They stack on top of each other nicely to provide an intrusive but highly effective sound system.
They are powered by two professional stereo amplifiers and a dbx electronic crossover set at 240 Hz. Although the full range drivers are limited to about 12 Khz, it is amply sufficient for this application. The sound of the guitar was reflecting the perturbations of the top end of the speakers and could be improved by using a few 19mm VIFA tweeters on a LR2 passive crossover
So, Paul has managed to design a very good system, with enough portability and performance for his application, at a reasonable cost. Well done!