I think I read on this forum a while back about an (ardunio based ?) box which allowed for midi events to be filtered / changed / created and incorporated into an existing midi chain. This enhanced the midi capabilities of the Octatrack. Am I going mad ? or does this exist ?
Otherwise, I can´t remember any other names/projects.
However, you also got the MidiSolutions Event Processor Plus widely aviable. Which may fit your needs?
the mutable instruments folks make some tasty midi gear that may help with that - it’s also possible with a bit of effort to do this with a Raspberry Pi in case u have one lying around - i’m unaware of the particular arduino solution which no doubt exists in a number of guises
The rackmount Digital Music Corp MX-8 (really old, used only) has lots of filtering options. This is what I use at home and I’m pretty happy with it - one thing I like about it is it requires no computer to edit - it’s pretty fast.