[bp-dev] Time-base

[Bernard B. <ber...@gm...>]

Dear all,

A very practical feature of BP2 — at least for educational material — 
has been left out from development for the main reason that it stopped 
working properly. I mean the "Time base", see enclosed picture.

It was working up to the MacOS 9 version and perhaps started being 
erratic as I dropped the in-built MIDI timer for OMS. Today, if you 
click the "PLAY TICKS" button, you will hear ticks without connection to 
what has been programmed. On the picture we have a default 4 beat 
sequence in which the first tick is played on key 96 and the following 3 
ticks are on key 84. Thus, you can program as many of 3 cycles of 40 
beats each, and even set up each cycle for a different speed ratio. This 
opens on very intricate rhythmic patterns. We used it to model most 
rhythmic cycles (tala) used in North Indian music. See for instance the 
enclosed "rupak" 7-beat cycle.

This feature is educational in the sense that a sophisticated metronome 
can highlight rythmic patterns which most listeners would not identify 
in a musical piece. An example is "-gr.Visser.Waves": it sounds 
"arythmic" because of its complexity. However, superimposing a cycle of 
5 beats renders the pattern audible. I remember having done it in a 
conference at Cambridge UK to convince a musician/linguist that the 
"waving" effect wasn't the result of randomization but of a 
self-imbedding polymetric structure.

How can we revive this in the next version? It is probably easier than I 
had anticipated. I will construct the same interface in the PHP 
environment so that time base cycles can be created independently and 
checked via the MIDI file player. Then the sequence will be sent to the 
console along with the grammar or data expected to produce the musical 
item. It may be sent as a sequence of time-stamped MIDI bytes or a MIDI 
file; the format is not important because timings will be exactly the 
ones expected to fit with the musical item. The console will only need 
to mix these codes with the ones it is sending to the MIDI sound device.

So, the complexity of editing a time base cycle will entirely be taken 
care of by the interface.

It's on my "to-do" list after the stay in mountains. ;-)

Bernard