Nelson Pass and team uses a pair of Tannoy loudspeakers from the 60’s for their amplifier testing and evaluation. They are very revealing to amplifier changes and tonality according to Nelson.
Tannoy is not the most transparent nor is Pass electronics. Tannoy is not that linear either. But I guess amp designers have their own individual testing style. I like vintage tannoy though and was planning to go to the west coast to listen to that Westminster earlier, but now with lock down don't know when. The system sounds delightful from descriptions and a brief video that Ron had posted some months back. I can see why his reviewer friend, used to Wilson, liked tannoy so much. Will be a welcome change from "hifi" land to music land