Monday, August 24, 2009

Gear Review: Sonuus G2M - Universal Guitar to MIDI Converter


The world of digital audio is really split into two different types of signals, and it can be hard to get a handle on it for the novice home recorder. The first, audio samples, is the easiest to understand. You record something, and it is stored in a format that sounds like what was put into it, like vocals, guitar, etc. The second type is MIDI. It can be confusing, because the term MIDI is used for both the interface and the data that describes what should be played. You really don't have a lot of crossover between the two worlds, since one is the sound, the other describes how to make the sound.

The one type of crossover that we have seen in recent years is the MIDI guitar. You play it like a guitar, but it sends out MIDI signals. These signals can then be used to control something totally different - a synth, a sample player, a piano, etc. These are very cool and full of possibilities, but they are expensive and usually require a special guitar or permanent modifications to your guitar. It seems like the cool toys are out of reach for the low-cost or frugal home studio.

Enter the Sonuus G2M. Billed as a "Universal Guitar-to-MIDI Converter" and retailing for around $100, the G2M aims to fill that gap in the affordable hardware department. I had the opportunity to spend a few weeks experimenting with the G2M, and I will be sharing my experience here.

Descriptions First...
The G2M is a pretty simple box with a 1/4" Input Jack, 1/4" Thru Jack (for direct routing to your normal signal path), and a standard 5 Pin MIDI Out Jack. There is also a "Boost" switch that amplifies the signal within the G2M, in case your input level is a little low. The "Clip" LED shows when you are clipping the signal (not a bad thing in this case), which you should run your signal so you occasionally clip so you know the G2M is getting a hot enough signal to interpret correctly. However, not having a needle gauge or digital readout of the level, this is only a ballpark accuracy measure for the overall signal strength. There is also a strobe tuner function built into the power light. The slower the light flashes, the closer you are to a standard note tuning. Nice, but that's not the primary purpose of this box. The unit is powered by a 9V battery only. There is no wall wart power supply option, but this isn't a major issue since the battery life is boasted to be about 70 hours. I have played with the G2M a lot, and still haven't run my 9V down, so I tend to believe their claims in that respect.

What Are The Specs?
Note Detection Range: E2 to E6
MIDI Latency: 16 ms to 30 ms (depending on note and characteristics of input signal)

How Do You Use It?
This is possibly the simplest box to get running. Insert a 9 Volt battery, plug a guitar to the input, a MIDI cable in the output leading to a MIDI Interface, and you're in business. Set up something to respond to the MIDI signal on the other end, whether a MIDI keyboard that accepts a MIDI In, or to your DAW, with a VST plugged in and "listening". Play your guitar, and see what happens.

Does It Really Work?
Yes, it really works. I've experimented with a few instruments, and the claims are true, to a point. What's important to remember is there are a few caveats that Sonuus is very up front with making clear. First and foremost, this is MONOPHONIC ONLY. Any attempt to play chords or multiple notes at the same time will scramble the signal and confuse the G2M. This is the one major concession made by having this box sit after the guitar. Since the signal from the guitar is a blended tone of all notes currently sounding, it becomes muddled in the line, and the G2M can't separate it out. Secondly, it works best with MIDI patches/VSTS with a pitch-bend range of + or - 2 semitones. Anything more sensitive is prone to a wobble to the sound. Thirdly, playing in a higher octave will result in better tracking of your notes. Since higher octaves are thinner, sharper tones, they are interpreted more accurately than lower bass tones.

My Guitar Experiences
I was off to a bad start when I first started using the G2M. It is a good idea to read the Sonuus G2M Guide available at http://www.sonuus.com/g2m_guide.html. In the Tips & Tricks section, it explicitly identifies piano sounds as sounding strange with a warble. Not having read that yet, I started with a piano patch. It resulted in tones that we used to describe as "alien" sounds. However, once I switched to a different VST to play through, it worked great. I really enjoyed the experience of playing live through the Prophanity (currently without a web site) and Oddy-Free synths. These are both modeled after classic modular synths (the Prophet V and ARP Odyssey Mk. II). Both of these synths had amazing responses and a really nice "feel" to the sound when triggered by the G2M.

