By Dave Eichenberger
Playing an acoustic guitar isn’t that much of a problem if you’re performing in a solo or duo context: just plug in the guitars to an amp or a mixer and rock out, right? Actually, that works just fine, but when playing with a much bigger group (or miked acoustic drums and loud amps on stage), problems get, um, amplified quickly. Understanding how to mix an acoustic guitar within the context of a loud band is a great skill to have, and this article will give you a few suggestions to try before smashing that beloved D-35 into the Marshall stacks.
It Starts with the Wood
While we have articles about the different acoustic pickups we offer, it all starts with the wood. Acoustically, we have heard for years that the best acoustic guitars are made with a solid top. This is true, and I would stretch that to also include a solid back and sides, as well. Solid pieces of wood tend to vibrate more than plywood, since they are lighter and thinner. That being said, the best plugged-in acoustic tone doesn’t always come from the best sounding acoustic guitar. In fact, a top that vibrates a lot is probably the opposite of what you want in a stage acoustic guitar. Deeper-bodied acoustics which sound rich and full have the same problem when amplified: too much sound rolling around in that body, getting the wood to vibrate usually causing howling feedback. I have found that the best onstage acoustics generally don’t sound that great unplugged. If they are only unplugged for practice, it will be fine. For recording, go ahead and use the fancy Grand Auditorium. But live, you might choose something that is easy to stand with, avoids feedback, and gets a sound that can be heard through the dense mix of the band without feeding back.
Then, we have the pickups…
Good soundhole pickups are a start. Soundhole pickups don’t sound like a miked acoustic, though, and generally work by sensing the magnetic property of the strings, like electric guitar pickups. So, while the wood and body style contribute to the sound, they don’t define it. For a loud band, I like the sound of a soundhole pickup in a thinner, laminate body guitar, as it actually rejects feedback. The laminates of the wood suppress the vibrations, but we aren’t going for acoustic complexity when bashing an acoustic guitar with a loud band. Soundhole pickups also work well into a guitar amp (acoustic or electric), as well as direct into a PA. Remember, we aren’t going for pristine audio translation of the guitar’s acoustic sound here, but a simple way to get the sound in the mix without feedback issues.
Pickups like the MagMic are great if you have a nice, solid wood guitar that could benefit from a microphone capturing the acoustic sound as well as a soudhole pickup. They work best when there isn’t an onstage amp, or you are using in-ear monitors (IEMs).
Piezo pickups, like the Wavelength series work by sensing the pressure of the strings on the bridge. They do have a different sound than soundhole pickups, and are a good choice if you want a permanent installation. Again, piezos, which are common in many electric-acoustics are also prone to feedback. It is usually caused by loud stage monitors, and instead of the high-frequency screeching, you tend to get low-frequency howling at stage levels. Either are not pleasant.
What about pedals?
Effects on acoustic guitar are no different than pedals on electric guitar. Acoustic guitarists are free to use overdrive, chorus, delay, and more on their signal. You can check out a rundown of effects on acoustic guitar here. You might have to be careful with pedals that change gain because of our old adversary, feedback. However, splitting the acoustic guitar signal with a mixer and using overdrive in parallel with the clean signal (and using an electric guitar amp) for this sounds especially huge. I use pedals to also correct the EQ, but the best thing here is a good soundperson running a great sound system.
Soundperson? What’s that?
I know, having someone run sound isn’t always a luxury we have, but it helps when you are trying to amplify acoustic instruments. As we have figured out, the hardest part of amplifying an acoustic guitar in a loud band is dealing with rampant feedback. Usually this feedback has a particular frequency, and good sound mixers can EQ the sound on the acoustic guitar while drastically cutting the offending frequency. This special tool is called a notch filter, and if it is narrow enough, it can wipe out the feedback without touching the original signal. Modern monitor mixers have all sorts of EQ at their disposal, and it is pretty cool to watch them walk around the stage with their iPad finding the frequencies that are feeding back with surgical precision. This isn’t always available to us, though.
So, what’s a guitarist to do?
If we are mixing the sounds ourselves, it is a good bet to EQ out most of the low end. This is a general (really general) rule, but the chime of the acoustics occur in the mid and high-end. You won’t hear those lows when the bass and kick are going at full force, anyway. Put as little of the acoustic guitar in the monitors as you can stand. Stand back from them, as well. If you have IEMs, use them. Also, consider getting a guitar specifically designed for stage use. Some of these almost look like electrics, with no soundholes, or very small acoustic chambers. Realize that no acoustic will be great at death metal-levels and at the Grand Ole Opry. If you are serious about the acoustic tone, a feedback-rejecting stage guitar will come in handy no matter if you have a soundperson or not.
Recently I did a few songs at a gig where I had to use someone else’s acoustic with a band. It was a large body, with a piezo pickup, and to get that to sound right, we had to cut most of the lows and low mids out. I don’t have that problem with my stage acoustics, but a good sound team cut the right frequencies so it didn’t howl too much.
Do you play acoustic guitar with a loud band? How do you amplify it?