The CR-78 uses analog drum voices, which sound very little like real percussion instruments. The unit also incorporates an NECmicroprocessor to provide digital control of its functions. Previous Roland drum machines had offered only a selection of preset rhythms. The CR-78's key new feature at the time of its introduction was that in addition to offering 34 preset rhythms, it provided four programmable memory locations for storing patterns created by the user. These can be created by using step programming with the WS-1 box, which was available as an optional extra. The four user patterns are stored in RAM memory; when the CR78 is switched off, the contents of the RAM are maintained by a NiCdrechargeable battery. The CR-78's front panel allows the user to customize the preset rhythms by altering the volume balance between bass and treble sounds, canceling some sounds altogether, and adding "metallic beat". Many of the preset rhythms have a memorable character, and the ability to manipulate them further made the CR-78 a versatile instrument. No digital control of tempo is provided on the front panel, with only an analog knob for tempo control. However, the CR-78 accepts an external V-trig clock, allowing a control voltage to be fed in from another device such as a music sequencer. A selection of preset fills and rhythm variations are also available, either to trigger manually, or automatically every 2, 4, 8 or 16 bars. Some of these fills were used in synth-pop songs such as "Enola Gay" by Orchestral Manoeuvres in the Dark, and "Underpass" by John Foxx. Roland also produced a simpler drum machine, the CompuRhythm CR-68. This was essentially the same as the CR-78, but without programmable patterns or the ability to fade drum sounds in and out. A large cabinet version, the CompuRhythm CR-800, with capabilities between the CR-68 and CR-78, was also produced. At the same time Roland also sold the TR-66, a smaller unit which offered fewer preset rhythms and no programmability.
Sounds and rhythms
The CR-78's built-in rhythm sounds were a further development of those available on the earlier Roland Rhythm 33, 55 and 77 machines. The analog percussion voices consist of bass drum, snare drum, rim shot, hi-hat, cymbal, maracas, claves, cowbell, high bongo, low bongo, low conga, tambourine, guiro, and "metallic beat". The CR-78 has an accent control, which increases the loudness of certain steps in a pattern. There are four patterns named "Rock" and two named "Disco". Other patterns are named "Waltz", "Shuffle", "Slow Rock", "Swing", "Foxtrot", "Tango", "Boogie", "Enka", "Bossa Nova", "Samba", "Mambo", "Chacha", "Beguine" and "Rhumba". Each pattern is available in two variations, labelled "A" and "B". It is possible to select more than one rhythm at a time, and also mute drum sounds from a pattern using the balance knob and dedicated cancel buttons. The CR-78 has been used in songs including "In the Air Tonight" by Phil Collins, "I Can't Go for That " by Daryl Hall & John Oates, "Mad World" by Tears For Fears, and in live performances by Radiohead.