I basically have the same issue, if I run Spark in any sample rate over 44.1, the Audio is 'accelerated'. I have a quad core amd, 8 gb ram, and a motu ultralite hybrid. This issue forces me to run all other programs (such as Ableton, DeckaDance, Cuemix, and FL Studio) at 44.1 as well, or else the whole system comes crashing down. And yes, I can run Ableton, Spark, Deckadance, automap, cuemix for the Motu, and stanton's scs.3d GUI all at the same time, no problem. If I change Sparks sample rate higher, the audio accelerates and usually the system totally crashes when I try to change the rate back. So obviously I don't do that live ;]. if this issue could be rectified the Spark would totally be worth all the trouble, it'd be a 24 bit drum machine! (which is what I thought I was sold in The first place.)
Love the spark!
Emulate the Dr. 202 in both sample (for authenticity, the 202 was a rompler, I believe)
And analog (to trump the original, obviously.) It'd be the dopest kit on the spark.