Recording Guitars: Miking Amps, Part 1
Here's another helpful article originally from the Gibson.com website...
In theory, the incredible advances in home recording thanks to digital technology—and conversely declining prices for such gear—put professional music production within the grasp of every musician. All too often, however, I encounter guitarists who are a few months into using their new computer-based “better than CD quality” systems and already on the point of utter frustration about not being able to get studio-quality results out of their gear. This new series on Gibson.com aims to help rectify that, and begins with this nugget of wisdom: however advanced the technology, you still need to learn some good, old-fashioned studio technique if you hope to record professional sounding guitar tracks.
To that end, let’s start the series with one of the most basic and crucial realms of studio knowledge: microphone placement*. It doesn’t get much more basic than putting the right mic in the right place, and while this might seem a simple and obvious process it really is an art in itself, one which can often separate the men from the boys even among professional recording engineers. That said, the rule of law in mic placement is that there are no rules—what sounds best, works. The real trick is finding the placement that really does sound best, and not just sticking the mic randomly in front of the speaker and hitting record. Great guitar recordings have been made with one, two, three and even more microphones, but let’s start with some ways of finding the correct positioning for a single microphone in this installment, and move on to a few two-mic techniques in Part 2.
The type of microphone you use will partially determine where you place it. Here we’ll discuss three basic mic types: dynamic, ribbon, and condenser. Rugged (and relatively affordable) dynamic mics like the classic Shure SM57 or Beyer M201 are typically used for “close miking,” which—just as it sounds—means you put them very close to the speaker, even as close to the grille cloth as you can get without touching. Ribbon microphones are both very delicate (other than a few designs that are able to withstand high sound pressure levels, or SPLs) and mostly pretty expensive, and most of them sound best and are most safely used at a distance of a foot or so away from the speaker. Condenser microphones, which have become much more affordable in recent years, are very sensitive and are usually used at even further distances, or as a second mic to blend in some ambient sound with that of a close mic. Many condensers can handle the SPLs produced by close miking, but will distort too easily up close and give you a harsh, crackly sound.
You’d think close miking with, for example, a Shure SM57 would be the most straightforward process of all, but changes of even half an inch left or right, up or down across the cone of the speaker will produce noticeably different tones. Many home recordists routinely place a dynamic mic right in front of the center of the speaker cone and start playing, but in many instances this captures the harshest sound from the speaker. Moving the mic to the edge of the speaker cone often yields a warmer, edgier sound, and you will hear something a little different from just about every position in between. Even turning the mic at a slight angle to the front of the speaker cabinet picks up a slightly different tone. Switch your recording system to “input monitor,” and listen through the monitors or good headphones to the amp sound produced—ideally in a different room—by a number of different mic positions as a friend or band member moves the mic around in front of the speaker. Pick the sound that works best for you… but don’t stop there. Listen to how that sound works in the mix with the tune you’re recording. All too often the best solo guitar sound doesn’t prove the most effective—the punchiest, most powerful, or most attention grabbing—when you hear it with the rest of the band.
With condenser mics, you can follow a similar process, but because you start by extending your miking distance at least a couple feet from the amp (unless you’re recording a very small amp, or one set to extremely low volumes) that means you’ve got a much bigger field to play with. One great technique for placing a condenser mic to record a guitar amp, one that was told to me a few years ago by John Paul Jones (not only the bassist for Led Zeppelin, but an outstanding engineer and producer in his own right), is to use your own ear like a mic, and stick the mic at the position in the room where the guitar tone sounds the best to you. This is ideally done with another person playing the guitar: cover one ear, and walk around the room listening to the sound in different positions. When you hear a sound that really nails what you’re trying to capture, set up the mic right there. Done.
Ribbon microphones, which are becoming more and more popular these days (and, in some cases, more affordable), are often placed by combining these two techniques. Certain models, such as high-end designs by Royer and more affordable designs by Nady and CAD, can take high SPLs. Others, such as classics like the Coles 4038, might go “poof” in front of a raging 50-watter. In most cases, ribbons will sound best at least a few inches back from the speaker anyway, and sometimes will capture the most lifelike sound two or three feet away. Again, experiment with positioning, and be sure to check what works in the track.
Here's some suggested mics, besides the ones originally mentioned in this article.
- SE Electronics GEMINI MK2 Dual Tube Condenser Microphone - you simply can't beat the sound of a classic tube condenser mic. This is a high-end, no holds barred piece of microphone history. The dual valve design means pure valve warmth from the 12AX7 input valve coupled with a 12AU7 valve on the output stage in place of the traditional transformer. The same manufacturer also makes the Z5600a II vacuum tube condenser mic, which is considerably cheaper and also excellent.
- Rode NT1-A - very affordable, and great sounding condenser mic. Great for your guitar recording, but also vocals or whenever you need a good quality, reliable condenser mic.
- Behringer Condenser Mics - for the home-studio, or musicians looking for something cheap but with good quality, you can't go wrong with Behringer's range of condenser mics. They are perfect for those who never used condenser mics before and want to try them out without commiting to a more expensive buy.
- AKG C1000S - large diaphragm condenser microphone. Great, affordable package if you're looking for a good dynamic microphone
- Shure PG57 - the SM57's baby brother. For about half the price, you're still able to get a good mic for guitar recording.
- Electro-Harmonix EH-R1 ribbon microphone - affordable ribbon mic with the quality you can expect from EHX. Offering the natural and open sound associated with the finest ribbon microphones, the EH-R1 boasts a broad, flat frequency response that shines on any instrument that requires real definition View more ribbon mics here.
*Sure, there are a lot of direct-injection interfaces that shoot your guitar sound right into your digital audio workstation (DAW), and usually offer amp and speaker simulations to boot. But plenty of guys still mic up cooking old tube guitar amps to achieve the best possible tone.
[originally by Dave Hunter, Gibson.com 01.03.2008]