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Sonuus G2M MIDI Converter Review

September 21, 2010

Download Example 1
Chords created by extending the release time on the synth
Download Example 2
Audio chord placed in Sampler, modified and triggered with guitar through G2M
Download Example 3
Solo over arpeggiated synth and drums. All sounds except distorted guitar generated using the G2M
Given how cutting-edge guitar synthesizers seem today, it’s hard to believe that they have been around for more than three decades. And, not surprisingly, they’ve evolved significantly in that time. The early-’70s models used by Pat Metheny and Bill Frisell were not equipped with MIDI and were only able to control certain dedicated sound modules. Because there were no MIDI-conversion latency issues, these guitar synths were able to track very well. Once audio-to-MIDI conversion became available, guitars equipped with hexaphonic pickups (that is, pickups that can send and receive audio separately from each of the six strings) could be used to control keyboard synthesizers, synth modules, and even samplers. Suddenly guitarists had the ability to trigger everything from synth pads and drum sounds to loops, string parts, and piano sounds.

If this all sounds like a history lesson in a foreign language, you’re on your way to understanding why guitar synthesis has yet to catch on in a big way. In the past, most guitarists’ eyes would glaze over when talk shifted to MIDI and synthesizers. And those who were interested were often put off by slow MIDI tracking, false note triggering, and the inability of early audio-to-MIDI converters to follow techniques like hammer-ons, pull-offs, slurs, bends, and tapping.

The Sonuus G2M, a MIDI interface that’s easy to use and eliminates the need for special jacks and pickups, has the potential to change all of that.

The Magic of MIDI
For those unfamiliar with the term, MIDI (musical instrument digital interface) is a digital message protocol designed to transmit musical events—such as, say, a pitch bend— to ones and zeros so that they can be processed by a computer. Companies like Roland and Terratec (Axon) have advanced audio-to-MIDI conversion significantly and addressed many early hurdles. But even the best MIDI converter still requires accurate playing at a level beyond some guitarists. To get acceptable results, you must pick every note cleanly and with exactly the right pressure. If you hit adjacent strings or allow notes to ring over each other, the MIDI module creates glitches and unwanted sounds. Sloppiness that’s perfectly acceptable—or even desirable—in normal guitar playing is verboten with a MIDI guitar.

This is one reason you are still unlikely to spy a 13-pin MIDI connector plug coming out of a guitarist’s hex-pickup instrument in a live performance (precision players like Pat Metheny and John McLaughlin aside). But the boom in home recording means more and more players are using an audio-to-MIDI converter in their studios, where less-than-perfect technique is not as much of an issue.

I have a Graph Tech Ghost hexaphonic pickup system in one of my instruments and have used Roland and Axon converters that both perform admirably despite my own technical limitations. Still, I often find myself reluctant to deal with the complexity of this technology. That learning curve, combined with my infrequent synthesizer needs, usually leads me to fall back on my meager keyboard skills.

Mini MIDI
The Sonuus could lead many users back to the synth guitar technology just by virtue of how easy it is to use. The G2M’s solid plastic case is smaller than an iPhone, though somewhat thicker. And basic operation couldn’t be simpler: Plug any electric guitar into one end and a MIDI cable into the other, then jack into your chosen MIDI device and go—no hexaphonic pickup is required.

A green power light indicates the onboard 9-volt battery is supplying juice. The power light also functions as a tuner, blinking more slowly as you approach the correct note. You’ll need to start with the string fairly close to pitch, but tuning is very accurate. And it’s a welcome addition given how essential correct pitch is for accurate tracking.

A red LED lets you know when battery power is getting low, and another red Clip light tells you if the instrument signal is too hot, which can also adversely affect accurate tracking. A Boost switch next to the 1/4" instrument input supplies extra power to low-output pickups, and a 1/4" Thru output sends your instrument’s audio signal wherever you choose (for instance, to an amp or mixer). The G2M also supplies 5-volt power to MIDI devices that require it.



