Roland Rhythm 55
The Rhythm 55 had analogue voice circuits to produce its drum sounds, and offered approximately 20 permutations of preset rhythms.
The Rhythm 55's drum voices are listed below. (They are the same as for the Rhythm 33.) The sounds are generated by analogue synthesis techniques, and, as is typical with this technology, the sounds themselves, although possessing a certain musical charm, are not particularly realistic imitations of their acoustic namesakes.
The following voices are generated by "tuned resonance" type circuits:
The following voices are generated by shaped white noise:
The only control on the front panel for adjusting the sounds is a balance control, which alters the relative levels of the bass drum and the cymbal/hi hat/maracas sounds.
The Rhythm 55 offers the user around 20 preset rhythms. There is no way to adjust the preset patterns per se, or to program your own patterns. The only control available is a (uncalibrated) knob to adjust the tempo, and a push-button which doubles the tempo. However, it is possible to select more than one rhythm at once, and also to effectively "mute" drum sounds from a pattern using the balance knob (see above), thus providing more possibility for rhythmic variation than might initially seem feasible.
Main preset patterns:
Additional "variation" patterns:
- "4 beat":
- bass drum
- bass & snare drum
- foxtrot 2
- swing 2
- swing 3
The Rhythm 55 can not interface with other instruments (e.g. to synchronize its tempo with another machine). The Rhythm 55 has a mono audio output, available on two unbalanced phone connector sockets—one socket is high impedance, the other low impedance.
Roland Rhythm 55 Service Manual.