Tannoy writes: "We love these old Tannoy product brochures, the unique attributes of our legendary and exclusive Tannoy Dual Concentric™ driver units are still true to this very day. The main benefit of Tannoy’s Dual Concentric™ design is that it performs as a near-perfect point-source, with the full-frequency sound emanating from a single spot. This approach eliminates the phase shifts that all conventional multi-driver speaker systems suffer from, preserving the tonal character and harmonic structure of program material as no discrete-driver system can."