

But what helps one person's room may make yours worse. Learn as much as you can about small room acoustics, and always let your ears be your guide.

Sapere aude,