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SON-GM2  RRP $159


G2M - Guitar to MIDI Converter - by Sonuus


So what is the G2M™?

The G2M™ is a utility box that converts an electric guitar signal to a stream of MIDI messages; all in real time with low-latency. But what exactly does it do and why do you need one?

An electric guitar has magnetic pickups which convert the movement of the vibrating strings into an electrical signal. This signal is the "analogue" of the guitar string's vibrations. When connected to a guitar amplifier these signals produce the sound with which we are all familiar.

MIDI, on the other hand, is a purely digital message protocol that tries to accurately describe a musical performance in terms of note-on, note-off, pitch-bend and other similar messages. These messages are then used by a sound module to generate realistic-sounding performances. The realism that can be achieved is quite incredible. However, this realism relies not only on the quality of the sound module, but also on the accuracy and finesse of the raw MIDI messages.

For more information on MIDI, click here.

For many instruments, a standard MIDI keyboard can be used to create the required MIDI performance. But to get believable results for some instruments requires specialised controllers. For example, there are dedicated controllers available for drums, wind instruments and guitars. There are two advantages to dedicated controllers: firstly, by having a familiar tactile interface, the musician can perform naturally; secondly, many musicians only have basic keyboard skills and find it difficult (or impossible) to use a keyboard to get the nuances they desire.


G2M is not the same as MIDI Guitar 

A MIDI guitar is essentially a guitar that is capable of generating MIDI messages that accurately represent the performance being played. It presents a familiar interface to guitarists (i.e., it is a guitar!) and is played (usually) exactly like any other guitar. There are two popular variations of MIDI guitar: those with MIDI capability installed during manufacture; and those with the necessary equipment added by the end-user. This equipment is usually a "hex-pickup" which is a standard guitar pickup that has been split into six parts to isolate the signals from individual strings. The signals from the hex-pickup then have to be decoded by an external unit which converts the electrical signals into MIDI messages.

G2M is does not do Polyphonic MIDI

The main advantage of a MIDI guitar with a hex-pickup is that signals from all the strings can be converted simultaneously and chords, double-stops and other multi-string events can be handled (i.e. it is polyphonic).

But there are also several disadvantages: factory-fitted MIDI guitars are expensive; hex-pickups can be difficult to set up for reliable operation; external units can be cumbersome and power-hungry.

G2M does do Solo MIDI

In many cases, you only need to convert solo guitar to MIDI. For example, to sequence bass-lines, record melodies, simulate orchestral strings, and of course for the classic guitar solo.

While the aforementioned MIDI guitars can be used successfully for solo guitar, their additional expense and fiddly setup often mean it is a hill too steep to climb for many musicians. The ideal solution would be a MIDI guitar tailored for solo performances without any of these disadvantages; this is the G2M™.

The ideal solution would be a MIDI guitar tailored for solo performances without any of these disadvantages; this is the G2M™

Benefits of the G2M™

Costing much less than a hex-pickup, and a fraction of the cost of a polyphonic MIDI guitar system, the G2M™ connects directly to any electric guitar to instantly give it MIDI capability. Indeed, the G2M™ costs less than many basic guitar tuners! Whether you have the cheapest beginner guitar or the finest Les Paul, the G2M™ will work for you.

Setting up to use the G2M™


  • Simply connect your guitar to the G2M™ (the GUITAR input) using a standard guitar lead and the G2M™ will turn on (if it doesn't, check the battery!).
  • Next, connect your sound module, computer or other MIDI device using a standard MIDI cable to the G2M™ (via MIDI OUT).
  • (Optionally) if you want to listen to, or record, the raw guitar sound, connect the THRU to your guitar amplifier or other recording device.

Ensure your instrument’s level is optimally matched to the G2M™ by adjusting its volume control to give a signal which only occasionally causes the clip LED to light. Occasional clipping will not cause any performance problems and a high signal level ensures that sounding notes will sustain for as long as possible. However, you should avoid having the clip LED flashing most of the time. For guitars with a low output level from the pickups, the G2M™ may have problems tracking the signal. In order to compensate for this, the G2M™ has a BOOST switch which increases the gain of the guitar signal into the MIDI converter. Note that BOOST does not affect the level of the THRU.


On the G2M™ the power LED also functions as a neat guitar tuner which enables you to ensure your guitar is at the perfect pitch for the performance. As the G2M™is highly compact and portable you don't need to carry a separate tuner with you in your guitar case.  The tuner will automatically recognize the notes of a standard guitar tuning (EADGBE). Simply play an open string such as bottom 'E' and the tuning LED will pulse to indicate how closely in-tune you are. The slower the LED pulses, the closer you are. Once the LED has stopped pulsing (whether on, off or in-between) then you're perfectly in tune. Repeat this process across all the strings of the guitar and your tuning will be spot-on and you're ready to play.

