Piano Forum

Since the sheet music is posted above in this thread, I programmed a MIDI performance of the first 12 bars of Tango? by Nancarrow. It's here.
There is no overall tempo marking, but I chose 90,60,75 quarter notes per second.

The multiple time signatures are unusual, but, once heard, the rhythm isn't that complicated. A way  to figure it is to realize that the 3, 4, and 5 beats per measure in each of the staves have to be played in the same interval of time. It's similar to a triplet, except that instead of playing 3 notes in the time of 2, you're playing 5 beats worth of notes in the time of 3 beats, etc.

A more technical consideration in the arithmetic is that the amount of time required to play a measure in the top stave and its pitch is unchanged if the time signature is set to 6/8 and the tempo, in beats per minute, for that stave is doubled. (The tempo remains unchanged as quater notes per second.) Then the three staves all have the eighth note getting a beat. It also accounts for why the tempo in the lower staves in qps is numerically smaller than that for the top stave, even though the top stave, formally, has 3 beats per measure, while the lower two have 4 and 5.

It's also possible that the score might have been simplified a bit. One can get the top two staves to the 6/8 time signature by multiplying the t.s of the uppermost stave by 2/2 and then dotting every mark in the middle stave. Had this been done, it would have been possible to combine the two staves, although two voices would be used. The 5/8 stave isn't easily altered to 6/8 time because the fraction 6/5 isn't simply represented by combining inverse powers of two. So you would still have to play five beats in the time for six. Or if you chose the bottom stave for the root tempo, somewhat like a 6:5 tuple.

Although rhythmically involved, this piece might be played by ear. Otherwise there seems little in the way of melody, harmony, or other musical elements.

Regards,
Jim Ritchie