A guitar synthesizer (also guitar synth, alternatively guitar-synthesizer, guitar-synth, guitar/synthesizer, guitar/synth, g-synth or synth guitar) is any one of a number of musical instrument systems that allow a guitar player to play synthesizer sound.
Today's guitar-synthesizers are direct descendants of originals offered in the 1970s by early manufacturers such as Hammond Innovex & Ovation, EMS, Roland Corporation & FujiGen (GR-500 and GR-300), Ludwig, Norlin Music & Maestro, 360 Systems, Ampeg & Hagström, Arp, Electro-Harmonix. Other notable manufacturers include Casio,New England Digital, Terratec/Axon, Starr Labs, Ibanez, Holt Electro Acoustic Research, Zeta Systems, and Yamaha.
Later, multi-effects type evolved into modeling guitar, and the other two types evolved into current guitar-synthesizers.
Both types have advantages and disadvantages.
Though the term "MIDI guitar" is sometimes used as a synonym, MIDI is not the indispensable feature of guitar synthesizers, especially after advances in DSP technology. Software guitar synthesizers without any special pickups have appeared, featuring polyphonic audio recognition (recognizing polyphonic pitches of each string, and possibly distinguish combination of fret positions and strings).
Typical instruments in this category consist of:
This data can be stored or input directly to a synthesizer that generates corresponding notes that can be made audible when played through an amplifier and speaker.
These components may be integrated into the instrument body or modularized in different ways. The hexaphonic pickup may be a separate component added to the guitar, or it may be built-in. Earlier guitar-synths required the musician to use a proprietary guitar with an integrated hexaphonic pickup.
Roland developed its GK series of hexaphonic drivers, consisting of a divided pickup and associated electronics (essentially a buffer preamp for each string signal). These were used in two ways, either with pickup and buffer module mountable to the guitar, or as a "GK-KIT" intended to be fitted into a guitar body by a luthier or manufacturer.
The initial GK-1 had 24 output pins, with a resultantly bulky interface cable. The design evolved into a smaller 13-pin format, used in the Gk-2, GK-2A, and GK-3 pickups, as well as the GK-3B bass pickup.
Fender released their Fender VG Stratocaster, a Standard Series instrument with inbuilt GK-2A hexaphonic pickup kit. Fender had previously offered a short-lived American Series version in the mid-1990s.
Godin and a few other guitar manufacturers offer guitar models with an integrated "RMC hexaphonic pickup and preamp system" that is compatible with Roland devices. The RMC pickup system uses a piezo-crystal pickup device built into the saddles of the guitar bridge, which conduct the vibrations of the strings as a signal that can be converted into a (13-pin) hexaphonic synth signal. This setup can be found in the xtSA and the LGX models.
The GK drivers or compatible controllers are connected to a dedicated synthesizer module like Roland GR-1 or Roland GR-55 via a cable with 13-pin connectors. The module sits on the floor and has the appearance of a large effects unit, with footswitches for the selection of sounds and memory banks.
Usually, a cable connects the hexaphonic pickup to the converter. This allows the guitarist to be unencumbered by an on-board converter. However, several Casio models in the PG and MG product lines integrated the guitar, the hex pickup, and the converter as a single unit. Casio remains the only manufacturer to try this approach. The advantage of this arrangement is that a MIDI cable can be plugged directly into the guitar. Disadvantages include weight and the need for an external power supply.
In addition to these configurations, the converter may also be combined with a synthesizer. The earliest models were combination converter/synthesizers, and this type is still produced. As the early integrated models predated the MIDI standard, their components were not interchangeable; the guitarist's only option was to use whatever synthesizer came with the converter, and vice versa. By the 2000s (decade), however, all converter/synthesizers were MIDI-compatible, so any synthesizer with MIDI-input capability (the vast majority since the 1990s) can be used. Stand-alone converter units also drive synthesizers via MIDI.
Among the advantages of synth guitars are that the musician can play either the guitar or the synthesizer alone, or blend the timbres of the both together in any ratio. Many models can be used with almost any guitar, with the addition of a hexaphonic pickup. In the early systems, there was a detectable latency, especially at lower pitches, between playing a note on the guitar and the note's sounding on the synthesizer, but this was remedied in 2000s-era instruments. While this type is also somewhat prone to note-tracking glitches, the problem can be overcome by adjusting the sensitivity controls of the pickup or converter — and by playing more precisely. Another possible disadvantage is that not all of the variable performance parameters available on a synthesizer can be actuated from a guitar; a synth guitar lacks assignable controls to open a filter in real-time, for example. Nevertheless, contemporary synth-guitar designs often include an expression pedal for such purposes.
Some guitar-synthesizers consist with two separated parts, guitar controller and interface & sound module, where the former control the latter (as in Roland instruments). One of the challenges of using guitar-synthesizers is that not all guitar-playing techniques can be smoothly translated into MIDI and resulting sound. Harmonics, palm mutes, hammer-ons (in which the fretting hand strikes the string onto the fretboard), pull-offs, and pick slides are not easily picked up by guitar-synthesizers, usually due to sloppy fretting hand technique. With the exception of harmonics and palm mutes, these other techniques can be achieved with a concentrated effort to maintain good fretting technique. Similarly, synthesizer part of guitar-synth often lack the variety of controls (sliders, faders, and knobs) for synthesis parameters that are normally available on a standard keyboard synthesizer.
