A month late but this might be helpful.
There are a lot of Roland synths that support Polyphonic aftertouch which prompted me to write
a channel aftertouch to last key aftertouch converter.
If you have a keyboard with channel aftertouch and an XV or Fantom or Soniccell etc you can at least get to try it out, all be it in a limited way.
https://www.bwalk.com.au/ChannelToKey/ChannelToKey.html
Time for the real thing. So I searched around for a keyboard controller with Polyphonic Aftertouch (or Key Aftertouch or PAT) and other than the rare Ensoniq syths from the 1980's and the even rarer huge Kurzweil Midiboard, there were the Roland A-30,A-50 and A-80 midi controllers.
https://www.youtube.com/watch?v=T5GvR3Vf2KY
Perfect!, but I couldn't find one. So searching though most of the Roland keyboard controller manuals looking for PolyAT or KeyAT or something similar, I found the Edirol PCR-300 500 and 800 from 2005 that Roland said had PolyAT (sometimes calling it KeyAT) and I bought a PCR-500 on ebay.
Like yours, the keyboard that arrived had channel aftertouch that is very heavy and usually can't be pressed to get the 127 max easily.
(This is like my Fantom X8. It was bought new so I know it was always like this)
Inside there is what appears to be a force sensitive resistor strip with thick felt above it. This is attached to the circuit board where there is a small PCB mounted trimmer pot. I marked the original position and there was only 10 degrees of rotation to the max stop. At max it did improve, but not by much, but it is easy to try out.
There looks to be an op amp following the trimmer, so you could swap out the op amp's feedback resister for a bigger one to increase the gain. - I might try that.
Unfortunately it does involve soldering small components.
I have to say my PolyAT excitement turned to great dismay and it took me a while to realise that despite my detailed reading, I had been tricked by Roland.
There is NO real PolyAT on the keyboard.
The 16 Pads (button switches) do have separate keyAT and I can see a use for that.
The keyboard does indeed put out "Key aftertouch" but most definitely does NOT put out polyphonic KeyAT.
Polyphonic aftertouch on a keyboard is used for separate control of more than one note at any one time.
It has 3 Midi bytes.
Status(PolyAT)+Channel, Key#, Value#
Yes the first data byte is called "Key number"
So, obviously, at any one time you should be able to have each key with a different PolyAT value.
Unfortunately Roland only allows you to swap Channel AT for a single note KeyAT.
It's not even dynamic like the last note AT in my software.
You have to program the note number in first.
Please can anyone give me a decent use for varying a middle C's AT when I am pressing G4
There is NO real keyboard PollyAT in ...
Any Edirol keyboards - so if it is PCR controller forget it.
Roland A-49, A-88
Roland A-300Pro 500Pro 800Pro - at least there is comment in the Midi spec saying the keyboard doesn't have it.
Even their latest A-88MkII that is 'the first thing that is Midi 2.0' ready doesn't have polyAT despite the MPE (that is Midi Polyphonic Expression) coming before Midi2.0. So don't get excited. It is a just marketing BS.
The Roland controllers that do have PollyAT are only the A-30 A-50 or A-80 from the late 1980's - please let me know if you know any more.
As you can see I'm pissed off as I have a lot of keyboards and don't need this (reasonable) keyboard.
I only wanted it for keyboard PollyAT, but then again I didn't pay much.
Polly AT is seen to be expensive as there needs to be a circuit on each key, but today even with high speed Arduinos you can do this .
Ensoniq used coils printed on the circuit board (clever for the time). Kurzweil apparently uses magnets and probably Hall effect devices. I can't see massive expense.
I believe this is also used in Expressive-E's Touche and Harken Continuum.
The Expressive-E's Osmose looks interesting, but expensive.
If the Australian dollar ever improves, I might save up to get an ASM Hydrasynth just to get the controls (it has a long ribbon control as well) that were available on the CS-80 back in the last century.
With the current value of a Yamaha CS-80, clearly someone cares for musical expression in electronic music and not just for Vangelis covers.
(I'm sure I will calm down soon)
Stay well
Royce
