When you track a guitar, you have two options, amp or direct. I have been know to do both, depending on the situation. Today I want to talk about the amp option. Specifically single mic vs multi miking techniques.
Miking with a single mic is probably the easiest and most straight forward way to go. Just put a mic in front of the speaker, right? Well, not really. There are many variables to think about. You have the amp, the mic, the distance the mic is from the speaker, the position of the mic, etc.
Of course, things always go better when the source is good, so having said that, a nice amp is a must. It doesn't have to be a Marshall half stack or a Fender twin, just a good sounding amp. Cheap, practice style amps won't cut it in the studio environment. I'm not talking low wattage, small amps - there are many companies that make smaller amps like Marshall and Blackstar that are excellent.
Then comes the microphone. Most engineers have a "go to" favorite for guitars. Some like the good 'ol SM57. Some like the Sennheiser 906. I lean mostly on either an AKG 414 or an Audio Technica 4050.
The position and distance also matter. If you want a tight sound, move your mic in close. A more roomy sound? Pull it back to get more natural ambience. Also, the position on the speaker itself matters. If you are dead center, it's going to be a brighter sound. More on the outside edge and you'll get a more bassy sound. I like to be about 2 inches off center, personally.
The volume of the amp is another piece of the puzzle. If you are using a tube amp, you might need to have it pretty loud to get the tubes to work how they should. If you place a microphone very close to a blasting loud amp, sometimes it actually sounds small when recorded. I have done sessions where the amp was cranked and the mic was almost 2 feet away! But in a smaller room, the room acts as an extension of the amp, and it will sound much fuller than if you put up close and turn the amp down.
Also, part of positioning the mic is the axis. Are you on axis or off? If you are off, you can get a fuller sound and not add in any actual bass, because you can be pointing at the center of the speaker but not looking directly at it, but pointing at an angle. This will roll off some bright without adding lows. It's a little smoother than the straight on approach.
Shew! So many things to think about! And with double miking it's even more confusing and technical!
When you double mic an amp, you are using two different microphones to blend together and make one big sound. This involves two different mics at different distances and different placements to compliment each other. Usually, you have one mic that is your main sound and a second that works to make the main one sound better. With that main mic, you will go thru all the steps and possibilities I have already talked about when using one microphone. Then the fun begins.
With your second mic (and hopefully an assistant!), you will begin to shape the overall sound by adding in additional textures. I almost always double mic the amp (as well as split the signal, but that is another article!), and I couldn't do it without my assistant. His job is to go into the live room while the guitar player is playing and move the position of the secondary mic around in front of the amp while I listen to the result in the control room. All he is doing is watching me for a signal and then he stops moving the stand. He comes in the control room, we listen and sometimes he goes out and moves it a little more. Not only are we listening for a good blend, but we want to make sure the phase relationship between the two microphones is the best it can be. Our goal is to get a great sound from the start, so that in the mix we just put the faders up and it's done. No compression and very little EQ, if any at all.
So, to me, single miking of an amp is ok, but limiting of what the overall sound can become. You have no secondary microphone to augment and compliment your main sound. Sometimes one is all you need, I won't argue that. I have done many a session with one mic on the amp, but I have found that my best guitar sounds have come on sessions that I took the time to not only add an additional mic, but find the correct position for it, so my main sound has more color and depth to it naturally instead of trying to fake it in the mix.
Well, that's it for now. Don't forget that you are welcome to stop by and tour our facilities anytime. Just give us a call at 859-335-8440 (if you're local) or TOLL FREE at 877-335-8440 to set it up, so we can give you the ultimate LIRCo experience. See ya next time!!!
Head Engineer, LIRS