Roland GR-300 Guitar Synthesiser
by Peter Maydew
Electronics & Music Maker - Nov 1981
The word 'synthesiser' by itself is usually taken to mean one which is controlled by a keyboard; synthesisers meant to be played by musicians who are used to other instruments always have a qualifying word in their description, such as 'wind synthesiser' or 'guitar synthesiser'.
There are quite a few such devices about nowadays, and with good reason: musicians do not want to give up the techniques they have learned and swap to keyboards in order to become synthesiser players.
In addition, there are effects easily available from a guitar (for example) which simply are not possible on a keyboard without extra 'performance controls' as they are called.
The main reason for the supremacy of the keyboard as a synthesiser controller is its simplicity — each note is selected, and simultaneously played, by the pressing of one key only. A contact can then be arranged under each key to route a voltage to a voltage controlled oscillator (VCO) and to make the appropriate pitch sound.
On a wind synth, on the other hand, the notes are defined by one or more keys in combination, and sounded by blowing, so that some complexity is needed just to work out what the note ought to be. In addition, a breath operated switch is necessary to detect whether or not the player is blowing.
The Lyricon works on the above principle, and works very well, but the problems are multiplied for an instrument like the guitar. It is possible, for instance, to detect which strings are being pressed on to which frets by a simple electrical scanning, and some guitar synths employ this principle; but there are several guitar techniques which will not be picked up this way. Harmonics, for instance, where the note sounded is an octave or more above that actually fretted; and bending and finger vibrato, where once again the string stays fretted at the same place, but is stretched so as to increase its pitch.
An alternative approach is to employ a device called a pitch to voltage converter, or P to V, which works a little like a VCO in reverse. The instrument's actual sound is fed into the P to V, which sorts out which note is being played and passes this information in the form of a voltage to the VCO.
Guitars are quite difficult to trigger from in fact; as a note decays the second harmonic becomes louder than the fundamental, and primitive P to Vs have a distressing habit of leaping up an octave as the sound decays. A chord, of course, will give any pitch detector a fit of the vapours straight away: which note out of the six does it lock on to?
Early guitar synthesisers employed a six channel (hexaphonic) pickup with a separate output for each string — then the loudest string was detected and passed on to the P to V; you could still only synthesise one note at a time, of course, six oscillators and six pitch to voltage convertors being needed to produce a truly polyphonic instrument, and this is where Roland step in and the instrument in question actually gets reviewed.
The G-808 Guitar
Instead of giving you a hexaphonic pickup to screw to your own guitar, Roland make you buy a whole guitar with the pickup built in. The main disadvantage is that you cannot use the GR-300 with your favourite '58 Les Paul which you picked up for $30 in an Alabama pawnshop. The advantages are several — the most used synthesiser controls may be mounted on the guitar, where they are easy to alter during a performance, and the critical pickup is already adjusted and mounted for you in the best place (near the bridge, where many guitars do not have room).
One man's guitar is another man's firewood as we all know, so Roland offer four different guitars, all with normal guitar pickups in addition to the synthesiser pickup so they can be used as straightforward electric guitars via a standard jack socket.
The G-303, the one I tried, is a fairly standard Japanese style twin cutaway design with two twangy Japanese style humbuckers. The G-808 is basically the same but has its neck laminated through the body: the G-505 is Stratocaster inspired and has three single coil pickups and a vibrato arm, whilst the G-202 is also Strat shaped but has two humbucking pickups.
This is supposed to be a synthesiser review, so I will not attempt to assess the guitar except to say that it was well-made (as it should be for the price) and would not disgrace any player not afflicted with Gibson/Fender mania. In fact, the sample I played had been well used in the Roland roadshow prior to me getting my greasy fingers on it, and the strings were rather neglected; it is a credit to Roland's pitch converter circuitry that the synthesiser triggered impeccably off such a horrible signal.
The straight guitar controls are quite sparse — just a pickup selector, overall tone control and master volume which also controls the synthesiser volume. The rest of the knobs belong to the synth section: a balance control which mixes synthesised and straight guitar sound in any proportion; cut off frequency and resonance for the filter; vibrato depth, and a 'voice' switch. This enables you to feed the filter either with oscillator signal, or with the output of six independent distortion circuits, one for each string so there is no intermodulation; a very nice effect by itself. Finally, there are two touch plates, one on either side of the bridge pickup which switch vibrato on and off, or alternatively enable you to just dab a bit in here and there whilst playing. All this lot is fed via a decent (five metres) length of 24 way cable and two sturdy connectors into the GR-300 which goes on the floor like any other effects pedal.
