A typical 'on-axis' recording setup.
Like any other art, there isn’t any one single accepted way of going about making music. Although we categorize certain traits of music – such as the key, dynamics, tempo, etc. – in order to better understand it as a science, the fact remains the same that there isn’t any true rulebook on the matter. If you really wanted to, you can craft yourself a song that is slightly flat, off-time and doesn’t follow any of the familiar chord progressions. It’s probably going to sound strange, off putting and otherworldly, but its technically still music. Now, when it comes to something much more tangible such as music recording, the rules of the game are much clearer and consistent in regards to what will work and what probably won’t, but the key word there is probably because as long as the end result is satisfactory, how you got there isn’t nearly as important, well, as far as the listeners are concerned. But for us here who like it better behind the mixer, how you got a certain result is just as important as the result itself. There might be a certain circumstance where one recording technique simply isn’t possible or doesn’t sound particularly right for a song while a different one will be right on the money. Essentially, each technique has its benefits and shortcomings. Whatever the reason may be, there’s nothing wrong with exploring your options, so let’s get to the first technique which is also the most common.
Single Mic to Amp Recording
This is probably the most common way of recording an electric guitar and many times can be the most cost effective since it only requires one microphone, one amp and recording gear. It is also by far the easiest to get right since the positioning is based off of what sound you’re going for. You’re going to need a dynamic mic for this one since it can better handle loud noises without clipping. A ribbon mic also work with this technique although I would imagine not everyone out there has invested in one.
I usually start with the mic facing the center of the speaker cone at about four inches away and then make tweaks and adjustments depending on the sound I’m going for. Facing the mic towards the center of the cone will produce of more top heavy response with a bit more treble while recording closer to the bottom of the speaker cone will give you more pronounced lows with a bottom heavy feel. You can also change the response of the mic by playing around with the recording angle. Pointing the mic directly at the speaker – known as on axis – will yield “spikier” results with more of a punch. On the other hand, pointing the mic at an angle – known as off axis – will give you a sfoter, more subdued sound. If possible, it’s a good idea to have a friend there that can move the mic around for you as you play in order to find what sound you’re looking for without having to continually stop to make adjustments on your own.
Front and Rear Mic Recording
In order to actually be able to use this recording technique, you’re going to need an open back amplifier and two microphones – a dynamic for the front of the amp and a condenser for the rear. If you don’t happen to have a condenser mic on you, you can use a dynamic mic instead, it just won’t sound as warm/natural. By placing a mic in the rear side of the open back cab you can recreate a kind of live-setting, opened room kind of feel for your guitar track. Some call this a “3D” effect but in simple terms, it’s more of a simple form of surround sound.
The front mic will be treated exactly the same as mentioned in the single amp to mic process above. The rear mic has a lot of leeway as far as placement goes but as far as a starting off point goes, try placing it about six inches away from the rear of the cab, on-axis and – most importantly – out of phase with the front mic. The blend of the front and rear mics should have more body than the single mic alone. Also, having the two mics out of phase is exactly what creates this full 3D, open room type of sound. The closer in phase they are with each other, the thinner the results will sound.
Coincidental Mic Recording
This technique is also known as stereo miking. You might have also heard of something known as X-Y miking (popular for recording pianos) which is pretty much a specific type of stereo miking, but let’s get back to recording guitar. Although this technique also uses two mics, it’s completely different from the front and rear process. First of all, this type of miking isn’t aiming for a 3D type of sound and more importantly – you will need two identical dynamic microphones.
Start the process exactly how you would with the one mic technique but just make sure that this mic stays on-axis. Grab your second identical dynamic mic and place it right next to the first at the front of the amp. Make sure you get the capsules as close together as possible but angle the second mic between 45 and 90 degrees to the first. After you’re done recording the guitar tracks with these two mics, you will still have to balance them in order to combat any phasing issues. Unlike the last technique, we want these two tracks as in-phase as possible.
Start the balancing process by having the faders on each of the two tracks panned directly to the center. Have one of the tracks set at 0db. Hit the reverse phase button on the other one. Just in case you’re wondering, the reverse phase button should look like a zero with a diagonal line going through it. Play both tracks. Start bringing the fader up (on the track in reverse phase) until the sound begins to thin and then gets thick again. Your job is to find that midpoint where the sound is as thin as possible. Once you find this spot, you can disengage the reverse phase and you should have yourself a much more pleasant and full bodied sound than using one dynamic mic alone.