Polyrhythms

I have recently been finding myself listening to many different African (and some cuban) percussion artists, and I continually keep hearing them talking about polyrhythms.

To the best of my hearing, all I can make out as to what they're talking about is that sometimes it seems like there's two different time signatures going at the same time

Am I right on this? And if not then what the heck is a polyrhythm?

Polyrhythms and polymeters are different

Polymeter you can find in, say, Stravinsky's Petroushka. There's a point in the ballet (I forget where) where 7/8 is played over 4/4 I believe. Two different and simultaneous acting meters, that's polymeter.

Polyrhythms doesn't involve actual time signature changes, but superimposed rhythms over the normal heirarchy. For instance, if you have constant eighth notes in 4/4, but you imply another eighth note pattern of 5/4 over that. Or for a more obvious example, quintuplets over triplets. Those are polyrhythms, just ask any percussionist friend you know about those. Don't ask them to demonstrate 7:9 for you though, they might get mad.

Yeah, it's just having hits every certain number of notes, with two different numbers. For example, 5:4 has one part playing every five subdivisions, and one part playing every four (or something like that--it doesn't have to be that exact). Dig:

1+*+2+*+3+*+4+*+1+*+2+*+3+*+4+*+1+*+2+*+3+*+4+*+1+*+2+*+3+*+4+*+1+*+2+*+3+*+4+*+1
x---x---x---x---x---x---x---x---x---x---x---x---x---x---x---x---x---x---x---x---x
x----x----x----x----x----x----x----x----x----x----x----x----x----x----x----x----x

1+*+ = 1 e and uh.

Two against three, or simultaneous hemiola, is generally considered the easiest polyrhythm. Try it.

When its comes to Polyrhythms of African music, Caribbean and some Latin American music that use African derived rhythmic concepts of polyrhythm you can either be talking about having two seperate time signatures occuring at the same time or having multiple layers of rhythmic patterns. These patterns are mainly based on short and long stresses.
Its not quite the same as saying 2 against 3 or 3 against 4 although you do get those types of examples in combination with my above statement in African, Afro-Caribbean and Afro-Latin music.

Here are some examples of polyrhythms, if your confused. The first measure is how they look seperately; the second shows the length of the actual notes when the rhythms are played together.

You may need to increase the tempo to make sense of some of the more complex polyrhythms, such as 4:5.

triplets with one hand, eighth notes with the other (for example)

Originally Posted by Fermion

Here are some examples of polyrhythms, if your confused. The first measure is how they look seperately; the second shows the length of the actual notes when the rhythms are played together.

You may need to increase the tempo to make sense of some of the more complex polyrhythms, such as 4:5.

His confused what?

I actually use polyrhythms extensively in many of my works, but sometimes you have to know where to look. Oddly, both works I've posted as complete don't have a scrap of it.