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JoeT wrote:
>The main question is: How precise are the sensors? I don't think they really can differentiate 127 values. At most a few dozens.

I'm fairly sure they can. But do they? Only the R&D folks know for sure but here's why I think, yes they do.

Say I use a clock as slow as 400 kHz (2.5 microsecond ticks) and 2 optical encoders spaced 5mm apart. I think that to avoid aliasing I need 2 clock cycles so that's 5 microseconds to detect 5mm of motion, a speed of 1 mm per microsecond. The equivalent of 1000 meters per second and I don't think I can strike that fast, but it could measure it if I could without breaking it. So there's no practical upper limit to the sensors' ability to measure velocity What's the lower limit? That depends on how big is the counter they use. If they have a 24 bit counter it could wait 16 million clock cycles for someone to finally hit the bottom of the key, that's several seconds to move 5 mm, slower than an ant, I can't play that slow. So with those assumptions the sensors are more than fine. I think the numbers I just gave are conservative, feasible, and I think there's room for them to save money by slowing the clock down, shrinking the encoder distance, and use a cheaper 16-bit counter and still be good enough.

I agree, but I would write it otherwise : 1m/s at 5mm needs 5ms. A clock cycle at 400kHz is 0.003ms. The 5ms is 2000 clock cycles : you have a quite good relative accuracy.

I think it's mostly the rubber domes themselves, which are not that precise. Their time of making contact varies with each key press. So the last 3 bits of the 7 bit MIDI velocity are somewhat random.

Leaving aside the specific metrics involved, I would say any development that moves digital instruments back toward an analogue curve in any specific area is welcome. I recall that when CDs were first introduced, some people expressed an opinion that there was something "not quite right" or "cold" about the sound when compared to vinyl or tape, but they really couldn't pinpoint it. I very much doubt they could discern the discrete "jumps" in volume and quantization at 44.1kHz, but they may have picked up the "blockiness" subliminally after being so used to analogue reproduction.

The other day I was listening to a recording I had made a couple of years ago using a Nord piano. I loved the sound (Italian Grand, I think) on this quite lyrical piece, but I was disturbed by the very slightly "robotic" nature of the playback - even though I had played it manually. It sounded like most notes were at the same volume level - even though I thought I had played it expressively at the time. Now, I'm not a fan of the Fatar TP40 action, but it's not that bad. I think that I was picking up on the granularity of the MIDI steps. Instead of minor variations that inform you of human input (even though you can't pinpoint the actual steps), I was somehow hitting the same volume levels too often. If I had been able to play using hi-res MIDI, that would have been much less likely to occur. So, being able to accurately repeat specific MIDI values may actually be a detriment to expressive musicality.

vox: Are you sure it's caused by YOU? Or caused by MIDI? Perhaps, instead, it's the piano software/library? Maybe the piano responds to MIDI velocity 60 exactly the same as MIDI velocity 61. And 62. And 63. Maybe it doesn't change until you reach velocity 64?

I'm not sure of anything, Mac; that's the problem. It's a kind of psychoacoustic black hole! But the main thrust of what I'm saying is that there's no detriment (that I can discern) to helping digital instruments more accurately emulate a natural analogue curve.