Thereafter only real-time clock messages need to be sent to advance the song position one tick at a time.
[2][3] If the resolution is too low (too few PPQN), the performance recorded into the sequencer may sound artificial (being quantised by the pulse rate), losing all the subtle variations in timing that give the music a "human" feeling.
Purposefully quantised music can have resolutions as low as 24 (the standard for Sync24 and MIDI, which allows triplets, and swinging by counting alternate numbers of clock ticks) or even 4 PPQN (which has only one clock pulse per 16th note).
At the other end of the spectrum, modern computer-based MIDI sequencers designed to capture more nuance may use 960 PPQN and beyond.
The resulting PPQN per MIDI-Clock is thus related to the TimeBase in Microseconds defined as 60.000.000 / MicroTempo = Beats per minute.