I’ve worked on the drum engine in the last days. The concept is frozen, most of the code is implemented, and now it needs a lot of testing (from my side) in order to check, if the engine is doing what I initially planned.
So, it was time to work on some teasers! ;D
Some words to the concept: each patch contains 16 drum patches, which either can be played directly from a MIDI keyboard/sequencer, or from the internal sequencer, which works similar to the bassline seq - means: you can select the sequence via MIDI notes, so that they can be controlled interactively. More words to the sequencer in the next teaser 
Since the memory of a patch is limited, a drum only consists of 8 parameters. But only might be the wrong word, because each parameter changes the drum timbre dramatically!
Instead of editing wavetables, or tweaking on ENVs/LFOs (which can be very time consuming and is not the intuitive workflow you would expect from a drum synth), there are prepared “drum models”, which are hardcoded in the firmware. In theory up to 256 drum models can be implemented.
Drum models currently only exist of waveform/note tables. Within the patch It’s possible to change the tuning, the ADSR parameters, the gatelength, the WT speed and a special “WT parameter”, which modifies a variable part of the wavetable.
Ok, enough details, just listen to the examples:
Bass Drum Model #1 and #2 , some parameters tweaked while sound is playing:
http://www.ucapps.de/mp3/midibox_sid/mbsidv2_drums_bd_examples.mp3
Snare Drum Model #1 and #2 , some parameters tweaked while sound is playing:
http://www.ucapps.de/mp3/midibox_sid/mbsidv2_drums_sd_examples.mp3
Fx Model #1 and #4 , some parameters tweaked while sound is playing:
http://www.ucapps.de/mp3/midibox_sid/mbsidv2_drums_fx_examples.mp3
Now it’s time to check, how drum and bassline sequencer are working together. 
Best Regards, Thorsten.
Hell yes!