Before you place a single mic, be sure that you understand your guitar, amp, and speaker cabinet
By Frank Marra
I have been recording bands for more than a decade, working with everybody from major-label bands to high school kids around the corner, and I am always surprised by the fact that most musicians do not have a very good grasp of how their equipment works, or how to get the sound they want from it. Most of the time, I can show them that the sound they want is right there in front of them. They just didn’t realize it, or know exactly how to dial it in.
While this article is primarily for bands just getting started or for engineers without a wide range of experience, I hope everyone will find something useful. I’m going to address the instruments that probably frustrate more rock musicians and engineers than any other: the electric guitar and bass.
A great guitar sound starts with the right guitar for the job. I could easily write an entire book on the differences between guitar and bass types and when to use them, but for the purpose of this introductory article I’m going to dive straight into talking about pickups. There are two main kinds of pickups, single-coil and humbucking, and they have a huge effect on a guitar’s sound.
Single coils are mostly found in Fender Stratocaster and Telecaster guitars. Gibson also makes a pretty popular single-coil called the P90. You can get anything from a punchy midrange sound, like the P90, to a bright and twangy sound, like the Tele. Single coils respond to your playing style, with a tone that changes as you play gently or aggressively. The only downside to the single coil, if you can even call it a downside, is that they can produce hum when near sources of magnetic interference. Some may find this to be a bit of a problem, while others may find it adds to the character of the sound. To some extent it can be controlled with gating or EQ, but you may want to simply live with it in order to preserve the real sound of the guitar.
The other commonly used pickup is the humbucker, which consists of two single-coil pickups, out of phase with each other. The two coils effectively cancel out each other’s hum. Humbuckers do not sound like single coils, though—they have a louder output, and tend to be fatter and rounder sounding. The most famous guitars with humbuckers are Gibson Les Pauls and SG models, but there are many others.
There are many schools of thought on when to use each kind of pickup. Some people think that single coils sound better clean, and humbuckers sound better distorted. There are even guitars that offer both at once for a wider palette of sounds, or have a coil tap switch that can turn a humbucker into a single coil by turning off one coil. Which is best? There is no right or wrong. Play each and see which one best fits the particular song you’re recording.
This bring us to the next part of the guitar to pay attention to, the pickup selector and tone/volume knobs. Most guitars with more than one pickup will have a switch to choose pickups or combinations of pickups. The neck pickup will always be warmer and bassier, while the bridge pickup will be punchier and more trebly. While Eddie Van Halen popularized guitars with a single volume knob and no tone controls, most guitars have volume controls for each pickup and perhaps a tone knob for each pickup as well. I often see guitar and bass players just turn everything up to 10 and play, but there are a plethora of sounds that could be achieved by spending just a couple of minutes turning these knobs back and forth. For example, when I am playing a Fender Jazz Bass, I find that if I turn the volume on my neck pickup down by about 25% so the bridge pickup can come out front, I get a really nice punchy growl that I think sounds awesome.
Once you’ve chosen a guitar, then you have to think about how playing technique affects your sound: playing with a pick vs. playing with your fingers, and how moving closer to the bridge or neck will affect the sound. While some of you may think that this only pertains to bass, it is equally important for guitar players. Playing with a pick is going to give you a much punchier and more defined sound than playing with your fingers. Playing with your fingers is going to give you a rounder sound, and sometimes a cleaner, clearer sound. I find that while playing with a pick, some players will accidentally hit muted strings that they don’t mean to. This adds unwanted and unremovable noise in the recording. Playing closer to the neck will give you a rounder sound, while playing towards the bridge will give you a punchier sound.
Remember that unless you’re looking for a very specific (nasty) sound, you’ll always want to start with a guitar or bass that has fresh (or reasonably broken-in but not dead) strings, that has been set up properly by a tech or a knowledgeable guitarist. They sound clearer, stay in tune longer, and just yield better tracks.
Now that you have the best sound coming from the instrument, you need to play it through something, so now it’s time to discuss amps and cabinets. A great guitar sound can still be ruined by the wrong amp or cab.
The two amp head types are solid state and tube. Solid state amps are based on semiconductor circuits. They start out quiet and clean, introducing almost no distortion until they’re deliberately overloaded. The vacuum tubes in tube amps can make them heavier, less sturdy, and hotter-running than solid state amps, but add a unique warmth and richness at all gain levels. The debate over which sounds “better” is something we really can’t address here; there are great amps of both types out there, and lousy ones too. Nothing can replace your ears—do some research and find what is best at giving you the sound you want for a given track.
This brings us to speaker cabinets, which come in many different configurations: one, two, four, or even eight speakers, of many different sizes. The most commonly used cab speaker sizes are 10″, 12″, or 15″. The bigger the speaker and the more surface area it has, the lower the frequencies the speaker can throw at significant volume. This is why 12″ speakers are warmer than 10″, and 15″ warmer than 12″. Multiple smaller speakers will produce a tighter, more contained sound with significant volume—that’s why many bass players like an 8 x 10″ cabinet vs., say, one beastly 18″ speaker. The type of speaker has a big effect, as each model has its own tone. Again, do research and make choices based on the sound you hope to achieve; YouTube videos don’t always have great audio quality but they can let you hear many different possibilities in a hurry.
The last thing I want to talk about is impedance. I was taught the analogy of water flowing through a pipe between the amp head and the cabinet; the lower the impedance, the wider the pipe. Speakers in a cabinet are wired in parallel; if you put two 16 ohm speakers in a cabinet, the cabinet’s impedance will be 8 ohms. (Two pipes beside each other is like one bigger pipe, right?) Four speakers gives you 4 ohms and eight speakers give you 2 ohms. Usually you don’t have to do the math yourself; the actual impedance for the cab should be marked on the back. Many amp heads have the ability to run into multiple different impedances; the usual rule is to match the head to the cab for the most efficiency. It is possible to deliberately break this rule, overloading the head to get a more “gainy” sound; I did a session recently where the guitar player played through an 8 ohm head into a 16 ohm cab, and we got some thick distorted guitar sounds. This is risky, though; you can bust your tubes or fry your amp, so use caution before you ruin your or anyone else’s equipment.
Know your guitar, amp and cabinet, and know how to set them up and use them effectively, and your recording sessions are much more likely to yield great-sounding tracks.