Firstly, I've been waiting years and years for something like SamplerBox! A lightweight module that you can load samples onto and play using a midi keyboard(s) - without spending $2000+ on a Nord Electro (which has this feature). I'm so happy to have stumbled across this!! I ordered my first Pi yesterday (Pi3) and am expecting it in... hm, a few weeks (ordering from O/S because it's still cheaper than buying from here in Australia :'( ), so finding this portable version (http://www.samplerbox.org/forum/9) has really made my day! I can see this being a valuable tool for when I want to prepare and test sample libraries without the SamplerBox handy -- perhaps a band member has borrowed it and I want to update the sample library for them, maybe in a shared Dropbox folder. Ahh the possibilities!
I have one question/minor concern re: latency. From what I've read here no one's been experiencing latency issues (at least not using the recommended USB DAC). I'm using my PreSonus AudioBox iOne and getting noticeable latency even with a buffer size of 64 - not much, but enough to affect my playing. Latency isn't noticeable with this DAC in Ableton (same buffer size - even 128 is fine). Should I be worried? Or will all be fine when I get my Pi? Surely my latency would be lower on my PC - which is why I'm worried.
This is probably not the way to go about it, but I printed defaultLowOutputLatency and defaultHighOutputLatency which gave me values of 0.09 and 0.18, which seem pretty low (fyi this is my first Python project). Curious though, these numbers are unaffected by a change in buffer size. I see that Joseph is favouring sounddevice over pyaudio now - perhaps this will make a difference (although I haven't figured out how to include this dependency in the portable version)..
Again, awesome work and I look forward to further delving into the world of Pi, Python, and SampleBox!