Amplifying your acoustic? Here's how to get the best sound using two signal paths

Havingn separate signal processing is a huge advantage when it comes to using dual pickup signal chains. Plus it’s just plain fun! Suddenly your electric pedals become viable options for increasing the X factor of your amplified acoustic guitar tone.

In the previous Learn column, we addressed how to take advantage of the dual channels found standard on most modern acoustic amps. The concept is to capture body tones with a piezo or body sensor transducer, and get focused string tones by adding a magnetic pickup in the sound hole. Once you’re on the path to dual-signal glory, myriad new signal processing possibilities become available. The general M.O. here is to get a fat, true acoustic sound on the first signal, and process effects to your heart’s desire on the second one.

PIEZO SIGNAL PROCESSING

Some acoustic-oriented manufacturers have been developing effects pedals specifically for acoustic players in recent years. Prime examples include the L.R. Baggs Align Series and the Fishman AFX Mini Series. They’re optimized to accommodate the typical piezo undersaddle pickup found on modern acoustic-electric guitars.

That said, most pedals are designed with electric guitar signals and electric guitar amps in mind, and that’s especially true for gain pedals. Fender’s Smolder Overdrive is one of the few designed to work with a piezo signal. Ukulele star Jake Shimabukuro once told me that he specifically seeks out gain pedals with bad reviews from electric guitarists because they might be better for acoustic instruments. But once you add a magnetic pickup in the sound hole, such limitations become meaningless and new strategies come into play.

I try to keep the piezo signal as an acoustic baseline using perhaps a pre-amp and some compression to bolster the tone, and maybe a Boss OC-5 Octave in Poly mode for some bass in the bottom end. I’ll put my looper on this signal too because you only want the basic stuff on the loop. I may add any of the aforementioned effects pedals that are designed to process a piezo signal, but the primary goal is to have a robust acoustic tone that’s not too washed out with ambiance or modulation effects.

MAGNETIC SIGNAL PROCESSING

Here’s where the real fun begins. I put an array of “electric” effects in play on the magnetic pickup signal chain, starting with a wah, followed by gain and distortion, modulation (such as chorus or vibrato), and finally ambient effects, including delay and reverb. It’s cool to experiment with everything from heavy gain to spacey echoes while your basic signal remains fat and unfettered.

Most modern acoustic amps include at least a decent reverb. That’s usually the last thing I’ll dial. I generally leave channel 1 either completely dry or add just a touch of room reverb, and leave the cosmic stuff for channel two. That usually comes from pedals such as a Roland RE-202 Space Echo or UAFX Galaxy ’74. Both emulate the classic Roland Space Echo, and I love these stompbox versions because you can hold down a pedal for performance effects such as whooshing, blast-off kind of sound at any moment.

BLEND IN WITH VOLUME PEDALS

Once you’ve picked the pedals for each signal path, it’s all about getting a great blend. It's a good idea to start each signal chain with a volume pedal and end the pedalboard portion with a muteable tuner. Passive magnetic sound-hole pickups don’t have volume controls. Active ones do, but they can be difficult to access on the fly. Flywheel-style piezo controls in the lip of the sound hole are pretty good, but not as groovy as having a gas pedal at your foot. Having a pair of them is especially handy if you gig with more than one acoustic and need to balance volumes on the fly.

No matter how well you get your basic levels set at home, it’s always going to be a bit different on the gig. When you have a pair of volume pedals controlling the levels of a basic acoustic signal from your piezo pickup, and another at the ready for blending in some funky wah or spacey echoes, you not only have the best of both worlds at your fingertips — you’ve got a world of wonder at your feet.

In case you're wondering if you can feed the magnetic signal chain into an electric amp, the answer is a resounding yes. Can you leave the electric amp at home in favor of using a simulator pedal to totally transform your acoustic amp? Hell yeah! You can use tube amp emulator pedals such as the latest UAFX gems to turn your acoustic amp into everything from a shimmering Fender sound-alike to smoldering Dumble clone or even a fire-breathing Marshall. We’ll do a deep dive on turning your acoustic amp into an electric amp via emulation pedals in the next column.