>> A very abstract thought: Could "binary" be replaced with "discrete"?
>> For all I know, "binary" is totally correct -- the Welte concept even
>> used 4 binary rows to encode around 12 discrete levels of vacuum.
>
> [ Don't you mean the 16-level Duo-Art system?  -- Robbie ]

What I meant (and mixed up), was

(a) the 3-hole Ampico system, which (according to Art Reblitz's book)
had intensities 2, 4, and 6 which resulted in 7 useful combinations,
as 2+4=6; and I guess that "no suction" is not punched anywhere (you
would just not punch notes there, wouldn't you?), so you end up with
six levels.

(b) the 4-hole systems, which actually has 15 non-zero suction levels
(again dismissing the zero suction).

Or are there reasons to punch a zero suction level?

Regards

Harald M. Mueller

 [ "Zero level" is not zero suction; rather, it is the minimum useful
 [ suction to play the softest notes.  Since the friction of the
 [ piano varies with humidity, an adjustment for "zero level" or "zero
 [ intensity" is usually provided.  The Duo-Art roll sent 16 discrete
 [ levels as commands to the expression system, the Ampico A roll codes
 [ commanded seven different levels.  -- Robbie