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Sound-On-Sound: Roland GR-Series

Originally published August, 1999

Recognising that there are millions of synth-hungry guitarists out there, manufacturers have been trying for years to develop products which would appeal to them. Norm Leete traces the history of Roland's innovative GR range of guitar synths and controllers.

Roland GR-500Back in 1980 one of the more expensive studio holy grails was the polyphonic synthesizer. I remember drooling over the SCI Prophet V and Yamaha CS80, and being unable to afford one -- so an alternative to lengthy sessions overdubbing single notes from my band's Minimoog had to be found. My answer was to get hold of a guitar synth!

Several manufacturers have had a go at the problem of designing these instruments, but only Roland seem to have refused to give up on the idea (stubborn or what?). Others who have dabbled, with varying degrees of success, include Casio, Yamaha, Stepp, Hagstrom, Synthaxe, 360 Systems and ARP.

In this article I will only describe the earlier versions of the Roland Guitar Synth systems that have a dedicated guitar controller as part of the setup. I actually prefer the idea of a dedicated guitar (but then I am a bit weird!), and the guitars themselves are pretty good. Roland seemingly didn't like the idea of making guitars, for as soon as they had managed to shrink the relevant guitar synth electronics to a size that could be attached to any guitar, they stopped supplying the guitars. The logic is reasonable, as it means that you can now simply convert any existing guitar to be a synth as well, which fits with the way most people want to work. Once Roland no longer produced dedicated guitar controllers, the synthesizers became familiar 19-inch racks with a voice architecture similar to the 'D' series synths. After a few more floor-mounted efforts, the synth section was dropped as well, and their current system is a guitar-to-MIDI converter.

In The Beginning... The GR500

Divided Attention

The principal technical challenge in designing a synth guitar controller lies in making a pickup that can accurately convert the vibration of the strings into the sort of information that can drive a synthesizer. Most guitar synth systems work using a divided pickup (there have been systems based on other technologies, but these have not been popular or as common). This is a special sort of guitar pickup, normally located next to the bridge, that is really six pickups in one. This is because the synthesizer unit needs access to the signal from each string in isolation, either to allow processing of the signal (such as frequency division and hexa-fuzz) or to derive a control signal to determine the pitch of oscillator(s) that produces the synthesized sound. Most of these processing techniques are practical only on monophonic sources; the divided pickup allows the synth to treat each string as an independent monophonic source.

Roland's first attempt at a guitar synth was the GR500 setup, which appeared in 1977. This consisted of a guitar controller (GS500), a 24-way cable and a synthesizer unit (GR500). The guitar was specially made for Roland by Ibanez, and was based on the Gibson Les Paul shape but with the addition of more controls and a different sort of pickup. As I explain in the 'Divided Attention' box opposite, most guitar synthesizers, including the GS500, use a special sort of pickup that is really six pickups in one. This allows the synthesizer unit to process each string signal in isolation so that each string frequency can be detected and used to drive each of the sections in the synth unit.

The GS500 also has a conventional, but rather bland, humbucking pickup so that a conventional electric guitar sound can also be produced. The guitar itself has a larger than usual number of knobs, most of which are volume controls for the various sections of the synthesizer unit.

The synthesizer unit is divided into five sections. The Guitar section controls the output from the normal pickup, which comes through an active tone/EQ circuit. This is a bit like having a wah-wah pedal permanently in the signal chain, and allows some fairly drastic modifications such as making a standard humbucker sound like a single-coil pickup.

The Polyensemble section produces, after some waveshaping and a static four-band EQ, the straight output from the divided pickup. There is also an envelope with Attack, Decay and Sustain controls that controls a VCA. The sustain control actually generates artificial sustain using a rather clever system that works by feeding the divided signal back up to the string that produced it. Under the strings, where the neck pickup would normally be, is a magnet that will repel and attract the string, giving you a very controllable feedback loop that maintains string vibration -- forever, if you so desire!

