THE SOLO PERFORMER: "Plugging In" Your Acoustic Guitar

Written by
Michael Johnson

Musicians have become gadgeteers today. Have gone from the extreme purism of insisting on friction pegs for flamenco guitars and refusing to use a tuner because it's "cheating," to extreme dependence on electronics for their sound, musicians have so many options that choosing and using wisely is an art form itself. Today, you can use your guitar to trigger a synthesizer, turning your acoustic sound into violins, horns, glass breaking, frogs dying, or anything else you might want. The catch is that the toys are difficult to use tastefully.

Now despite the fact that my father says that country music is "just a bunch of guys who sing through their noses by ear," living in Nashville does have its up side. Here the amplified acoustic guitar reigns supreme. There are many talented players, builders and repair whizzes in town, dedicated to the improvement of guitar sound. I've mucked around for years, trying to find a good wired setup for my guitar. It can feel like a never ending quest—largely because everything gained seems to be at the expense of something lost. A microphone inside a guitar sounds like—you guessed it—a microphone inside a guitar. You can hear the sound reflecting off the inside surfaces. If you put foam rubber inside your guitar to try to eliminate feedback, it sounds like you have foam rubber inside your guitar. If you cover the sound hole to minimize the feedback, you have a confined, covered sound, etc., but the science is improving.

Here are a few general ways people go about electrifying an acoustic guitar:

1. An external mic. The external mic sounds most realistic of all, but its usefulness is limited. It's difficult to keep a constant distance from the mic in live performance, and when you move around, you create changes in the sound, especially the bottom end. Some of the best and some of the worst guitar sounds I've ever heard have been created by external miking.

In the studio it's a different matter. It's easier to control the distance problem there, plus I found that the gear I would bring in to reinforce my sound would tend to be noisy when inspected under the microscope of a state of the art listening situation.

2. A bridge pickup, or other type vibration sensing device. Bridge pickups are mounted under the saddle of the guitar. Have a repair shop do it. There are several good brands to choose from. They work well but you can get hold of a bad one. You'll know right away if the relative string volumes are not balanced enough. Have them send it back.

3. A magnetic pickup mounted across the sound hole of a steel string guitar. There are many famous ones. One down side is that they often accentuate the B string volume. Even the brands that compensate for it can be trouble. Also, magnetic pickups tend to sound more "electric"—that is to say, less acoustic.

4. An internally mounted microphone. A small lapel type mic—a common choice is the Shure "SM-98" but again, there are several great ones you can use. What they generally have in common is a low end roll off and the ability to withstand a lot of sound pressure. Typically they are mounted just inside the soundhole, parallel to the surface. As seen from the front of your guitar, with the neck pointing up, the mic is often placed at about 5 o'clock, pointing to the 11 o'clock position.

5. A combination of some of the above.

Generally speaking, microphones render a believability to the sound, and pickups provide a fullness and a longer sustain. In terms of minimizing feedback, it's the pickup that levels the playing field, allowing you to compete on stage with the volumes of other electrified instruments.

Okay, once the guitar installation has been done, the signal needs to be preamplified, and probably equalized a little, before it's heard.

There are now several types of acoustic guitar preamplifiers, solving problems in different ways. For example, taking your internal mic and mixing it with your bridge pickup, using a stereo guitar cable. You can drop some bucks here. These units are designed, at their inputs, to accept the different strength signals generated by a pickup and a microphone, allowing you to treat them independently, then enabling you to mix the signals together into a line level output. They include several types of outputs, so you can send a different signal to your monitor mix, if you want, and add reverb, delay, chorus type units, etc., to your sound. If you own a human to whom you can pay money to carry heavy things, you can travel with your own rack of unlimited effects.

A combination of signals often helps to mask the down side of each. The true colors of a bridge pickup by itself are dreadfully apparent when heard through a TV speaker—a thin, quacky sound. A well placed internal microphone together with a bridge pickup can squeeze through sounding fairly realistic. Television is probably the worst case. (Incidentally, if you haven't done TV, you should know this. Television producers, with the exception of a cherished few, couldn't care less about sound. They will have you working through a microphone clipped to your shirt collar to pick up both your voice and guitar if you're not assertive. Their job: "If it looks right, it's a wrap!" You will have to fight for your sound on TV, especially local TV.)

