I could argue that the decline of Tangerine Dream coincided with the departure of Peter Baumann, the subsequent recruitment of Johannes Schmoellling, and the resultant dominance of Edgar Froese as captain of the ship, but equally the switch from unpredictable analogue to sterile FM synthesis also signalled the demise of a once great cosmic force... but they did have their odd moments in the 80s...
one such moment - admittedly while I was on LSD... I was sat in a pitch black room with one wall drilled through with equally spaced holes admitting the luminescence of a bare light bulb from the adjoining room...
Tangerine Dream - Tangram
pinpoints of light filtering through the penny sized holes in the wall, pulsing in perfect sync to the sequences, one of the greatest lightshows I have ever witnessed, thanks to the powerful magick of lysergic acid diethylamide coupled with the majesty of Tangerine Dream