Glenn Miller august 5: Free music = communication?

This evening I visited Glenn Miller Café and heard some very good musicians:
Fred Lonberg-Holm cello, Raymond Strid drums, Patric Thorman bass and David Stackenäs guitar.

The last set was, as far as I could understand a free improvisation and while listening I wondered about the communication within the band.

My impression was that what looked like a quartet of musicians communicating very intensly was actually four musicians using various technical devices that they had created and practised individually, that matched the technical devices that the other musicians were employing so that you get the impression that there is a lot of interplay going on, whereas actually each musician is playing something that fits in the general soundscape. When somebody changes the music through switching his technical device, the other musicians quickly adapt to the change of scenery by finding something that fits with the new approach.

It's all very accomplished and musical, but is it really communication?