The Turbo Phase Device that Changed the Industry

Tony Andrews’ involvement with the Glastonbury Festival led to the development of the Festival System, which consisted of separate bass, mid, and HF cabinets. It already contained the second generation of the “Turbo” phase device, the distinctive, slender missile nose-cone shaped contrivances mounted directly in front of the midrange cone drivers and projecting almost the full length of the enclosing horn.

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The Festival System – chunks of which are still working to this day – was a revelation in the mid-70’s concert / festival world of enormous black bins, horns and “Phillishaves”, and the distorted, highly coloured sound associated with them.

The first Turbo phase device goes back to 1973 when it was used with 12-inch drivers, and at that time the possibilities of anything other than a cardboard tube device had not been explored.


The concept was to build a system like a multi-cell horn but with every cell powered. The discovery that the system proved too loud for smaller gigs prompted the decision to go into PA manufacturing that eventually led to the TMS-3, with that early Turbo phase device evolving into the TMS-3’s 10- inch midrange.