The GR-300 is an analog guitar synthesizer released by Roland Corporation back in 1980 and continued to be one of the best pieces of analog guitar synthesis equipment for a long time. Roland advertised the GR-300 as a synthesizer that is able to produce effects and nuances that were impossible for the keyboard synthesizers of the time to easily produce. In fact, in order to produce the effects delivered by this synth you would actually need six octave shifters, six compressors, six chorus machines, six distortion units, six phase shifters and much more. Best of all, the major functions of the GR-300 are all controlled via your feet switches, which means you don't even have to use your hands to operate it. Not bad for a synth that can produce anything from simple or complex solo sounds to huge band or orchestra sounds. Of course, this also meant that the GR-300 was great for live performances. Also, it's possible to connect attachments between the GR-300 and an external amplifier, so you can use chorus, flangers, phase shifters and any other devices designed to work with synths.
What set the GR-300 apart from the competition was the fact that it could produce stable effects for virtually all styles of guitar playing. This includes hammering, chopping, harmonics, glissandos and more. This is something that was impossible to accomplish before the release of the GR-300. This was a big step up from the GR-500, it's predecessor, which suffered from serious tracking issues that limited its usefulness. The only thing that you had to keep in mind was to keep any fluorescent lamps, neon lights, and high power transformers away from the GR-300 as these would produce high noise levels in the synth.
The GR-300 has a rugged appearance, which is good for something that is going to be on the floor most of the time. In terms of features and specifications, this synth offers 6-voice polyphony, 2 oscillators per voice and VCOs that are directly harmonically locked to each string. However, these can still be tuned separately as well. It has an LFO for vibrato effects and can output either the guitar, the synth, or a mix of these two. One of the most notable users of the Roland GR-300 is Pat Metheny, but other notable users include Andy Summers (The Police), Robert Fripp and Adrian Belew (King Crimson), and Pete Townshend (The Who).