|
From: Bernard B. <ber...@gm...> - 2020-11-14 09:24:17
|
Dear all, I pushed a new version of the console and the interface in which we can specify which note has a "fixed frequency" when the scale is changed. Let me explain… Suppose that we fixed A4 = 440 Hz. If an equal-tempered scale is used, the frequency of C4 will be 261.63 Hz. Now let us use a "just-intonation" scale without changing A4. Since the C4 - A4 interval has changed (to a smaller value), C4 frequency will be 263.70 Hz. This may sound OK but it will create problems if several instruments use different scales, or if the scale of an instrument is changed during the performance to do (what I call) "enharmonic adjustement", for instance replacing Pythagorean major thirds or sixths by their harmonic equivalents. In these cases we may want a certain note to stay at the same frequency. In Indian music it would be "sa" = C, but different situations may occur with different tonal systems. Keep in mind that the mechanism implemented (using Csound's convention) is able to define scales with more/less than 12 intervals and an "octave" interval more/less than 2. So, in the settings we now have a slot for a key number telling the console which note should remain "fixed". By default we can set it to C = 60 or 48 or 36 etc. It is not unlikely that this "fixed note" will be different for different scales and in different contexts. For this reason I plan to implement the "_scale()" tool with 2 parameters, one for the scale and the other one for the fixed key number; with value 0 if same as the previous value for the same scale. The good news is that it opens BP3 to communities of musicians eager to play with "just intonation" and all sorts of microtonal scales, some of which "extra-European". They will only need to install Csound! Now I am working on the "_scale()" tool ;-) Bernard |
