In the video you can see the 8-channel speaker setup that often is required to perform some works by The DK<projection>. It is used a combination of two sets of four speakers each, one at the top level and the other at the bottom level. From the top-view, all together conform a kind of eight-pointed star. Turn on your speakers and let it go for a while.
Two stereo lines [L/R] accompany the 8-channel speaker surrounding set. Generally the stereo lines work as amplifiers of non-processed signals that come from the acoustical sources, as while as the surrounding lines output the processed signals. Two subwoofers support the two stereo cabinets; this pair of low-frequency speakers does not output the amplified acoustical sources signal, but only the processed signals.
In this last post, it is described a real situation for Extrusion, a 8-channel tape:
Here you can see some still images of the set representation: