But here is a "proof" that beats are perceived as if they were echos, using a rock beat. A (natural) echo is softer than the original, because the sound is traveling a greater distance to get to your ear. So, an artificial echo should also be softer. I used to play drums and I remember instinctively hitting the hi hat like (on quarter notes):
(DAH-Dah)-(Dah-dah)
So the echo pattern would be like
#1 Downbeat
#2 (echo of #1)
#3 (echo of #2)
#4 (echo of #3)OR
#1 Downbeat
#2 (Small echo of #1)
#3 (Big echo of #1)
#4 (Small echo of #3)The way to test a theory of causation is to remove beats and see if it sounds right to your ear. Pay attention to how the transition sounds. Does the transition sound natural? This is kind of hard to do with rock rhythms. The theory becomes more interesting as the rhythms get more complex. When I was thinking about this, I was imagining house music or other electronic dance music.
I don't know much classical music, so I haven't really even thought about it.
That isn't true! Beat #1 can have an infinite number of echos.
N.B.: When I was initially thinking about this I was thinking of subsequent beats as "echos," and I mentioned the echo concept here in the hope that it would be something concrete and instantly relatable. But the echo concept only goes so far, because the "echos" don't have to sound like the original (orig: crash! echo: whistle), and the echos can be removed and replaced over time (say, a change every 4 bars).
The concept of an "echo" is that
1. It comes after the "cause"
2. It's less accentuated
For example, when listening to a rhythm, you construct rules like:
"Boom" comes before "whoosh"
I think it's actually a bit of a trick. It causes the song to sound faster. The reason is because the snare or whatever on #3 is perceived as being incongruously loud, too loud to be an echo. Which gives the impression that it's a second main beat, splitting the measure into two halves and making it sound like 2/4.
Having said that, it might also make sense to consider it an echo of the bass drum. You could remove the snare and leave the bass drum and it would sound ok. If you tried to remove the bass drum and leave snare on #3, it really wouldn't sound right.
This doesn't match the hierarchy of beats present in most music written in 4/4, where beats #1 and #3 are strong beats-- with beat #1 getting a greater emphasis than beat #3-- and beats #2 and #4 being weak beats. Much of the music of the classical period supports this fundamental pattern-- in 4/4 cadential formulae are generally articulated on beat #1 or beat #3, and rarely on beat #2 or #4.
One could make the argument that beat #3 is an echo of #1. But then beat #2 couldn't also be an echo of beat #1. (And there isn't a similar hierarchy of weak beats with #2 and #4.)
Furthermore, this hierarchy usually extends out exponentially in larger durations. So in a Mozart string quartet you'll hear how rhythmic material of measures 1 and 2 is often repeated (or slightly varied) in measures 3 and 4, with measures 2 and 4 being the "weak" measures. A lot of repertoire from the classical period extends at least two levels further so that the first four measures are a group balanced by another group of four. That 8 measure phrase then has a matching 8 measure phrase, although once we get that far out the rhythms aren't usually strictly symmetrical or imitative anymore.
I haven't read the literature but I'd imagine music cognitive research can shed light on just how far out humans can track those rhythmic groups. On the one hand, I know it has to be smaller than, say, an entire section of a sonata (I've never perceived a development section as the "weak" rhythmic group, for example). But techno music makes me speculate that at least in simplistic musical structures these groups can extend quite far.