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Stageworthy Strategies: How to Apply Compression and Overdrive to Acoustic Signals

Dan 'Lebo' Lebowtiz
(Image credit: Steve Jennings/WireImage)

For the past couple of columns about the post-pandemic return to performance, we’ve focused on guitars, preamps, and direct boxes. Now it’s time to address the application of dynamics, specifically compression and overdrive. 

Compression is one of the most useful but also misunderstood forms of processing in the acoustic-electric universe. Some players think overdrive is only for electric guitars, but that perspective misses the bigger picture. 

Once an acoustic guitar gets plugged in, it essentially becomes an electric guitar. Everything is on the table. Ultimately, all that matters is stage tone and the sound that comes across to the audience through the P.A.   

Applying Compression

Compression is a dynamic control that smooths out peaks and valleys, raises the overall gain floor and adds a perceived volume increase. Whether or not it’s for you depends on what you do. If you’re a big chord strummer that mostly uses a strong attack, compression isn’t ideal. It will only squash your sound and make it pump in a breathy kind of way. 

For everyone else, compression can be useful because it evens out softer and stronger plucking and strumming. It can be fantastic for adding creamy sustain without extra gain to lead passages, and it’s particularly helpful for fingerpicking because it allows individual notes to sing out loud and strong. Add too much, however, and they all run together. 

What kind of compression and how much to use is a deep discussion. Phil “Philbillie” Milner served as Bob Weir’s guitar tech and currently plays acoustic in the Jenny Kerr Band, and he has some interesting advice.

“The idea is to add harmonic content,” Milner says. “The old studio optical tube compressors, such as the Universal Audio LA2A, were the best, and pedals such as the Electro-Harmonix Black Finger have used tubes to achieve that sound. While it’s been discontinued, it can be found used if you want true tube tone and don’t mind its rather large footprint.

“The closest sound I’ve found in a smaller, solid-state pedal is the Line 6 ToneCore Constrictor, which is ideal for adding warmth to a quacky old piezo. It’s also discontinued. Recently, I’ve gotten good results from the TC Electronic HyperGravity Compressor. A few of the downloadable TonePrints are based on optical tube compressors and do a great job.

“The bottom line is to keep it to a minimum, so as not to squash the signal. Find a sweet spot for the amount of sustain – just enough to smooth things out and add that harmonic content. I set the level up a bit and use it for a lead boost.

“If you want to leave it on all the time, you’ll have to master your picking dynamics, or get a good clean boost for leads. The art of the compressor is that a little goes a long way, and if you over compress, you will achieve exactly the opposite of what you originally set out out to do.”

Acoustic Overdrive

Overdrive isn’t just for electric players anymore. Plenty of acoustic rockers such as John Butler and Dan Lebowitz (ALO) push tube amps for gain. Most use a magnetic sound-hole pickup that plays well with electric amps and pedals. 

“Lebo” swears by the transparent overdrive of the fabled Klon Centaur. He says, “At unity settings, you get exactly what goes into it. Then it can be a general level, or a treble boost or cut, and a means to add a little hair.”

Originals are rare and expensive, but myriad clones are available. Lebo mostly uses a Stigtronics Tone Vitamin on his board and keeps his pawnshop prize safe at home. Milner agrees, and says that the inexpensive Mosky Golden Horse is one of the best investments he’s ever made.

Place a compressor before a gain pedal to drive it into a silky, violin-like tone

He also suggests a hip tip: Place a compressor before a gain pedal to drive it into a silky, violin-like tone. It’s far less common but not unheard of to dial in a hip overdrive tone from a piezo pickup signal. Fender’s Smolder Acoustic Overdrive is specifically designed for that purpose. It has flexible controls and can be dialed in as either a rhythm bolster or lead tone trigger. 

In fact, Fender is so enthralled with pushing acoustic overdrive into the red lately that the new Jazzmaster Acoustasonic is set up to generate some downright gnarly distortion sounds onboard via the Acoustic Engine. As acoustic and electric lines continue to blur, remember: The only rule about overdriving an acoustic-electric signal is that there is no rule, only what works for the player and the music.