Recording Electric Guitar
Oct 1, 1999 12:00 PM, Myles Boisen
The electric guitar ("El Gtr" in engineer shorthand) is one of the easiest instruments to record. Even a modest rig-a good guitar coupled with a decent amplifier-makes the engineer's job a cinch, offering plenty of level, a variety of easily adjustable tones, and-with most modern amps, at least-an assortment of "flavor enhancers" such as tube saturation, overdrive, and compression. In addition, the limited bandwidth of a typical electric-guitar track is ideally suited to the frequency response of affordable dynamic microphones. But that doesn't mean that using the age-old standard of miking guitar amps-a Shure SM57 shoved up against the grille cloth-is the best way to get El Gtr to stand out in a mix.
Like many engineers, I learned the basics of recording guitars by doing live sound and occasional session work. But my "higher education" began when I was hired by a blues/R&B-oriented mail-order record company, and I "had" to listen all day long to recordings from the '40s, '50s, and '60s. No matter how primitive or poor the recording quality on those old discs, I was constantly amazed by the array of exciting sounds produced by electric guitar. Later, when I started recording blues sessions in my own studio, I learned firsthand about the key elements that contributed to the great tones that I'd heard on those classic recordings.
TUBES ON 10
Nothing sounds as good as a tube amp turned up to 10. You can do this with some old amps, and they will sound fairly clean; others will explode. Use caution and keep an eye out for plumes of smoke. Newer tube amps generally have separate preamp and master-gain controls that can duplicate the gritty anarchy of yore, minus the lease-breaking SPLs. For jazz and other clean guitar styles, it's okay to turn the volume down a bit, as long as you don't "underdo" it.
But having hot tubes is only half the recipe for getting great tone. Room sound is the other ingredient necessary for obtaining a full-bodied guitar track. It didn't take me long to figure out that the guitarists on my formative blues sessions were slyly contributing to my "education" by nudging the mics away from their amps as soon as I left the room. Thanks to their clandestine efforts, my ears opened up to an entire new world of electric-guitar sounds.
I've since developed several recording techniques that are a sure cure for the El Gtr blahs. Try the following four tricks in their order of appearance, as they are progressively more complex.
SIMPLE DOES IT
Once you have the essential elements in place-a great amp, guitar, and guitarist-you almost can't help but get a great guitar tone. Crank the amp up to the appropriate level and begin with some mic comparisons. It's especially telling to audition different types of mics: for example, dynamics, ribbons, and large-diaphragm condensers. (I rarely use small-diaphragm condensers for miking guitar amps; on the other hand, I've found that almost any microphone will strike gold once you find the right spot for it.)
My favorite dynamic mics for this application are the Sennheiser MD 421 and 441 and the Shure Beta 58 (which has a fuller sound than the SM57). My favorite ribbons are the Royer R-121 and Coles 4038. For large-diaphragm condensers, I lean toward tube models, in particular the Lawson L47MP and Neumann M147.
Start with all of the mics clustered together three to six inches from the grille cloth, pointed at the center of the speaker. On a multiple-speaker cabinet, don't assume that all the speakers sound the same. Rather, listen to each of them at a sensible volume, and then mic the one that sounds best. If the speakers sound alike, a miking position close to the floor will generally provide a little more low end.
Back in the control room, audition each mic, preferably as the guitarist plays along with the other instruments. Listen carefully to how each microphone sounds on its own and, more importantly, to how it works in the mix. Usually, one microphone will come up a winner on the first pass. Don't stop there, however. Instead, leave the "winning" microphone where it is and experiment with the placement of the other two mics. Time-and mic selection-permitting, you may also wish to do a second round of testing with other microphones.
The key elements of mic positioning are distance from the source and orientation to it. Moving the mic closer to the amp provides more definition, increased highs and lows, and less room sound. As you pull the mic back, the sound becomes less detailed, more "midrangey," and more blended with the ambience. Depending on the room you're in, a distant-miked amp may gain a natural presence and unique character in the mix, despite an apparent decrease in definition. On the other hand, placing the mic too far back will result in a washed-out, murky, or hard-to-control tone.