Nevertheless, controlling a synthesizer with a guitar has some advantages over a keyboard. More expansive chords are possible, and some intervals are easier to reach. As well, guitar-synthesizers provide access to sounds normally available only to keyboard players and percussionists. A guitar player could play a flute part using a sampled flute patch, or play percussion by triggering synth drum voices. As well, by blending the regular electric guitar tone with synthesized sounds, a guitarist can create a hybrid timbre. The guitar-synth also enables a guitarist with limited or no keyboard-playing skills to program a sequencer and do MIDI input into digital notation programs such as Sibelius and Finale.
Some manufacturers of guitar-synthesizers wanted to eliminate the tracking and latency problems associated with guitar-based systems, while retaining the expressiveness of the guitar. They achieved this, to some degree, by redesigning the instrument part of the human-machine interface so that it was better suited to driving a synthesizer.
The 1980s-era SynthAxe was a futuristic controller consisting of a fretboard attached to the body at an obtuse angle. The fretboard strings were used to indicate pitch and sensed string bends. A separate, shorter set of strings were used for picking and strumming. These triggered the notes fretted on the fretboard's strings. It also featured trigger keys that could be used instead of the trigger strings. A whammy bar was assignable to any MIDI parameter. The SynthAxe was prohibitively expensive and therefore not widely used. Two of the most famous SynthAxe users are guitarist Allan Holdsworth and percussionist Roy "Futureman" Wooten of the jazz quartet Béla Fleck and the Flecktones. Wooten programmed his modified SynthAxe controller with a variety of Drum Kit and Percussion sounds. The instrument was previously owned by jazz guitarist Lee Ritenour.
Yamaha originally entered the market with a guitar-like MIDI controller called the "G-10," considerably less expensive than the SynthAxe. The G-10 had two assignable knobs and an assignable whammy bar and it used six strings, all the same gauge [thickness], which sensed both right- and left-hand input. The fact that the strings were all of the same thickness made the instrument feel substantially different for a player, in contrast to the typical guitar, and may have hindered the instrument's acceptance.
Both the SynthAxe and Yamaha G-10 have been discontinued.
Beginning in the early 2000s, Yamaha have re-entered the market with simple midi guitars (EZ-AG and EZ-EG) these have illuminated frets to teach finger technique and 20 voices.
Starr Labs' Ztar is one of the few remaining guitar-like controller product lines still in production. A Ztar differs significantly from the SynthAxe and Yamaha G-10 in that the "fretboard" is covered with keys, not strings. Keys in the same row can trigger notes at the same time. This has no analog on a real guitar. It would be as if a single string were polyphonic. A number of variations are available, including an instrument that uses strings for strumming or picking, to trigger notes, whereas the pitch of the notes is determined by the keys that cover what would be a "fretboard" in an ordinary, stringed guitar. Starr labs recently introduced the Z5S, a simpler and less expensive version of the Z6S. MIDI guitar controllers have regained popularity due to the Z6 model, possibly because of its usage by Rob Swire of Pendulum, who uses it on songs where he is required to perform vocals.
The You Rock Guitar, introduced in 2010 by You Rock Digital, combines a MIDI guitar controller/recorder with a patented touch-sensitive fingerboard and an on-board synthesizer. The instrument supports not only strumming and picking, but also tapping and sliding techniques, and provides a whammy bar for pitch bending and a modulation. Control panel software gives users control over 40 parameters, including velocity tables, string sensitivity, and synthesizer presets. The You Rock Guitar is used by guitarists such as George Pajon Jr. (Fergie, The Black Eyed Peas) and Josh Kelley.
Rock Band 3 features three guitar controllers.
One is modeled after the Fender Mustang, with 6 string sensors stretching from the bridge to the location of the neck pickup of a standard guitar and 102 buttons in 6 columns of 17 frets, which together create MIDI note data. The other is being built with Fender and is a fully functional guitar, with a bridge pickup "listening" to the strings and sending MIDI information to the MIDI port. The Mustang model will retail at 150 USD.
"You Rock Guitar" is compatible with Guitar Hero and Rock Band 3, including RB 3 Pro Mode. It was named Innovation of the Year by USA Today in 2010. The guitar provides a number of features that help gamers to become guitarists. The You Rock Practice Mode provides audible feedback when the user plays with the guitar's built-in song loops. The guitar can simultaneously drive a game system, an amplifier, headphones, a MIDI synthesizer, and music software via USB. The street price is around $200.
The advantages of the guitar-like MIDI controller systems are that the tracking [the speed and accuracy of the notes the instrument produces] is much better than guitar-based systems, which means that there is no noticeable latency or pitch glitches. As well, whammy bars and other controllers can be assigned to any MIDI function, which gives the performer more on-stage control of their sound. Further, these controllers offer playing options, such as the keyboard-like tapping style, that are not possible on traditional guitars. Finally, the instruments with touch-sensitive fingerboards never need tuning, and they are easier on the fingers of beginning and casual players.
The disadvantages for guitar players are that the controller is not exactly a guitar, and the feel is different. Some instruments are rare and expensive, which may make it difficult to repair or service them.
A number of well-known guitarists have used guitar synthesizers, often working in the jazz or progressive rock genres, or soundtrack composition; these include Jimmy Page, John McLaughlin, Chuck Hammer, Pat Metheny, Steve Hackett, Brian Hughes, Russ Freeman, Andy Summers, Allan Holdsworth, Matt Bellamy, Roger Troutman, Bootsy Collins, Robert Fripp, Vernon Reid, Mike Oldfield, Bill Frisell, Trey Azagthoth, Amir Derakh, Les Fradkin, Mike Stern, Adrian Belew, Joni Mitchell, Jeff Baxter, Eric Clapton, Yannis Spathas, Rob Swire, Dave Murray, Adrian Smith.