I'm writing a piece of electronic music on a Digital Audio Workstation. I'm not sure what you would call the genre - trance, ambient, maybe even electronic jazz. It starts off slow and reflective at about 70 BPM. But after 8 measures I speed it up to 140 and add in a lot of percussion and effects. I don't change the key (f minor). It sounds okay to me but I may be prejudiced 8-).
My question is, are there things I should do to make the transition smooth and not too abrupt sounding to The Listener? One thing I did in this one is in the last measure of the slow part I started introducing shorter notes - it had been mostly quarter notes and half notes but near the end I started introducing eighth notes and even some 16th notes. That seemed to help but are there other things that are done in these situations, for example in chord structure or phrase construction? In some songs I've heard people put in faster percussion during the end of the slow part, often with a rising pitch, to hint to The Listener that it's about to change.