Was it like this? - http://www.youtube.com/watch?v=EqNSwOw1mywIf so I've heard it before and yes that's the sonic boom. Usually "one pop" is heard but if you slow the sound down you'll hear two very fast ones, similar to the shuttle. First the nose, then the fins ... of these rockets ... But because of the distance most are from you and size ... you'll only hear ONE pop ...
A pop during flight is a sonic-boom ... A pop after the "event" is the chute popping out of the nose cone ... -- ROC-Chat mailing list roc-chat@xxxxxxxxxxxxx //www.freelists.org/list/roc-chat