Pitch-bend settings

As you bend a string whilst playing with the G2M™ it will output MIDI pitch bend messages. The G2M™ is configured so that the full range of pitch bend corresponds to -2 to +2 semitones. This is the widely accepted standard range to use, but some sound modules may use other ranges, and indeed many can have their range adjusted. It is important that the sound module you use is set to match this -2 to +2 semitone range. If you find the sound module seems to be out of tune, it is sensible to first check the pitch-bend settings before exploring other possibilities.

Tricks and Tips

The G2M™ operates at its best when it can clearly distinguish individual notes from the guitar. The following tips are provided to help you get the best performance from your G2M™.

Choose a good MIDI patch (sound)

Some sounds do not sound good when played by a MIDI guitar because they are not intended to be played with the subtle pitch-bend that the guitar produces. In particular, piano patches can sound strange and can appear to "warble" with small amounts of pitch bend. If you still want a piano sound, try turning off the pitch bend reception or try to play very carefully to minimise pitch bending notes.

For best results use patches that are well suited to control by guitar including synths, brass, wind, and of course guitar sounds.

Guitar Setup

It is important to ensure that your guitar is set up correctly to prevent  problems such as buzz when fretting notes which can cause spurious notes to be generated by the G2M™. This may mean adjusting the action of your guitar slightly to resolve the problem. If you are in any doubt how to set up your guitar we recommend that you consult a guitar technician at your local music store.

Plectrums (Picks) and pickups

A guitar signal often contains many harmonics. Harmonics are sound frequencies that are related to the individual note that is being played. Although the G2M™ handles this well, it can sometimes get confused if the harmonics are much larger than the bass (fundamental) tone. This is usually only a problem when striking new notes.  We have found that using the neck pickup rather than the bridge pickup generally gives less harmonics, and by using nylon plectrums instead of harder plastic or bone plectrums smaller harmonics are generated at note-on. Try these suggestions if you are having problems with the wrong note being briefly detected.

Improve your playing technique

For optimal MIDI conversion, your guitar playing needs to be clean and accurate. Accidental notes, resonating open strings and other sounds can often be converted into undesired MIDI notes. Often you don’t hear these when playing guitar yourself, but can detect them easily when listening live to the generated MIDI.

Striving to improve MIDI note accuracy, encourages clean picking and accurate fingering, with good control over non-sounding strings by damping them.

Not only will your MIDI output be more accurate, your normal guitar playing will sound clearer and more professional. It’s like having a tutor sitting beside you giving you advice. It’s also great fun!

Playing technique suggestions

Slightly mute strings with your picking hand. This helps prevent spurious MIDI notes when the wrong string is touched lightly during playing. It also improves the detection of picked notes because notes can decay slightly faster to give greater contrast between the new note and the last note.

When you stop a note, you should not release your finger from the string, instead just reduce the pressure on the string until it is no longer pressing on the fretboard. This will allow your finger to damp the string to avoid movement of the open string being detected.

If you find that the wrong note (or octave) is briefly detected when you play a note, try the following tips for your guitar:

  • Try using the neck pick-up.
  • Turn down the guitar's tone control to see if this makes a difference.
  • Slightly adjust your playing style or playing position. Often moving where you strike the string by a small amount can give good results.

Usage Ideas

Sequencing bass lines

The G2M™ is great for sequencing natural-sounding bass lines. It is often more convenient to play the bass line using the higher octaves on the guitar where tracking is most accurate and latency is lowest. The resulting recorded performance can then be transposed in your sequencer to use as a bass line. Many sequencers will allow transposition of any number of semitones. Then, for example, you can play on the 3rd string and transpose back to the 6th string or lower.

Enhancing live performances

Mixing your live guitar sound and a synthesizer sound generated via the G2M™ and your sound module or software synth provides a new dimension to your playing. Add to searing lead lines with a detuned synth lead, add rich harmonies using a transposed patch, get a huge wall of sound using bass sounds an octave down to follow your lead playing or rhythm picking.  Once your guitar signal is translated into the MIDI domain, there's no limit to the layering of sounds you can achieve.

Guitar Solos

Tricky-to-play fast guitar parts such as solos can be recorded into your sequencer at a slow speed so accuracy can be achieved in the performance. Any mistakes in the recorded MIDI can be edited out in the sequencer and the result can then be played back at the required speed by changing the sequencer tempo. And because it’s MIDI you don’t get any of the transposition artifacts you would get if you tried to do the same with the original audio! 

Notating your music

The G2M™ is a great input device when used togther with music notation software such as GuitarPro and Sibelius and most Digital Audio Workstation (DAW) software such as SONAR, Logic and Cubase. No longer do you have to think about how you will score your guitar part, you can simply connect via your G2M and play.



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