Reviews

In Review: ToneDexter Acoustic Stringed Instrument Preamp/DI

A closer look at a new tool from Audio Sprockets that brings studio sound quality to acoustic instruments on the live stage.

On The Road

Matt Fitzgerald ran monitors for Peter Frampton’s recent Raw: An Acoustic Tour, where all of his acoustic guitars were run through the ToneDexter, using instrument-specific presets that were created mainly before the tour began.

For previous tours, a Neumann KM 184 was used to supplement the sound of his guitars – equipped with LR Baggs pickups, and run through an Avalon U5 Tube DI.

For this tour, the signal was split between the Avalon DI and the ToneDexter, with the resulting two signals blended at FOH in differing proportions, depending on the song.

Guitar tech Aiden Mullen describes the signal path: “We jump off the Avalon’s link out/thru via 1/4-inch cable and go straight to the ToneDexter, sending both XLR DI output and ToneDexter separately to monitors and FOH.”

Each instrument was “trained” before the tour with the results stored as presets. Mullen adds, “We tried different combinations of rooms, mics, and outboard preamps for every guitar he takes on the road. Every guitar has its own specific character, and we found the ‘sweet spot’ for each one. We have 16 presets in the ToneDexter, and some of the microphones we used are the KM 184, KM 88, U67, DPA 4011, and Sennheiser 451.”

Peter Frampton’s guitar rig.

In some cases such as the 12-string acoustic, a couple different presets – based on different mics or mic positions – were used during the performance. Talking about how the character of the sound is captured, Fitzgerald comments that “Peter laughs and says ‘it feels like I’m sitting in my studio’ because the characteristics of the microphone and room where it was recorded are present.” During the shows, the ToneDexter was located offstage near Mullen, who selected the setting corresponding to each instrument before handing it to Frampton.

Discussing the benefits that this new addition made to their live show, Fitzgerald says, “Blending an acoustic instrument microphone to any kind of good level always made for a phasing challenge along with open vocal, audience, and other mics. Ruling that microphone out, and still having a microphone sound, is unbelievable. To me this is kind of a magic box. It’s is a steal, for what it does.” Mullen concurs, noting, “For our live shows we need 100 percent consistency, and that’s what we get.”

John Jorgenson has tried about every pickup and preamp solution in his long career playing guitar, mandolin, and other stringed instruments with the Desert Rose Band and the Hellecasters, as well as gypsy jazz, bluegrass, and numerous stage and studio collaborations with top artists.

Though some of them worked all right, he always thought that “somebody should figure out how to look at what a piezo pickup does and what a microphone does, see the difference, and make a system that sounds like a mic on a guitar. I was skeptical when I first heard about it as a beta version, but when I got a chance to try the ToneDexter, I was blown away because it does exactly what it’s supposed to do.”

Jorgenson said that his best solution for an acoustic sound previous to using ToneDexter was a mic mounted on the instrument, but that the new system gives him more flexibility for his instruments playing live.

Read More
dBTechnologies VIO Supports Rototom Sunsplash Festival In Spain

His 6-string uses an LR Baggs Anthem pickup, and the Takamine 12-string has a stock under-saddle piezo, and he used one of his studio condensers for training the system.

John Jorgenson performs live with ToneDexter

To create the presets for the gypsy jazz guitar and mandolin and their piezo pickup systems, he used Ear Trumpet’s Edwina large-diaphragm condenser. Since he began using the ToneDexter, he says that “it has made it 100 times easier for the monitor and FOH engineers to get a good sound.”

He still needs to add a volume pedal going into the unit, because with the gypsy jazz and bluegrass combos he can no longer back off the mic to comp chords when not soloing. Jorgenson adds, “I’ve never been happy playing mandolin on a big stage, but with this system it works amazingly – dynamics, tone, you don’t have to change your right hand technique – you can play like you want to play.”

Jeff Ross is an LA-based gypsy jazz player – along with blues, rockabilly, and other styles, using the traditional Selmer Maccaferi guitar and also a la’ud (similar to a small oud, both using Big Tone or similar bridge-mounted piezo pickup systems) in ensembles such as the Hot Club of LA and Gypsy Groove.

He says that the fight has always been between getting sufficient level by sacrificing the tonality of the guitar, or using a mic and not being able to compete with the other louder instruments on stage.

Ross notes that “people think that the harsh piezo sound can be dealt with in the EQ, but it’s not in the EQ – even shaping the highs and upper mids, I can still hear that harsh, picky sound but it sounds like there’s a blanket over it.”

“With the ToneDexter,” he adds, “I can get the headroom without worrying about feeding back, and I can get a nice acoustic guitar sound.”

Ross approached creating presets for the ToneDexter a bit differently, going to two different studios and using several different high-end Maccaferi guitars – the same basic model as his guitar with the same pickup system, and Neumann condenser mics to create a variety of WaveMaps to use with his performing instrument. During sound check, he selects which preset sounds best in the room with the sound system.

Firmware & Other Details

The latest firmware upgrades for the ToneDexter preamp/DI offer three different versions: for guitar and similarly pitched instruments; acoustic and upright basses; and treble instruments such as mandolin, violin, or ukulele. The versions provide different frequency ranges for the notch filter and equalizer, and a longer sampling for the bass WaveMap. For example, the bass notch filter ranges between 37 and 165 Hz.

The same unit can be updated with any of these versions, but will only hold one at a time. So a sound company could keep ToneDexter systems in their touring inventory, customize them before the tour for the basic instrument type, and then train them to the particular instruments during pre-production or before the gig while on the road.

All in all, from my experience with the ToneDexter acoustic instrument preamp/DI and from the touring professionals who have used it in concert, the system is a potential game-changer for the live reproduction of acoustic stringed instruments. The sound can be customized to the specific qualities of the instrument and pickup system, yielding the characteristics of a miked acoustic with the flexibility and greater SPL before feedback of a pickup.

Read More
Inside Audio Filtering Part 2: More Fundamental FIR Filter Concepts & Applications In Loudspeakers

Find out more about ToneDexter at the Audio Sprockets website. Units can also be purchased ($399) via the site.