Cassettes? Most of the time they worked pretty well - although there were some times where the people running the sound systems were confused about what we were doing. The hardest part was having a large set of headphones pretty much duct taped to my head!

Thanks for your interest - although I must admit, it distresses me a bit to hear that I am 'pushing the boundaries'. I would have hoped that this concept would be well developed and mature, and that I am just using something that is readily understood and available.

All the more reason that I need the forum!