Hands On
I plugged a Fender Stratocaster into the Sonuus unit and tested it by running a MIDI cable out of the device and alternating between two interfaces—an M-Audio Firewire 1814 interface and an M-Audio USB Midisport Uno—that sent a MIDI channel into Ableton Live software on my Mac. The Uno is a MIDI-only interface, but the 1814 allowed me to run audio into a separate channel in Ableton Live, which instantly recognized the incoming MIDI data. With the flow of data intact, I tried the converter with various software synthesizer plug-ins, and everything was easier from the very beginning with the Sonuus.

For starters, the G2M has a unique way of dealing with audio input level. In interfaces that require a hexaphonic pickup, the instrument’s overall output is determined by the pickup’s distance from the strings. Each of the six separate string levels is then controlled within the converter. It is much simpler with the G2M. I started with my guitar volume full up and the G2M’s boost switch off. Finding that the tracking was not as accurate as I’d hoped, I turned on the boost. The clip LED then started coming on more than it should, so I backed off the guitar volume a bit. Once the light only flashed occasionally— as recommended in the G2M’s delightfully brief manual—the unit achieved a level equal to, or better than, any converter I have tried with a few simple adjustments.

Sliding into notes was still sometimes problematic, but vibrato and half- or whole-step bends worked well. Even slight whammy-bar dips tracked accurately, giving me more of the expressive power we’re accustomed to as guitarists. As with any converter, I found that tracking varied greatly by synthesizer plugin— and there was still the typical variation between patches within each plug-in. But the G2M certainly gives you an advantage and flexibility in coping with those variables.

Will the G2M track lightning-fast shredder solos? That depends largely on how cleanly you play. Being monophonic, the Sonuus unit will sound glitchy if any note rings into another note. Rather than thinking of this as a flaw, you could simply practice picking more accurately (which can only be a good thing). And if you record the MIDI signal you’re sending, you can easily go into that track and fix any bum notes or bad timing, as well as erase any falsely triggered notes. One of the joys of MIDI, of course, is that you can also replace the original sound with any other MIDI instrument you choose.

I got around Sonuus’ other monophonic limitations in some interesting ways. Lengthening the release time of the synthesizer patch caused the first note I played to keep going while I played the second, and so on, allowing me to stack chord tones. Many synths let me tune their multiple oscillators to different notes, thereby also creating chords.

Here’s another trick: I recorded an audio Gmaj7 guitar chord and loaded its file into a sampler. I was then able to trigger it via MIDI with a single guitar note and change the chord’s key as I played different notes. Why not just play the different chords? Because once the chord was loaded in the sampler, I could manipulate the guitar sound in ways that audio effects can’t (check out the audio clip on the web).

Placing Live’s Arpeggiator plug-in in front of various software synths, I was able to turn one note into a rhythmic flurry of notes. Using the Arpeggiatior’s hold function, I could keep rhythmic parts playing while I soloed over them. I enjoyed the fact that the G2M let me solo with a synth tone blended with a distorted guitar sound. This technique disguised any latency in the synth tracking, and it also hid the occasional mistakenly tracked note.

The Verdict

MIDI offers guitarists used to—and perhaps bored of—the standard guitar-pedal-amp setup a wealth of new sounds. And with the Sonuus G2M, you can get into the action and start laying down drum parts, bass lines, arpeggiated dance or prog-rock parts, string lines, and more right away—and for half the price of a hexaphonic pickup! (You can even use it with transcription software to print solos or lines for students or publication.) Guitarists looking for polyphonic operation and the ability to switch synth patches from the guitar will want to stick with a Roland GK-2A or Ghost hexaphonic system with a Roland, Axon, or another polyphonic converter. But for those with more limited needs, or anyone who wants an easy way to start exploring the world of MIDI guitar, the Sonuus G2M is just the ticket.

Buy if...
you want a simple way to convert a mono guitar signal into MIDI for recording, performance, or notation.
Skip if...
you need massive MIDI control and polyphony.
Rating...


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