There is a passage in the introduction of Bill Brewster and Frank Broughton’s Last Night A DJ Saved My Life that begs for rumination:
“Where a guitarist can impress an audience by playing a 30-second improvised sequence of chords and notes, what a DJ does takes a lot longer – a DJ needs to be judged on a two or three hour narrative of records”.
Brewster and Broughton are implying is a general relativity of music time. One can get caught up in the semantics, calculating what how many minutes of an opera amount to a whole jazz concert. That is not important.
A minute could be recitative that sets up an aria in opera or could be an entire hardcore song. An hour could be half way into a DJ’s set at a night club or could be an entire set for a rock band. Eighteen hours could be your entire music catalog on your computer or could be one song: Erik Satie’s “Vexations” played as written with eight hundred and forty repetitions.
Time is the material from which all music is made of. All music experiences, however, use time in different ways and however they please. That is the freedom this relativity grants us. It is not for no reason that Stravinsky professed that music is a reflection of man’s relationship with time.