Tannoy Westminster 15" Dual Concentric™ driver pair

by kent3888 Sat Jun 10, 2017 4:26 am

Here is a pair of ultra rare top-of-the-line Tannoy Westminster 15" Dual Concentric™ driver pair with production serial number next to each other.

Ronald Rackham developed the Dual Concentric™ speaker in 1948, the Monitor Black, which brilliantly integrated a high-frequency compression horn driver unit into the same axis as a fifteen-inch direct radiating low frequency driver on one chassis. Rackham also designed the Guy R. Fountain (GRF) and Autograph corner horn enclosures for the Dual Concentric™ speakers, which also quickly attained status in the music industry as high-performance designs. If Nobel Prizes were awarded for achievements in audio electronics, then Ronald Rackham would certainly be deserving of one for his contribution of the Dual Concentric™ speaker design—it is a positively brilliant musical device that has been highly revered by generations of music lovers.

The high frequencies (1000Hz to 20000Hz) of the Dual Concentric™ drive unit are provided by a high performance 2-inch compression driver with a wide dynamic range whose acoustic output is routed through a multiple phase compensating device into the throat of a solid steel acoustic horn, where it goes through an impedance transformation that matches the compression driver's radiation to the room. The driver uses a aluminum-magnesium alloy diaphragm that is manufactured according to a precision five-step process that produces a grain structure aligned at the molecular level to provide high performance and long-term durability. The diaphragm is driven by a round wire voice coil that is an ultra-low mass aluminum design, and is wired with copper Litz wire for high performance and long-term durability. The acoustic cavity of the driver is damped to control its response and to match its impedance to the horn throat. The compression driver's response extends two octaves below the crossover frequency of 1000 Hz, which eliminates colorations that can arise due to operation over the fundamental resonance region.

The 15-inch low frequency cone is made of a proprietary paper-pulp material that is treated to absorb internal resonance modes, and utilizes a reinforcing structure that gives it a very high stiffness to mass ratio that allows it to maintain very accurate pistonic motion over its frequency range. The low frequency cone has a damped twin roll fabric surround that is designed to be compliant and linear over the large excursions the driver is capable of. A high power motor that consists of a four-layer coil that is suspended in a very fine tolerance magnetic air gap drives the cone. The coil is wound using a special high temperature adhesive system and then goes through a curing process that ensures reliable operation at high peak power inputs the driver is capable of handling (e.g. 550 watts peak, 135 watts RMS).

Source: http://www.positive-feedback.com/Issue49/tannoy.htm

Comes with a DIY Cabinet that matches perfectly with this driver. Cabinet is huge and heavy, self collect in KL.

Price : SOLD, Thank you Hifi4sale

Contact: 012-6767388