There seems to be no difference in tempo between, say quarter note=120and eighth note=240.Why would one change the defining note?It is just a convention...based on key signature...based on the time signature...based on the prevalentnote in the composition???Is this notation used primarily for the musician who'splaying the piece?If my only purpose for creating the piece, is to listen to it from my computer, it seems to make no differencewhat the defining interval is. Is this correct?Thanks for your time.Gordon Isbell
Gordon said: <<<There seems to be no difference in tempo between, say quarter note=120and eighth note=240.>>>
That's correct!
<<<Why would one change the defining note? ...based on the time signature?...based on the prevalent note in the composition???>>>
I don't know for sure, but probably more strictly the first, though I'd feel inclined to use the second reason as well. It is used by composers who want to give a strict tempo for musicians.
<<<If my only purpose for creating the piece, is to listen to it from my computer, it seems to make no difference what the defining interval is. Is this correct?>>>
Correct. It'll make no perceivable difference. (I'm not sure if it alters the timer intervals or whatever, but I expect not). It really is just for the musos so that they don't stuff around with the tempo and do anything too "interpretive".
Regards,
Andrew
From a neophite--
I don't think it is just the time signature, but also the beat pattern. For example, in 6/8 time one would use a quarter note if the music is played with three beats to the bar, but a dotted quarter if it is two beats to the bar. At least, that's what I do. I'm happy to accept corrects from the experts out there.
Cyril N. Alberga
If you have a VERY slow piece in, say, 2/4, the conducter would conduct in 4. If that is the case, the conducter would most likely enjoy the convenience of a tempo marking in the beat they are conducting. Conducters are notorious for not being able to do maths, which explains why they are so lazy, they can't simply double the quarter note tempo marking. :)))
Traditionally, the note used for indicating the tempo is the one that represents one beat. For example, you could have :
3/8 : eight note = 240
2/4 or 4/4 : quarter note = 120
2/2 : half note = 60
6/8 or 12/8 : dotted quarter = 80