The Westminster Royal SE uses the latest and most refined version of Tannoy’s Dual Concentric™ 15-inch Alcomax 3 drive unit, which incorporates Alnico magnets and a computer designed and manufactured reverse throat high frequency Pepper-Pot Wave Guide™.
I thought I’d add some detail photos of the Westminster so you could get a closer look. I think the drive units are objects of beauty, with their elegant golden Westminster logo on the indigo low frequency driver cones, and their glowing, golden, high frequency Pepper-Pot Wave Guides™ (so named because its interior pattern of openings in the wave guide looks like the openings in a pepper shaker).
Below is a closeup of the Westminster logo on the drive unit.
The last detail photo isn't of the drive unit, but of the treble control for the drive unit. I haven't really experimented with the treble controls much because the Westminster sounded so go set flat that I haven't played with the settings much.