Mere effects pedal it is not, of course, but the GR-300 does not have the same facilities as a keyboard synthesiser. For example, there is no envelope shaper at all; the synth follows the guitar's envelope, and the harder you hit it, the louder it plays. Slow fade-in 'violin bow' effects have to be done manually with the volume control, which is conveniently placed on the guitar so that you can turn it with your little finger whilst playing. Secondly, there is only one overall filter instead of one for each string, so that more harmonics are cut off the top strings than from the bass ones.
There are five foot switches along the front, with an indicator LED for each so you can see how they are set. Two of these are for pitch transposition; in addition to a master tuning control, there are two preset pitch knobs, A and B, each with a range of one octave up or down from the fundamental guitar pitch. The associated foot switches A and B can be made to work in two modes — latching, where the transposition is permanent until you tread on the switch again, or unlatched where the transposition is only effective for as long as you hold the switch down. Pitches A and B cannot both be selected together, but the Duet foot-switch brings in the guitar's fundamental pitch in addition to the transposed sound for instant single-handed harmony playing; or if no transposition is selected, a slight detuning can be performed to make a richer sound.
Portamento, or glide between notes, may be added; unusually, with separate control over rise time and fall time. Six slide switches enable the player to disable each oscillator, so that the synthesiser triggers only on a limited number of strings: for example, it is possible to have a bass line derived from the low E string accompanying a straight guitar part, or a melody can be picked out from the middle of a suitable chord sequence.
Two foot switches and two knobs control modulation of the filter. The filter is sensitive to your playing, i.e. the harder you pick, the more harmonics that are let through, and the 'Sens' control determines the extent of this effect. 'Attack Time' slows down the onset of the filter sweep. One footswitch turns the modulation on and off, the other inverts the effect so that the filter sweeps down in frequency instead of up. Finally, there is a compressor which prolongs notes in the usual fashion when turned on. It is actually possible to turn the knobs with your foot provided you have not been hitting the bottle during the sound check, but in case there still are not enough controls for you there are sockets for more on the back of the unit. A pedal can be connected to the filter for wah-wah type effects, and there is provision for three extra foot switches. One switches the compressor in and out, the second cancels the glide effect if there is one set up, and the third brings in all six oscillators regardless of the string selector switches.
It is not necessary to buy the synthesiser straight away, of course; you could just play one of the guitars by itself until you have saved up for the rest of the gear. If the synth is still too much, then Roland also make the GR-100; although it plugs into the same range of guitars, it is not a synthesiser at all. Instead of oscillators, it has just the six channel distortion which is filtered in the same way as on the GR-300. There is no transposition or glide, but all the controls on the guitar except the voice switch work in the same way; so there is vibrato, rather cleverly done with a delay line which can also provide a chorus effect. I did not try out the GR-100 for myself, but at £350 the price saving does not seem worth the loss of flexibility.
Although the GR-300 is short on synthesiser features compared to a keyboard instrument, the controls provided are those that are likely to be of the most use, and have obviously been carefully thought out with live playing and the reasonably non-technical guitarist in mind. The outstanding feature of the device is its responsiveness to the player's technique; you can play it just like any other guitar without having to alter your style at all. There are a wide range of sounds available ranging from the beautiful to the grotesque, and you can be as subtle or unsubtle as you like; bend the strings, use vibrato, play it with your nose (as I once saw John Williams do on a classical guitar) and it will follow where you lead.
If you want convincing, try the GR-300 out with only the sixth string oscillator on, tuned an octave below your guitar; then calculate how much you can save by firing your bassist! Bass unemployment is not Roland's intention, of course, because they also make the G-33B bass synthesiser with a choice of two bass guitars to go with it, but it is a tempting thought; in fact, with a decent drum machine and the GR-300 you could sack your whole band...
The GR-300 is £515; the cheapest guitar (the G-202) is £299 whilst the1 G-303, G-505 and G-808 are £399, £425 and £499 respectively. These prices are inclusive of VAT.