Take the fear out of miking electric guitar amps with this step-by-step guide
By Gene Porfido
Ahhh, the electric guitar. Just the thought of it conjures up the great bands, glitter covered rock stars with their favorite axes slung low, hitting the stage every night to a sea of screaming girls and adulatory young males. You see yourself there—the wall of Marshalls at your back, six stacks per side. As you windmill into that first larger than life power chord, your pant legs blow like dandelions in the wind…
Growing up as a guitarist and eventually getting involved with live sound and recording has taught me many things about the guitar; I’ve gone to great lengths to get the Ultimate Guitar sound. This article is intended to share some of those lengths and hopefully lead you to better guitar tones than ever. There’s also a companion article for acoustic guitar that you’ll find here.
The most important issue in getting good guitar tone is all in the fingers: the way the guitar is played. 20 players can pick up the same axe plugged into the same amp without changing one knob on anything, and each will get a distinctly different tone. The sound will be similar, but the tone will change; more on the differences will follow.
That’s Lesson One; Lesson Two is that every guitar is different. Some guitars are fast as hell, others are slow and sweet, and others seem to fight every note you play. A big part of getting the right tone is selecting the right guitar—as is the case with every other instrument.
A Fender Tele in the verses, a Strat for the pre-chorus, and a third track of distorted Les Paul mixed in the chorus… Switching or adding different guitars can be one of the easiest and most noticeable ways to add variety to your palette of guitar sounds—if the music needs it. Sometimes even the cheapest piece of wood has such a radically different sound that it can add a vibe to your track. I’ve managed to keep a bunch of inexpensive guitars, including a few nameless super-cheapo models, in my collection over the years. One day I pulled out a $50 Strat copy for a solo track, and to this day it has my favorite lead sound over anything I’ve ever recorded.
Tone also depends on the strings, and size matters. Most of the “fat tone” guys like Stevie Ray played big fat-ass strings, at least 10s (first string) and preferably 11s, 12s, or as Mr. Vaughn chose, 13s—which is like having a strand from the Golden Gate Bridge beneath your fingers. Go up in size from, say, 9s to 10s, you will notice a difference—for the better.
A guitar’s ‘sound’ is something identifiable. Just as you can often recognize the sound of a familiar band from the first note in a song, after a while you just know the sound of, say, a Marshall vs. a Mesa Boogie amp or a Strat vs. a Les Paul or even just a distorted vs. clean sound.
‘Tone,’ on the other hand, refers to the feel. 20 guitarists who plug into the same Marshall stack all get a Marshall sound. But some will be a bit sharp and piercing or flat and muddy, a few may have bright but mellow tone, or they may be warm and sweet.
This all comes from playing style, how they pick or pluck the strings, where they hold their picking hands on the guitar—up against the bridge or across the rhythm pickup close to the neck, muffling the strings slightly or letting them ring true. How hard they pick, what angle they strike the string, how hard they lay those flying fingers down: soft as snow, or like they’re grabbing a size 34 Louisvillle slugger. Guitarists spend years perfecting their tone.
Before we get into amps and mic selection, there are a couple of things to bear in mind. First, if it doesn’t sound good at the amp, chances are really good that it isn’t going to sound good on the recording. Sure a great engineer can work miracles, but it’s imperative to have the tone you want at the amp before even thinking of putting up a mic.
Second, great guitar sounds don’t just happen on their own. Like everything else, they require experimentation and the time needed to experiment.
Finally, it’s important to realize that this is a living, breathing instrument. Lots of factors come together to create the sound: the player and guitar, the amp, microphone, placement of the amp and mic, the room, what you record through and onto… as well as the temperature and humidity. I’m not kidding. The temperature affects how sound travels through the air, it affects the wood and metal strings of the guitar, even the speakers.
After the player and the guitar, the amp makes the most difference to the tone. Selecting an amp that fits a guitarist’s style can take many years of buying, borrowing, and listening to different setups. Fender, Marshall, Hiwatt, Mesa Boogie, Ampeg, VOX, and Hartke are just a few of the many companies that make popular amps, and they each have a sound that’s identifiable and sought after for various reasons.
