How To Mic An Electric Guitar Amplifier

With modern music (especially pop/rock music) production demands are greater than ever. The average listener expects the recording quality of your music to be the equivalent of those amazing productions you often hear on the radio. Since this discussion could take weeks and weeks and page after page, I've decided to narrow the focus of this guide to recording the electric guitar.

With any recording, getting the source right is 99% of the ballgame. This means that a great singer with great tone will sound good through pretty much any microphone. This means that a great sounding violinist with a great sounding violin in a great sounding room will sound this way through any functional microphone. Granted, some microphones will impart their character onto the source (for better or worse), but with any operating microphone a great musician will still sound great.

So with the guitar (and anything else you intend to record), it's important to get the instrument doing exactly what you want before you even bother putting a mic in front of it. You should walk around the room the amp is setup in to hear exactly what is going on. You might find sweet spots in the room. You may try actually moving the amp in a few different places in the room.

In my first recording room (which happened to be very small and very unideal for recordings), I noticed that moving an amp just a few inches had a dramatic effect on the low end coming out of the amplifier. I later learned that this was quite normal for small rooms with no acoustic treatment. (Just a side note, if you are planning on doing treatments for your room, skip the foam stuff. It probably won't help. In many instances, it will make the problem worse. Try a search for "bass trap" or visiting www.recordingreview.com). So exeriment greatly with the amp before you get serious about microphones.

In fact, I recommend that you mess with the tone quite a bit just to see. You could always settle for the tone already on the amp, or you could push the highs up too high to see where they end up. You could pull the highs down too far to see where the tone ends up. Eventually, you'll find a middle ground that keeps your perspective out of the way.

The type of guitar you use makes a big difference on how the amp will sound. This is no secret. However, many people get in a rush when recording and think that adding some sort of effect or plugin on the computer will get them what they are looking for. If you find that you are not happy with a given guitar, maybe you should try plugging in a different guitar just to see. Try doing something off the wall or downright wrong. You'd be amazed at what kind of recordings you could get with a Telecaster through a Mesa Boogie Rectifier. I've heard success stories of acoustic guitars running through cranked Rectifiers.

When you have a tone that you are pretty confident about, it's time to pull out the mics. There are a few methods to trying out mics. You could slap every mic you own on the amp to see it it's happening for you. The problem with this approach is mic placement. Did you take the time with each mic to make sure you found the best sounding spot on the amp? You could do this with each mic, but the spot that just sings for each microphone will probably be in a different spot for each mic. I tihnk your time could be spent better.

If you are just starting out and have no idea what mic would be best for a given job, start with an SM 57. They are cheap and everyone has one. If you don't have at least one, get one used off of Ebay or something. In the meantime, grab whatever dynamic you have and give it a try. There are a number of SM 57 clones that are essentially the same microphone. Even if they are not the same mic, try them. You never know.

One trick to help choose the best spot to place the mic I read in a forum years ago. It said to unplug the instrument cable from the guitar amp, crank the amp up to very high levels, and put the SM 57 (or whatever mic you are using) in front of the speaker. Next, run the mic through some loud heaphones with good isolation. Then, with the headphones on, start moving the mic in front of the speaker. You will be amazed at what you are hearing. You will hear all sorts of changes in the tone simply from moving the mic around. The users of the forum recommended putting the mic on the brightest spot. I have not had much luck with putting a mic exactly at the brigthest spot because it can get a little bit too fizzy at times, but feel free to try it and see what works. The brightest spot may be perfect with a darker sounding amp.

My favorite trick when recording guitar amps is to use two different microphones on one speaker. You have to be aware of phase cancellation. (If you are not familiar with phase cancellation, check out my website, www.recordingreview.com.) However, when you get the mics in phase, you will have much more control off your recordings. I find that what I'm looking for when mixing is much different when I'm tracking. Sometimes I wish I could go back and change something on a tone. One rememedy for this is recording the two mics from one speaker to two seperate tracks that will allow you to blend them differently to create different tones on the recording.

I start out by placing one SM 57 on the cone. This means I put the mic in the dead center of the speaker. This sound is almost always fizzy and thin. With very few exceptions, I've found it to be a crappy guitar sound. As crazy as it may sound, that's exactly what we want. We want a track in the mix that is bright, thin crap that we can use as much or as little as we feel the mood for.

The second mic should sound the opposite. We want it to be big, meaty, and full of chunky low end. This mic ends up in different places with every amp that I use, but most of the time it can be found 2"-3" from the first mic in any direction. Sometimes angling the mic towards the edge of the speaker helps, too. This mic should sound a little dull by itself.

Now record both mics and see what you get. Listen to each mic by itself first. Then listen to both of them together. Assuming you like the sound that each mic makes (Remember, you want one to be too bright and the other to be too dull) you will experience one of three things.

1) The sound will be extremely thin sounding as if you rolled off all the low end with a parametric equalizer. This means the mics are almost totally out of phase. The solution is to push the phase button on your preamp or mixing software. This is what you want. You want the combined sound of the mics to be so thin that it isn't usable. Then when you push the phase button on one track, the tone comes to life. This is what I always go for.

2) The sound will be big and full. This sound almost means good things. If you push the phase button, it should sound like what you may have experienced in #1. If the tone totally dissapears and all you can hear is some fizz, you've got the tone down. Push the phase button back to your big guitars again.

3) The sound is weird. You are not sure what it sounds like. It's not bad, but it's not right either. Pushing the phase button only changes the tone in the mids and does not have make a big impact on the low end. In this case, some other frequency is out of phase and the low end is in tact. You need to use your ears on this one. I usually don't like to leave the mics like this. I go for #1 or #2. However, many great engineers use phase cancellation as a way of eq'ing the amps. This is highly advanced engineering, and not for the faint of heart However, if you stumble on a sound that you really like, by all means, go with it.

Well that gives you food for thought. You'll notice that we didn't talk about different microphones. The truth is if you master the techniques above, you won't have too much need for more mics. If you want to expand your mic collection, go ahead. There are a number of mics that work great for electric guitar amps. Check out my website for details.