Again, I rephrased the question from my original post.

One of the things that amazes me about the best dance teachers I know is that they seem to do this matching instinctively.  They hear the first bar or two of a song and immediately know which dance(s) to dance.  I imagine “instinct” in this case is some combination of natural talent, many hours of practice and the amount of time that they spend listening to music and thinking about how it fits with dance.

After dancing for 20 years, I have something of this sense myself, but being a techie first and a dancer second I feel compelled to break it down a bit more.

There are two sub-questions here; let’s call them 2a and 2b.

Question 2a: “Does the style of music match the style of dance?” This is very much about the general feel of the music – so salsa music sounds like music that you would want to salsa to and swing music sounds like music that you would want to swing to.  But it’s also about the rhythm.  The most straightforward example of this is Waltz, where the three-count rhythm is very distinctive.  Conveniently, every partner dance that you can dance to three-count rhythm has waltz in its name.  There are more subtle variations on this concept: Cha Cha music has a distinct “4 and 1 (or cha cha cha)” emphasis that makes it feel like a cha cha, mambo music sounds a lot like salsa, but with emphasis on the second beat, and there is something called “Swing Rhythm” that distinguishes swing music from other kinds of music. And the list goes on.  I don’t have a great idea for a tool to help with this, but I’m considering writing a more in-depth series on how this relationship works.  So if you’re interested please let me know and I’ll move that up my to-do list.

Question 2b: “Does the tempo (speed) of the music work for the dance?”   Swing is a great example since there are a whole bunch of different dances that can be danced to music that is in the swing style, but they are each danced at  a different tempo.  For example, West Coast Swing is best danced between 28 and 32 measures per minute (MPM), East Coast Swing between 34 and 36 MPM and Jive between 38 and 44 MPM.  I’m building a web application  that at least partially solves this problem.

With this app. you can count out a few measures by clicking the count button on the first beat of each measure and it will not only show you what the tempo is, but also suggest a number of dances that will “work” for this tempo.  Pretty slick, no?  What would you add to this to make it more useful?