Este sitio is muy interesante. For those who don't read Spanish - who are also probably annoyed at me for publishing in Spanglish - he first discusses three of the major cajón tones (agudo=high, grave=low, medio=in between, the last of which I had not so far thought of as a distinct tone). He spends the rest of the posting talking about how you should place a microphone for a cajon to emphasize one or the other, and the writer's experience with doing it in different gigs. I was wondering about this very question this morning watching the DVD, although I was not searching for this information. Call it a bit of google serendipity (¿como se dice en español? ¿serendipidad por google?) but it popped up when i was searching for "pollito asado" - the method of playing the low tone with the hand in a cupped position, reminiscent of slapping a breast of chicken on the grill (hence the name, "grilled chicken"). That search also turns up a child's game, so I wonder if that's where los peruanos got the name.
Translation provided by request.