I've tried using the built-in accelerate parameter in a huge number of ways -- with and without n, with synths and with samples, over all kinds of value ranges -- and it never seems to do anything.
I also tried to add the muffle parameter, which superpiano suposedly uses, and can't get it to do anything either. I made this change:
and then running runhaskell generate-params.hs > ../src/Sound/Tidal/Params.h from the root directory. Now muffle is recognized by Tidal but also doesn't seem to do anything.
I don't know what's going on exactly, but keep in mind "superpiano" hooks into the MdaPiano UGen, which unlike almost every other Supercollider synth internally rounds the frequency input to the nearest MIDI note and I don't think supports any kind of pitch glide (like accelerate). So "superpiano" is always going to have odd behavior.
Accelerate works fine for me on other synths but I think my SuperDirt is a actually a bit out of date, so I should check on the newest version.
Is anyone using their own custom parameters for anything? As suggested in the docs for SuperHammond, I just tried using vrate and vibrato, which I defined the same way as described in the OP in this thread, and while they do something it doesn't sound like vibrato at all.