The Bass section divides the individual string frequencies by two, lowering the pitch by an octave, and again Roland GS-500static tone controls and envelope controls are provided. You can choose to have this section triggered either by all six strings, or just the lowest two or three. 'Voicing' gives the choice of two waveforms, described as 'soft' and 'hard', plus a percussion slider that adds a 'pluck' sound to the start of a note in the manner of an electronic organ. The output from the Bass section sounds a bit like the bass pedals from an organ, and can easily shake windows!

The Solo Melody section is much more like a conventional monosynth, complete with a recognisable VCO, (resonant) VCF, VCA, and an LFO. The VCO is monophonic with last-note priority, but the Polyensemble can also be routed to the VCF alongside the VCO. The earliest versions of the GR500 used the frequency derived from the string to determine pitch, followed by waveshaping circuitry to generate the sawtooth and pulse waves. This means that the synth section cannot be detuned to give the fat sounds we have come to expect from a lead-line synth. Roland realised this and fitted a system that derived the pitch from a VCO driven from the external synth section, allowing the solo section to be de-tuned by a control on the rear panel and also be influenced by the portamento of the external synth section. Apparently Roland UK retrofitted this for free, and my own example has both options available, selected by an additional switch on the rear panel.

Finally, there is an External Synthesizer section that allows you to control a conventional 1V/octave analogue monosynth. A clever touch is that external synth's volume can be controlled from the guitar.

The reaction of the guitar-playing public to the GS500/GR500 was lukewarm to say the least, as you could not Roland GR-300play it like a normal guitar. I should explain that playing any guitar synth requires a change in your technique: you must damp any string not in use, otherwise all sorts of strange noises come out of the beast as it attempts to convert your sloppy habits of a lifetime into meaningful sounds. As it was, the GS500/GR500 was primarily a synthesizer that happened to be a guitar, and it was perhaps too different for its own good. My own feeling is that if played as an instrument in its own right, the GR500 setup is capable of some truly unique sounds (oh all right, I'll come clean, I recently bought one and I love it to death!).

Second Coming: The GR100

Roland's second attempt at a guitar synth, which appeared around 1980, was, by contrast, an effort to make a guitar that also happened to be a synthesizer. This resulted in a series of guitar and synthesizer units that were simplified in appearance, but actually more sophisticated in the way they operated. A total of three types of guitar controller, with many variations in finish, were released. The G505 was derived from the Fender Stratocaster, while the G303 was an Gibson SG derivative, the G202 was a 'Strat'-shaped cross between the G505 and the G303, and the G808 was a super-deluxe version of the G303. All of these controllers plug into the GR100 (or GR300) synthesizer units using a 24-way cable, and all look very conventional on the outside, though examination of the back shows that there's a large amount of electronics inside them.

The GR100 was marketed as a large guitar effects pedal (as unlike the GR500 as possible!), so the new synthesizer units were designed to live on the floor. The bright-yellow GR100 had no control over envelope or pitch, but does have VCF controls; these were now situated on the guitars themselves. There was the novel idea of an individual fuzzbox for each string (Roland called this 'hexa-fuzz') coupled with a rather nice Roland chorus unit. Other controls varied Filter Modulation, Vibrato Rate and Chorus Depth, but little else!

The GR300

The guitar controllers for the GR300 were the same range that were offered for use with the GR100. In fact, when buying a Roland guitar synth (as I did in 1980), you purchased both items separately. The tasteful blue GR300 has six VCOs (one per string) that are controlled by the string pitches, as well as hexa-fuzz, plus an LFO, tuning presets and some control over the attack of each note. The decay of each note is controlled by the way you play the guitar, which makes the system far more versatile than it first appears.

