James W. Morris wrote: true, from my experience. unless you want to code event-generating algorithms that rely on bar/beat/tick notation. a good resource is probably the standard MIDI file spec; i guess most sequencers still work with the scheme described therein. lots of open-source MIDI file players and sequencers out there, too. on a sidenote: usually, a 'beat' equals a 1/4 note and has a 'value' (to use your term) that is divisible by both 3 and 4. if using integer 'values' (the unit of which is usually called a 'tick') this allows for precise notation of triplets and even beats alike. for instance: 1/4 note = 12 ticks; 1/8 note = 6 ticks; 1/8 triplet = 4 ticks etc. getting the length of a bar then is as simple as you think. if 1/4 has 12 ticks, a 3/4 measure is 3 * 12 ticks, a 7/8 is 7 * 6 ticks etc. to get the bar/beat/tick notation at an arbitrary point in a song containing time signature changes, you need to iterate all prior signatures (yes, caching b/b/t for every signature change 'event' is a good idea if you need this often). expressing tempo as quarter notes per minute (bpm) [or ticks per second for ease of computation] regardless of time signature is the simplest way, with no obvious drawbacks. as you assume, this allows the sequencer engine to run without looking at time signature. i remember that cubase's 'snap' behaviour was irritating when it had to deal with odd time signatures (back when i used it, years ago, on an atari st). i can very well imagine it still is. tim