Amps come in many shapes, colors, and sizes, with tube heads (heads = electronics), transistor heads, and hybrid preamp and output sections. Some heads are known for massive distortion, some for that perfect classic crunch, some for a warm tasteful jazz sound, while others combine all three and do it well.
Cabinets play an important role in the sound, and they’re interactive with the electronics in the head. A 4 x 12 cabinet made by Marshall will not sound like a 4 x 12 Hiwatt, just as a 100 watt Marshall head isn’t the same as a 100 watt Mesa-Boogie.
Open-backed cabinets sound different from closed cabinets. They can be manipulated in the room, specifically in the corners, to get more bass and a nice round sound that’s good for jazz, country, and light rock. However, the closed-back design, especially the Marshall, has great chunky bottom; it’s a rock and now metal standard. Stacks (two cabinets stacked one on top of the other) make a classic setup that gives the player a chance to hear him or herself better on stage. (Plus they look cool, which is very important!)
The bottom line is for the player to pick an amp that will help convey what he or she is trying to say with the guitar. If you’re operating a for-hire studio, even a small selection of great amps can be a very appealing draw for clients.
The other possibility is to record with no amp. There are a lot of boxes and gadgets available that give great sound without one. That’s right, Direct Inject (DI) right into the console or tape machine.
While I certainly haven’t tried every single one on the market, I’m very taken with the Tech 21 Classic SansAmp. It’s incredible what a little EQ and a good guitar can do with this box. It comes with a collection of presets that mimic all those famous amps, and it does a damn good job of it. I’ve directly compared it with the very same amps it emulates, and it is entirely possible to match the real thing so closely that no one will know what’s what.
There are many other stomp and rack units out that add all sorts of cabinet and amp simulators with effects and digital outs. Many of them also include some excellent effects. However, there really is nothing that can match the feel and interaction a player has with a favorite cranked amp. A feel like butter, feedback with the slightest move towards the amp, and great tone… But what’s even better is also having a guitar processor/amp emulator around. It just gives you more options for getting a great sound, so why not look into both?
If you have the tracks to spare, in fact, it’s not a bad idea to record guitar both through the miked amp and directly into the recorder. You can run the DI sound through another amp or guitar processor before or during mixdown.
Mics and placement
Lots of mics work well for recording electric guitar amps, and they can all produce different colors. But throughout recording history, a few have become favorites.
The staple of rock guitar is the Shure SM57. It just has the right presence peak up top and a pretty even midrange that brings out the best of an electric. Another classic is the Sennheiser MD 421, which is often used together with a 57 for close- or near-miking the cabinet. Both of these are dynamic microphones, and there’s a cottage industry in dynamics that perform the same function but have their own sound, like the Audix i5, LEWITT MTP 440 DM, and Telefunken M80.
The AKG C414 is a famous condenser mic that some people might consider too clean for rock guitar—or looking at it from the other side, it’s an excellent clean-sounding guitar mic and a favorite room mic on any amp. Moving upscale, the Neumann U 87 and U 89 are both great room mics that can also capture great guitar tones up close. The same goes for the old U 47 fet and lots of other condenser mics from ADK to Wunder and everything in between.
Another longtime favorite is the Sennheiser 609, or the newer e609. This is a great close mic that’s also good about six inches back. Some engineers like the AKG D12 or D112 (usually kick mics) to get more bottom, and the beyerdynamic M 88 works well. Depending on the tone you’re after, many less expensive mics like the Audio-Technica 20 Series or RØDE NT1 can range from acceptable to awesome. The latest Audix mics are also really good and seem to be gaining in popularity, especially for live miking, and new companies like Aston and Roswell Pro Audio are making fantastic mics with entry-level prices and great tone.
Ribbon mics like those from AEA, Cloud, and Royer Labs (watch those SPLs—don’t want to ruin the mic!) and various tube mics are often used, and there are so many new tube mics available at reasonable cost these days that finding one you like shouldn’t be too hard. You can (and should) try almost anything, but if you start with a Shure SM 57 and an Aston Origin or Roswell Mini-K47 and a couple of mic stands, you are well on the way to getting good recordings at a budget price.