Now I must admit, I have had some difficulties with the G2M, but they have mostly been my fault as a player. I'm a rather sloppy guitarist, with a lot of excess noise coming off the other strings. The G2M picks up the additional sloppy hits, completely misunderstands them, and I get strange high notes popping into the stream, usually about 2 octaves above what I'm playing. Some palm muting at all times helps, but being a clean guitarist helps even more. I feel like I'm becoming a cleaner guitarist the more I play through the G2M.

I have also had issues with the too-accurate capturing of the notes. It tracks so well, that slight warbles in the notes are translated as pitch bend parameters that are transmitted in the MIDI path. It is this accurate detection of pitch bending that causes piano VSTs to freak out. If you really want piano, you can remove the pitch change information from the recorded MIDI. (In Reaper, you can do this in the Piano Roll. Change the bottom "levels" frame to show "Pitch". If you hold down your right mouse button and wipe across these Pitch levels, it will erase them all, and the sound will clean right up). This doesn't help live situations, but for recording, it will work.

I'm always skeptical when a piece of budget hardware claims to have a low latency, as the G2M does, with the stated 16 ms to 30 ms. I don't have an accurate bench test in my gear to determine the actual latency, except for audible comparison. I have to say that it performs similarly to both POD Farm and Guitar Rig 3, which clock in around the 30 ms total signal time. The latency is low enough that it isn't really noticeable. Of course, there is also the fact that I can't play fast & clean at the same time, so it's possible I'm not pushing the speed threshold where latency might throw you off (i.e. in speed metal shredding).

Alternate Controls
When I first heard about the G2M, my first though went to the "undocumented" options. It takes an audio input. What about other audio sources?

I have tried a Bass guitar, and it is a bad idea. Since the G2M responds best at higher pitches, the bass is mostly out of range. In my testing, I couldn't play a note lower than D on the second string of the bass. Strings 3 and 4 were completely invisible to the G2M. And what I could play was tracked very badly, with a lot of extra blips where it tried to read the harmonics as the note. Worth a try, but not worth using.

The best alternate success I have had was with a microphone. Using a moderately cheap 1/4" mic plugged through to Prophanity and Oddy-Free (in REAPER), the result was delightful. It reminded me of playing with a vocoder with the original voice 100% consumed by the rest of the sound. I also found it to be really fun to control the Delay Lama with the microphone to G2M path. For the most part, though, the more precise the sound from the VST (where all notes really sound distinct - like bells, piano, etc) the worse the performance when using a microphone. I think the human voice has so many pitch variations that it becomes a little too dynamic for the G2M.

My G2M Wish List
A few things I would have liked to see on the G2M:
* Controllable Sensitivity Range (to help sloppy players!)
* Polyphonic ability (Melodyne developed a system that can break apart chords into component notes, so it is technically possible)
* Variable boost control
* External power pack option

Final Thoughts
I really like the G2M and the possibilities it opens up for the home studio. There are definitely limitations and some performance considerations that must be made in a trial and error method (like which VSTs sound good with it), but I still think this is worth the $129 retail price for this little box. I have been listening to more experimental music lately, and this could easily find its way into the toolkit of any glitch, noise, or aggressive electronica project, especially when used as a sidekick process to a vocoder, since you can get really wild effects when you push the G2M to its limits (and beyond).

When used according to the instructions, this can be a nice tool for a guitarist if they play fairly cleanly and monophonic. I think the monophony is the greatest limitation. If you can work with that one concession, this box performs exactly as their claims. As this is the first product from Sonuus (a U.K. based company), I am eager to see what they come up with next.

Disclosure
In the interest of full disclosure, I was provided a review unit by Peterson Tuners, the exclusive distributor of the Sonuus G2M in the United States and Canada. This was a loaned unit only - I had to give it back. There have been no incentives, financial or otherwise, provided to me for this review. (i.e. I didn't get a thing from them except the opportunity to play with this gear)

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