The Roland TR-505 Rhythm Composer was released by Roland, in 1986. It is a drum machine and MIDI sequencer from the same family as the Roland TR-909, TR-808, TR-707, and TR-606. The drum kit includes basic rock drum sounds similar to those of the TR-707, plus a complement of Latin-style drum sounds similar to those of the TR-727
Voice synthesis
8-bit unsigned PCM data, with a 25.00 kHz sampling rate. The TR-505 is not a cut-down baby brother of the TR-707. Instead offers some major improvements including 16 digitally recorded PCM drum sounds. Also including five Latin percussion voices, eliminating the need to buy a 'Latin version' or PCM carddown the road. Summary of Drum Voices::
Although there are 16 samples the TR-505 only 8 voice polyphonic. This means some samples are restricted from played simultaneously: Low Conga or Hi Conga; Timbale, Low Tom, Mid Tom, or Hi Tom; Low Cowbell or Hi Cowell; Hand Clap or Rim Shot; Crash Cymbal or Ride Cymbal; Closed Hi-Hat or Open Hi-Hat. There is almost no voice editing in the TR-505. The user is limited to setting the Volume, Velocity, MIDI Channel, and MIDI Note of each voice as a global parameter.
Sequencer
The TR-505 contains 48 factory sequencer patterns, organized into 3 pattern groups. The drum machine also contains 48 user created sequencer patterns, organized into 3 pattern groups. The TR-505 features five basic modes, including the following:
Track Play - plays whole tracks.
Track Write - sequence patterns into tracks.
Step Write - sequence patterns by stepping through each position in the pattern.
Real time - play patterns in real time by tapping the pads.
An accent can be applied to any position in a pattern and will affect all instruments triggered at that position by increasing output volume. You can Copy, Insert, or Delete one or more steps in any given pattern.You can also Copy, Insert, or Delete patterns anywhere in a track. Each individual pattern is a single measure long, The default time signature is 4/4 consisting of 16 steps and quarter note scale. This results in each step representing a sixteenth note. Other time signatures can be programmed by changing the Last Step and the scale. This can also result in shuffle and swing rhythms. Two or more Patterns can be combined, using Pattern Chaining, to play as a single pattern. Each pattern in the chain occupies a pad, but will only trigger the whole chain, not the individual pattern. Up to six tracks can be programmed using combinations of patterns. Each song can consist of up to 423 bars.
Keyboard and external control
The TR-505 consists of 16 individual instrument/ pattern pads. The pads are not velocity sensitive. The TR-505 can transmit and receive on MIDI channels 1 -16 and Notes numbers 25 to 99. It also contains a MIDI Omni mode allowing it to receive all MIDI data. The TR-505 responds to the following MIDI messages:
Key message - trigger signal for the individual voice.
Velocity message - Note-on velocity is both transmitted and received allowing more expressive.
Track Number message - track/song select
Bar Number message - Song position
Clock message - tempo synchronization, start, stop, etc..
Storage
Storing 48 ROM patterns, 48 RAM patterns, 6 tracks, and a maximum of 423 measures. The Tape interface allow the Tracks and Patterns in internal memory to be stored on external tape. Data can be Saved, Verified, and Loaded from tape.
Modifications
There are companies, websites, and magazine articles documenting a DYI process for circuit bending and modifying the factory setting of the Roland TR-505. An example of a few modifications include: changing audio samples, voice circuit bending, adding individual audio outputs, adding CV outputs, adding pitch change to each voice, and adding circuits to randomize sequences.