As the sound sources on this unit include true VCOs, a few new techniques become available. Firstly, it is now possible to apply vibrato to open strings; secondly, each string can now produce two notes (one from the divided pickup and one from a VCO). The pitch of the VCOs can be offset by two preset controls that can be selected by footswitches. This has to be heard to be believed! Envelope attack can be slowed down, and you can individually select which strings will have a synthesized tone on them. There is a compression on/off switch, but the infinite sustain of the GR500 was dropped (shame!). Many of the GR300's functions can be selected by footswitches, the state of each of which is indicated by LEDs that flash if the relevant function is off or glow steadily if the function is on (this is very pretty in the dark!).

By this time, Roland had put more synth controls onto the guitar itself, making it easier to modify sounds while playing. All the guitars could control the following: Master Volume, Guitar Tone, Filter Cutoff, Filter Resonance, Guitar/Synth Balance, LFO Depth and Oscillator Mode. Oscillator Mode selected as a source either Hexa-fuzz,Roland GR-700 Hexa-fuzz plus VCOs, or VCOs only. The other cunning controls were two touch plates on the top and bottom edges of the bridge pickup that allowed the user to select Vibrato on/off either permanently (with the top plate) or as long as the bottom plate was touched. Touching the bottom plate also cancelled the effect of the top plate.

In parallel with the GR300 system, a bass guitar synth, the GR33B, was released, along with matching G33 and G88 controllers. This worked in a similar manner to the GR300, but with the addition of better envelope controls more suited to the bass guitar.

Final Fling: The GR700

The last Roland guitar synth system with a dedicated guitar to be produced, other than some specials by Gibson and Steinberger, was the G707/GR700, which appeared in 1984. To improve the rigidity of the guitar, the G707 added an ABS resin stabiliser bar in parallel to, and above, the neck. This resulted in a strange-looking instrument (nicknamed 'the cubist flymo' and 'the dalek's handbag'), that was also a pig to play, as whenever you looked at the neck all you could see was the stabiliser bar! The concept was correct, though, as I recently compared a G707 back-to-back with my own G808 and found the response of the G707 to be far more predictable (although I still hate the look of it).

The GR700 floor unit, however, was a huge improvement over its predecessor, as it was basically the guts of a JX3P adapted for use as a guitar synth. If you are unfamiliar with the JX3P, it is a six-voice, two-DCO-per-voice, conventional analogue polysynth. This was better than the earlier models because it was truly polyphonic with multiple triggering (ie. there were separate envelopes for each voice). Programming is possible through the usual process of selecting the parameter to be edited and then adjusting the single edit control (which was on the guitar). Editing could be made much easier by purchasing a separate PG200 programmer that had a knob (or switch) for each parameter.

The GR700 was also the first guitar synth to have a MIDI Out socket and memories. The MIDI implementation was crude by current standards, as it was fixed on channel 1 and did not transmit pitch-bend information (a criminal offence!). Even with the limited MIDI implementation, however, it seems to me that playing certain sounds from a guitar just sounds better than playing them from a keyboard -- and you can layer MIDI sounds with those from the GR700 itself. The sounds of the GR700 are as good as those from any comparable polysynth, with the advantage that you can also use some guitar techniques like finger vibrato on the notes you play. In an attempt to give infinite sustain, there is a 'hold' pedal similar to the sustain pedal of a keyboard that will latch the currently playing notes so that they continue playing even when the strings stop vibrating. Once notes are latched you can continue to play over the top of the latched chord with the straight guitar output or via MIDI -- weird, but useful.

It should be noted that any of the Roland guitar controllers, other than the original GS500, can be plugged into the GR700 -- which is a stroke of luck for me, as I hate the 'dalek's handbag' look.

The Green, Green GRs Of Home?

So, having experienced all the versions described, which one is the best? This is not an easy question to answer, as each generation seems to be so different from the others, each offering unique features -- but if I had to choose one I think I would go for the GR500. It seems to me to be true of a lot of first-generation instruments that they are more interesting than their descendents: as instruments become more refined, they become 'safe'. For me, the more bizarre features of the GR500 seem to encourage more unusual musical ideas, less rooted in traditional guitar styles. As I said, it's basically a synthesizer that just happens to be a guitar!

Copyright © August 1999, Sound-On-Sound