Mic orientation, or the angle of the mic in relation to the speaker, becomes more critical as the mic is moved closer to the amp. Pointing the mic at the center of the cone will yield more active highs and better transient detail but fewer lows. As you move the mic toward the outer rim of the speaker, maintaining a 90-degree angle with the grille cloth, the low frequencies gradually increase because of proximity effect and other factors, resulting in a sound that may be warmer, softer, or more powerful. Many engineers like to blend these complex characteristics by angling the mic between 30 and 60 degrees off-axis from the center of the speaker.
Of course, it is vital that you experiment and let your ears be your guide with all the techniques mentioned in this article. Don't hesitate to try a crazy placement or an unusual mic such as a PZM (pressure-zone mic). With persistence and a bit of luck, you will likely discover some tricks of your own.
Once you've mastered the intricacies of single-transducer miking, it's fun to start working in stereo. For true stereo recording, you need a matched mic pair as well as a twin-speaker amplifier, preferably one with built-in stereo chorus and vibrato (such as a vintage Magnatone or a Roland Jazz Chorus). Two separate amplifiers fed by the same stereo delay or multi-effects unit will also work.
Mic each speaker or amp, pan the two channels apart, and let the effects work their magic. Hard-panning to the extreme left and right produces the most dramatic results; should this prove too dizzying, try panning one microphone toward the center, or move the tracks toward a more centered symmetrical position.
You can use similar two-mic techniques, minus the effects, on a single amp to capture a variety of larger-than-life guitar sounds. One trick that I stumbled upon involves miking a twin-speaker amp with two mics that are close in response, but not matched (see Fig. 1). The first time I tried this, on a session with guitarist Paris Slim, I used an Electro-Voice RE20 and a Sennheiser 441.
Place one mic on each speaker at the same distance and orientation, and check the pair for phase cancellation by panning them to the same spot and listening in mono. The minute differences between the speakers, mics, and mic positions, combined with double-tracking, creates a monstrous presence when the tracks are hard-panned in the mix, and opens up a world of possibilities for separate EQ and effects processing. If you don't need the guitar to dominate the mix, you also can sum these mono-compatible tracks together to a single pan position for a noticeably bigger sound.
To capture aggressive, distorted guitar sounds, my studio partner Bart Thurber likes to use two mics in an XY configuration on a single speaker: a Shure SM57 aimed at the middle of the speaker and a Sennheiser 441 (with the high-end boost switch engaged) pointed at the edge of the cone. The SM57's signal is sent to a compressor, and the two mic signals are then mixed together and recorded to one track. This technique provides some compression for the harshest high frequencies and strong, midrange volume peaks picked up by the SM57, while simultaneously delivering full highs and lows through the 441.
Another variation on the two-mic technique involves miking the front and back of an open-backed cabinet. For this application, be sure to place the mics at an equal distance from the speaker itself and reverse the phase of the rear mic.
TO AIR IS HUMAN
Forget Risky Business (remember the famous scene of Tom Cruise rockin' out in his boxers?); this technique, which I consider real air guitar, is serious business. It entails capturing the airy, percussive sound of the plectrum strumming or picking the electric guitar's strings-either in acoustic isolation or combined with the ambient sound from the amp-and then mixing this sound with the recorded amplifier sound. The addition of just a little percussive plucking can enhance the presence wonderfully for any style of guitar playing. In my opinion, it's the greatest studio-recording innovation since John Bonham's distinctive drum sound.
The blues was my inspiration-specifically, the late-'40s solo recordings of John Lee Hooker. "Hobo Blues" is an excellent example of early Hooker on which his violent string slapping-clearly audible in a blend of amp sound, haunting vocals, and trademark foot stomping-creates an indelible realism and engaging intimacy. My recording of Paris Slim's "The Day I Met The Boogie Man" (see the sidebar "Selected Discography") was one of my early experiments with this technique. Since that time, I have used a discrete "air-guitar" mic whenever I have had an available track for it. Guitarists may initially be skeptical of such unusual miking, but it's always a treat to watch their faces light up as they listen to the monitors deliver the bright, transient sounds that they have been accustomed to hearing during their years of practicing their instruments.
