Review: Audio Sprockets ToneDexter Acoustic Preamp

For years I refused to put a pick-up on my fiddle and would only use a microphone onstage. I was such a hardliner about this that I would turn down any gig where plugging in was required.

Because let’s face it, the direct signal from a fiddle bridge pick-up sounds pretty bad. It takes a direct-box with a lot of EQ capability — like the LR Baggs Para DI or the Grace Designs Alix — to make most pick-ups sound just okay. Barely.

So you spend years and years working on your technique and finding just the right instrument so you can produce the sound you hear in your head. And then you plug your fiddle into the PA only to hear that pinched, nasal, mosquito-y tone coming back at you. It’s like taking the best meal you’ve ever eaten, putting it in a blender, pouring it in a glass and chugging it. How depressing!

But in the last few years, a crop of IR (Impluse Response) pedals and DIs have come on the market, and many acoustic musicians have been using them onstage and raving about them.

In broad strokes, IR pedals “learn” the sound of your instrument when it’s mic’d, and then apply that sound digitally on top of the direct signal from your pick-up. For a more technical explanation of how this technology works, I’ll refer you to Google.

Almost two years ago, I decided to give the Audio Sprockets ToneDexter acoustic preamp a try. Plugging in would certainly make live sound easier. “Ringing out” a condenser mic — EQing out the frequencies that cause a mic to feed back — is a pretty high-level skill that a lot of sound people, especially those who are used to mixing rock bands, don’t seem to have (or have the patience for) these days.

Since then, I’ve used the ToneDexter live with The High 48s and Becky Schlegel, usually in conjunction with an Audio Technica large-diaphragm condenser mic.

I use the signal from the ToneDexter almost exclusively in the monitors, since it’s very feedback resistant. And then the front-of-house person mixes the signal from the ToneDexter with the signal from Audio Technica condenser mic.

Since I’ve switched to this hybrid mics-plus-DI setup, my sound has been dead consistent from gig to gig. Getting enough volume onstage without feedback isn’t a problem. And the best part is that the sound I’m getting, even when I use the direct signal from ToneDexter on its own, is big and natural sounding.


The ToneDexter sounds pretty darn good. I wouldn’t use the ToneDexter to record in the studio (it doesn’t sound quite that good), but onstage, I don’t wince at what I hear coming out of the monitors.

I know that sounds like faint praise, but it’s not. If you’re in a situation where plugging is the only option — i.e., on louder stages — pretty good sound is something close to miraculous. Even with the best direct box and the most advanced EQ, you won’t get tone this natural sounding. Not even close.

And if you pair the ToneDexter with an EQ pedal (I use the LR Baggs Align Series EQ), in a live setting your tone will be virtually indistinguishable from what you’d hear through a microphone. Since I’ve started using the ToneDexter, I’ve had several people ask me after gigs what kind of clip-on mic I’m using. I think that’s saying a lot about the quality of sound the ToneDexter delivers.

I should also mention Audio Sprockets’ customer service. When I first started training the ToneDexter, I emailed the company about a problem I was having (which was 100% user error). James May, one of the engineers who designed the ToneDexter, responded promptly with very helpful information.


This pedal will eat up hours of your time. Getting the best sound of the ToneDexter takes a while. I’ve used several different mics to “train” my ToneDexter (there’s a very good tutorial on that subject here) and have been continually tweaking my Wavemaps (the processed sound coming out of the ToneDexter) since day one. And it still feels like a work in progress.

To be fair, the ToneDexter’s tweak-ability is a feature, not a bug, and for some users that’ll be a pro, not a con. But if you’re looking for something that’s basically plug-and-play, this may not be the best option for you. This pedal requires — and rewards — some patient experimentation.

Another thing I don’t love about the ToneDexter — and granted, this may be down to how I’ve trained it — is that it seems to produce a kind of high-frequency, digital-sounding noise somewhere up above 10k. To my ear, it almost sounds like a badly simulated small-room sound on a digital reverb. A little harsh and weird sounding. This is especially noticeable as the processed signal (as opposed to the straight pick-up signal) approaches 100 percent.

This is where the LR Baggs EQ comes in handy. Running it out of the ToneDexter’s effects loop (thank you Audio Sprockets for putting in an effects loop!), I use the EQ to filter out the harshness in the >10k range. That does the trick. In my video demo, though, you’ll be hearing the un-EQ’d signal, straight from the box.

The other thing I don’t love about the ToneDexter is its visual design. All of the knobs are labeled with white text on a red background. Put this color scheme under stage lighting and you can’t read a thing. (The ToneDexter isn’t the only offender on this count; see the Chase Bliss Mood pedal, with its white text on a peach background…good luck with that!). Everyone I know who uses the ToneDexter has, like me, bits of tape stuck to it to label the controls.

About the ToneDexter Fiddle Demo.

In this video I reference the ToneDexter against the excellent Bartlett Fiddle Mic, a clip-on style mini-condenser mic that’s voiced for fiddle. Note that this is an especially warm sounding mic, which sounds great in a live setting. Here, since there’s no EQ or low cut, it comes across a little woolier sounding than it might when I use it out in the wild.

Also note that I’m not using any EQ on the ToneDexter either — what you hear is the ToneDexter straight up. Onstage I use the LR Baggs EQ to roll off the treble above 10k and warm up the fundamental with a boost around 350-700hz.

Finally, it’s worth noting that when I use the ToneDexter live, I generally use a 50/50 mix of the pickup signal and the processed signal (this balance is easily adjustable on the pedal) from the ToneDexter’s Wavemap. In a live setting, I find that’s what tends to sound best. In comparing notes with other ToneDexter users, it’s often the case that what sounds good in the practice room is often very different from what sounds good live in a band context. So when it comes to the wet/dry signal ratio, season to taste.

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