A simpler setup, and one which works 90% of the time, employs the use of a bridge pickup sent through a couple of devices that sit at my feet on the floor. The whole rig is so small it fits in the side pouch of my guitar case, cables and all. I keep it very simple. There are several good battery powered preamps, equalizers and simple effects available for cheaper than the larger A/C powered 19-inch rack mountable equipment.

Incidentally, if you are a believer in the floor box stuff, be aware that your sound is at the mercy of the condition of the 9 volt batteries inside the units. I carry a little battery tester with me, and it has come in very handy.

Whichever way you decide to preamplify your sound, I suggest you then use an "A/B Box," (they cost $50 up to $100). The 4"X4" foot switch gismo is just a little routing device. Using the A/B Box, you have the option of tuning without the crowd having to hear it, by muting the line that goes to the main speakers. Keeping your tuner on a separate line is also good because everything you eliminate in your chain is one less coloration and deterioration of the sound. Another use: an A/B Box would enable you to plug two instruments into it, then choose which one to send to the P.A., turning one off while engaging the other, if you have that need. If you do get an A/B Box, buy one that's "active," that is, one that's powered by its own 9 volt battery. This helps prevent "pops" when switching.

I'd also suggest you get a chromatic tuner, ($75 to $100, but worth it). Chromatic tuners are made such that you don't have to change the settings to tune each string.

Wiring your guitar for sound will probably force you to change your playing style. An internal mic will even magnify shirt sleeve noise, not to mention your previously hip sounding taps, click, bops, thuds and all the other quirky percussive ticks you've developed as time keeping devices to keep your hands occupied when not playing the strings. A bridge pickup will accentuate any activity around the saddle. So if you're in the habit of creating a backbeat with the heel of your hand across the saddle, be prepared for an explosion!

In fact, working with pickups and mounted mics, etc., may make you a cleaner player. It gave me a much healthier overall approach. Playing percussively can still be done effectively, but you might have to relearn the skill. Maybe that's just as well. A little bit of that bongo-guitar stuff goes a long way. If your guitar looks as though you've used it as a shield, maybe you should take up the drums.

Use and Abuse:
Sometimes enough is too much. The overuse of reverb is the most common abuse. Try to achieve a reverb that simulates the size of the room you're in, if that room were "wetter" sounding, with more reflective material on the walls. Your audience knows where they are, and they are more discerning than ever about good sound, so if you try that lounge thing on them, they'll know. You don't have to be Elvis (unless, of course, you are Elvis). It's tempting to use too much. On the other hand, if you're a purist and you like it as dry as a puppet fart, that's distracting too. What I'm saying is that it's difficult to be appropriate. Try to use just enough so they'll feel it but not really hear it. It shouldn't be a noticeable thing. Likewise, incessant use of choruses, delays, harmonizers, flangers, etc., is fatiguing. Like waking up inside a cheap sci-fi movie with no way out. The effects may hide some inadequacies, but they will definitely mask your qualities too.

It is hard on the old ego to discover that what you thought was a great sound was actually bass heavy, rippingly bright and way too loud for your listeners. There is always more to learn. Humbly, here's a hint: have a long enough cable on your guitar so you can step out and hear the speakers from in front. Solo performers often have to trust the judgment of people who may not know, or care, what it should sound like. Either that or they have made their own decisions based on what it sounds like from the stage, that is, from behind the speakers. Thus the sound they hear is a distorted version of what's really going out to the audience.

In the end, no pickup, effect unit, or any other dang deal will work for you if you don't listen to what it's doing each time you use it. The "set it and forget it" method doesn't get it. Situations change from room to room, day to day, even hourly, and of course, you will be listening differently too—it still amazes me the times that the monitor sound will suddenly "unfog" because I will have learned how to hear in that situation. That is not to mention that your settings may have been accidentally changed. What fun.

I know I've opened Pandora's Box here. But don't be intimidated by the task. It's much easier to understand than it is to explain. You'll see when you're on the path yourself. Break a leg.


Performing Songwriter - Volume 2, Issue 8 - September/October 1994

More of Michael Johnson's Solo Performer columns