I have achieved my best results with this technique when miking resonant hollow-body guitars, getting the mic in as close as possible to the guitarist's picking hand. Large-diaphragm condensers, especially the Neumann U 87 and Manley Cardioid Reference tube mic, have proven superlative performers on big-box guitars such as the Gibson ES-175 (see photo on p. 114). The small-diaphragm Oktava MC 012 and medium-diaphragm Shure KSM32 have worked wonders on solid-body instruments, most notably on improvisational-guitarist Ron Thompson's seven-string custom axe.
Mix magazine columnist Stephen St. Croix recently documented his own variation of this technique. He uses two "air" mics-one each on the low and high strings-with the resulting tracks panned hard left and right in the stereo spectrum.
An overdubbing session is ideal for air-guitar miking because there is no leakage from other instruments. I usually prefer to maintain total isolation between the two sources, placing the guitarist and amp in separate rooms. But for some production styles, the acoustic air mic can also do double duty as a distant room mic for the amp, with the ratio of pick sound to ambience determined by mic placement and amp volume. I've recorded some very hefty-sounding rock 'n' roll power chording this way, as well as a variety of vintage-style solos and rhythm parts. At the board, a low shelving or low-midrange EQ cut, combined with a subtle high-end boost around 4 to 6 kHz, will usually help these tracks jump out of the mix.
The key to capturing any kind of ambient tracks is a good reverberant space, although a narrow or dead room can also work, as long as there is sufficient distance between the guitarist and the amp. I usually put the air mic at least ten feet from the amp, positioned off-axis, or in an omnidirectional pattern to pick up as much reflected sound as possible. Placing a baffle between the guitarist and the amp will increase the apparent room size, as will making the amp sound pass through a doorway or turn a corner into another room.
Should space restrictions or volume levels make these methods impractical, try adding an air-guitar part as an overdub to a conventionally miked guitar track. The principle is similar to vocal doubling, for which the same part is performed twice; you may not be able to do this for an improvised solo, but for rhythm parts or composed lines, it's a snap. In addition, double tracking with a bright acoustic guitar or a smooth-sounding hollow body will add extra richness and some slick, big-budget zing to your mixes.
After you have the hang of mono and stereo miking, room miking, and air guitar, you may be ready for the final frontier of El Gtr exploration. The time-consuming technique that I call "multisourcing" combines all the aforementioned methods, multiplied by the infinite possibilities created by splitting the guitar output and sending it simultaneously to different amps (using, for example, a Whirlwind Selector splitter box).
When I first tried multisourcing, on a solo project by Club Foot Orchestra guitarist Steve Kirk, I used an air mic, a direct source (Manley tube DI box or speaker emulator output from Kirk's Marshall JMP-1 tube preamp), a close mic on a clean-sounding Fender Princeton amp, and close and distant mics on a cranked-up Marshall cabinet (see Fig. 2). And that was just for the first rhythm track! As you may imagine, mixing was a lot of fun, and after that day there's been no going back to the old SM57 shoved up against the grille cloth. If you dare, you can take it from there. The only limitations are your time, the guitarist's patience, and available tracks. Oh yes-and lots and lots of mics.
The following CDs, engineered by Myles Boisen, are recommended listening for the electric-guitar miking techniques described in this article.
The Dynatones, Shake That Mess (Blue Suit Records, 1999) "Bulldog" (tubes on 10) "Ace of Spades" (stereo vibrato) "Memphis Women" (air guitar) Available from www.dynatones.com
Steve Kirk, Steve Kirk Pop (SKP Records, 1999) "River of the White Lake" (tubes on 10) all tracks (air guitar, multisourcing) Available from email@example.com
Ben Marcato and His Mondo Combo Party Mix (Urgent Records, 1999) "Too Lazy to Work" and "Little Joe from Chicago" (air guitar) "Smack Dab in the Middle" (tubes on 10, air guitar) Available from www.benmarcato.com
Paris Slim, Bleedin' Heart (Globe Records, 1996) "The Day I Met the Boogie Man" and "The Candle's Burnin' Low" (air guitar) Available from www.westcoastblues.com
Ronald Thompson (avant-garde seven-string guitar), Spiritpark, vol. 3, Music for Percussion, Saxophone and Guitar (Spiritpark Records, 1999) and Spiritpark, vol. 1, Music for Solo Guitar (Spiritpark Records, 1999) all tracks (air guitar, multisourcing) Available from Spiritpark@aol.com