The processor board receives the MIDI signal from the MIDI file player and converts it from a serial format to a partially decoded serial/ parallel format. There are two decoder processors on the processor board, each providing partially decoded data lines for 64 outputs.
The valve boards are connected to the processor board by two 24 conductor ribbon cables. Each cable contains 8 serial data lines, 4 decoder logic lines, plus 19 volt, 5 volt, and power supply common lines. Each of the 8 serial data lines contain data that will become 8 parallel outputs after final decoding on the valve board. Jumpers on the valve board select which 2 of the 8 data lines are decoded to provide 16 discrete parallel outputs for the 16 valves on each board.
The note mapping of each decoder chip on the processor board allows any valve to be programmed to respond to any MIDI note/ channel instruction. In an E-Roll, all the tracker bar signal information is stored as MIDI note on-off data including the expression data. The musical notes and expression “notes” are in the same order in MIDI as they are on the tracker bar. The actual valve that responds to each “note” is programmable by following the note mapping procedure, and is preset for the particular installation when the VirtualRoll is prepared initially.
Original paper rolls are deteriorating continuously, eventually becoming so fragile that they disintegrate when they are played. The roll scanning effort began as a means to preserve the music that would ultimately be lost forever as the original paper rolls self destructed.
Aside from the preservation aspect of the scanning and conversion to MIDI e-roll format, the resulting digital files provide an economical media for building a new library of roll data (rolls). This means that a new owner of a pneumatic instrument can acquire a “roll” collection for his instrument at a fraction of the cost and storage space of actual rolls.
More than a few well restored instruments remain unused because their owners never acquired a significant and varied roll collection. The few rolls they own became boring, and the instrument is ignored as a result.
This fortunate coming together of technologies is the best thing to happen to the preservation and enjoyment of mechanical musical instruments since their invention.
Thousands of original paper piano rolls have been electronically scanned and preserved as E-Rolls. These e-rolls are available from a number of sources. Additional paper rolls are being scanned constantly with techniques that provide accuracy equal to that of the original perforator master. (Click here for scanning info from Warren Tractman)
The VirtualRoll was conceived, engineered and developed over a 10 year period by an industrial machine designer and restorer of player and reproducing pianos, resulting in a system that provides the ultimate in performance, reliability, ease of installation, and reasonable cost.
For more information, or to purchase a VirtualRoll system please send email to: firstname.lastname@example.org