Bc2000 (for the BCF2000 & BCR2000)

--- In bc2000@yahoogroups.com, "budwardp" <budwardp@...> wrote:
> does anybody know what kind of resolution the foot controller input
> is capable of?  I've read that it can output 14 bit pitch bend - but
> I'm wondering at what bit depth the input is sampled.
> 
> Most controllers seem to be 7 bit (0-127) which are then output as 14
> bit numbers with large gaps between each number.  Or, as in the case
> of many faders (such as on the bcf2000) 10 bit (0-1023.)   Very few
> do 12 bit (0-4095).
> 
> I'm really hoping that the bcf2000 will give at least 10 bit.
> 
> (A simple test would be to output the foot controller as pitch bend
> and see what the smallest incremental change is.)

First of all, your "simple test" was a bit tricky to perform: the BCF's "standard" Pitch Bend setting leads to 7-bit output, since the LSB value is always 0. (See "BC MIDI Implementation.pdf" (section 16.5) at http://home.kpn.nl/~f2hmjvandenberg281/ .)

However, there is a way to get a higher resolution, namely by defining a "custom" setting for the foot control, specifying the individual bytes of the pitch bend message (e.g. "$E0 val0.6 val7.13") and specifying the full 14-bit range (0-16383).

This gave me the following output values (using my Roland EV-5 pedal):
0. 16, 34, 50, 68, 84, 101, 118, 135, ...

I've tried the same settings for two faders, each with the following results:
0, 16, 33, 49, 67, 83, 99, 117, 133, ...

Conclusions:

The fader output values differ from the foot control output, and neither has a fixed step size.
So the BCF doesn't seem to impose any limits in the digital domain: it doesn't automatically set any bits to zero.

The varying step sizes must reflect limitations in the electrical, analog domain.
In general the step size lies around 16, so that basically amounts to a 10-bit resolution (14 bits minus 4), with 1024 different values (16384/16).

Hope this helps,
Mark.