Placement is essential. The standard mic placement is close up to the cabinet, as close as you can get without actually touching the grille cloth. Even the slightest contact with the cloth can cause strange buzzes and fuzzy vibrations that might trick you into thinking there’s a blown speaker. So leave some space; anywhere up to about six inches back gives the close-miked sound.
Where you place the mic on the speaker also has a great impact on what it picks up. Most of the top end and upper mids come from the dome at the center of the speaker. If you’re looking for a hard cutting midrange or trebly tone, place the mic perpendicular to the cabinet right in front of the center of the speaker.
My personal preference is to mic closer to the edge, which tends to give a rounder tone—that is, unless I’m dealing with a muddy sound to begin with. Usually I point the mic a little off center at a 5–15 degree angle. This also helps to round the sound, as the sound waves are not hitting the mic head-on. Placing the mic directly on the speaker edge will get you different tones yet; in fact, changing the placement by as little as an inch in direction or angle can bring audible change. It helps to have an extra hand available in the studio to move the mic while you listen to your monitors.
Using two and even three or more mics is also common—in fact some engineers would have it no other way. For example, you could try close miking with an SM57 and (my favorite combo) adding the MD 421 about 6–12 inches away from the cabinet pointing at the same speaker or another speaker in the array.
Be careful about putting the mics too close to one another, because you can run into problems caused by the sound arriving at each capsule at a different time. These different versions of the same waveform either cancel or stack up at various frequencies when the mic signals are combined, resulting in a comb-filtered sound that isn’t pleasant.
The famous “3:1 Law” is a rough rule of thumb for avoiding this problem. It says that a second mic has to be at least three times as far away from the first mic as either mic’s distance from a source. So if two mics are each an inch from the speaker, they should be must be at least three inches away from each other. And so on.
Rules of thumb are not to be taken as absolute, so that’s not to say you can’t put two mics close to each other using tightly focused hypercardioid patterns. And tilting the mics away from one another can minimize or eliminate the problem. So can using the polarity reversal button on a mixer, or better yet the very short variable delays built into most digital recording devices (including a digital mixer’s channel delay, a digital tape machine’s track delay, or the equivalent in a digital audio workstation).
I’ve seen guitar tracks almost completely disappear when a second or more often third mic is brought into the mix. You can try polarity reversal or delay on the offending channel, but proper mic technique should prevent this from happening in the first place.
Getting back to speakers, be aware that every speaker sounds slightly different. One may be a little brighter or muddier than the next. By spending a few minutes listening to each speaker in a cabinet (either in the room or on a recording made for the purpose), you can pick out the one you like best and make that your main mic spot. Then you could add a third mic in a different close position, perhaps on a different speaker.
Room mics and more
You should also consider adding a room mic to capture ambience—anywhere between a couple of feet back and the next room. There are countless possibilities.
One setup that’s worked for me is with the amp at one end of a live room, and then in studios with wooden floors you can get way back with a stereo pair of room mics (or just a single one if that’s what’s available). Another setup is with an AKG C 414 pointed straight down onto the wood floor from about three inches above it, anywhere between three and ten feet back into the room. With a loud amp you’ll always get some wicked tone bouncing off the floor.
Placing a good-quality condenser mic in the room, either in cardioid position (directional patterns pick up mainly where they’re pointing) or omni position (to get more of the whole room) gives you many choices. Listen to older Queen records like Night at the Opera or Queen II, for example, and you’ll often hear the room on Brian May’s guitar.
A room mic on its own can really change the sound dramatically. There’s nothing like a completely different mic placement on a new guitar part to bring depth and color to your song.
Don’t be afraid to use any available space, either. Closets, laundry rooms, and especially large open spaces like loading docks or hallways are excellent for bringing live sound to your tracks. Two cabinets, one in a dry room and another in a live room, can get two completely different tones from one guitar. In fact, one or two room mics placed in different spots in the same room often make a big difference. The whole point of this exercise is to widen the palette of sounds available at mix time, so you can make your guitars capture attention while best serving the song.