Here at UpFront Guitars we sell a lot of Godin and Simon and Patrick acoustic or thinline acoustic guitars. All these guitars have built in electronics, and in most cases the buyer does not ask me for advice on how to amplify it. Without a doubt, amplifying an acoustic or even the thinline Godin acoustic-electrics is a challenging proposition. Despite major advances in on-board electronics, getting a natural sounding amplified tone still takes some work. There are multiple ways to approach amplifying an acoustic guitar with on-board electronics, and here are a few suggestions we’ve stumbled on along the way:
Straight it the Mixer – For many performers, direct into the board is a very common approach. However, many mixer preamps are not that friendly for acoustics and the sound can be a little flat and uninspiring. This gives rise to the Acoustic Preamp, which is typically a stomp box with EQ parameters specially voiced for acoustic guitars. Quite often Acoustic preamps feature special “notch” filtering to help fight feedback, and the ability to adjust not only the gain but center frequency of the all-important midrange. At minimum they also serve to convert the Hi-Z 1/4″ jack signal from the guitar to a Lo-Z XLR input for the mixer. There are many manufacturers of these products including some well know names like L.R. Baggs, Radial, Tech 21, BBE and others. These products run from $129 to $500 for the Taylor K4. My feeling that going “naked” into the mixer is not going to yield desirable results, and some type of signal conditioning is needed.
Tube or Microphone Preamps – An alternative to a specific acoustic preamp stomp box is a microphone preamp. These can range from $99 for an ART tube preamp to thousands of dollars for an Avalon, Universal Audio or other high end studio stuff. In general these are tube-driven devices that are intended to offer a softer, warmer sound and natural analog compression via a vacuum tube circuit. For short money, we’ve played around with a basic ART MP Studio V3 Tube Preamp ($75) and it certainly takes the harsh edge off a piezo-based transducer, and offers some basic amount of tone shaping. Mic preamps also have lots of other uses besides acoustic guitars, so it’s a multi-functional tool. You can spend a ton of money here, so consider whether you are looking for a product for live performance in front of a bunch of drunk people, or a critical recording application.
Powered Speakers – Chances are these days that if you are playing your acoustic into the mixer, there is a good chance that the mixer is feeding a powered 2-way speaker. Powered speakers rule the world of portable and small-medium PA systems, and they also make excellent stand-alone acoustic amplifiers. For most acoustic electric guitar demos our favorite tool is a QSC K-10 powered speaker. It has plenty of power, and the full range frequency response needed to produce complex acoustic guitar tones (acoustics have a wider frequency range and more complex overtones than an electric). Plus as opposed to an electric guitar amplifier, powered speakers typically have a specific woofer and tweeter to accurately produce high an low frequencies. A good preamp, maybe a little reverb and a high quality powered PA speaker is a killer combination, even if you are also feeding the mixer.
Conventional Electric Guitar Amplifiers – As a rule most electric guitar amplifiers are pretty lousy at amplifying acoustic guitars. Mostly because the amplifiers are not designed to produce the wide frequency range needed for a natural acoustic sound. The extended high end needed for an acoustic simply is not needed for an electric guitar, or would have an electric sound overly harsh or icy. But in a pinch, some guitar amplifiers can do a pretty good job, and if you want an amp that can do double duty there are a couple things to look for. First is speaker surface area. More speakers are better, and generally smaller speakers are better than bigger ones. A 2×10 will produce a more detailed sound than a 1×12, and a 4×10 is better than a 2×12 or 1×15. Smaller speakers with lighter weight moving parts can easily produce more detail and nuance than a big 12″ speaker with a 50 ounce magnet. A midrange control is also very handy, and even better if your amp has an active (versus passive) midrange control. Shaping these critical frequencies can mean the difference between a reasonably natural sound and a honky, nasal box o’ noise.
Also, some of the earlier guitar amplifiers based on designs from tube manufacturing handbooks make pretty good acoustic amps. Why? Because they were really not “guitar amp” designs, but rather full-range tube amplifier designs adapted to amplifying guitars. Amps like the Fender Bassman make very good acoustic amplifiers because they are essentially full range amplifiers with four small low-mass speakers in a pine box. We use our Fender Bassman Ltd Reissue to check out acoustics prior to shipping, and it sounds remarkably good. However, our Dr. Z Remedy through a similar 4×10 cabinet with the same speakers as the Bassman sounds more closed and dull. The Remedy is an excellent electric guitar amp, while the Bassman origins are more hi-fi than guitar. Jason Mraz uses two blackface Fender amplifiers for his live stage sound and mixer feed, and his live guitar sound is killer. Surface area and those simple Fender schematics do a great job.
Aurel Exciters – An Aurel Exciter (such as the BBE Sonic Maximizer) use frequency dependent phase shifting and dynamic equalization of (usually) higher order harmonics to make music sound more alive, distinct, and lend a greater feeling of note separation. I really like the results using this type of effect with acoustic guitars, and it’s part of my band’s live acoustic rig. Aurel Exciters are also frequently used in the studio to perk up dull recordings without making them sound overly bright. Aphex and BBE are the best known names in this type of product, and it’s also available as a software plug-in for recording software.
Dedicated Acoustic Amplifiers – I don’t have much to say about dedicated acoustic amplifiers, because it’s been years since I’ve used one. Acoustic guitar amplifiers are optimized specifically for acoustic guitars, and typically have active equalization, and high and low frequency (woofer/tweeter) transducers. As such they are generally overly bright and unsuitable for electric guitars, and if you do double duty with your band, you’re faced with hauling two amps. It just seems more logical to bring your favorite electric guitar amp, and work out a good sounding direct setup for the acoustic.
The Lowdown – Electric guitar players are known to be obsessive about their tone, but acoustic guitars are equally if not more challenging to dial in. A warm, natural sounding acoustic guitar can add a lot of character and richness to any band. Study your acoustic setup, and give it the same attention to detail as you would your solid body. Getting a good sound make take some experimentation, but it’s not necessary to spend hundreds of dollars to spruce up your amplified acoustic tone.