TECHNICAL DETAILS ON REFERENCE MIDWOOFER

The Magnesium Cone

Unlike most other metal cone speakers which could be formed easily by simple stamping, the reference magnesium cone had to be precision die-cast because of its incredible tensile strength. For a fixed cone mass, magnesium can contain more material than most other metals as its specific gravity one of the lowest 1738kg/cu.m, even lower than beryllium, which has a specific gravity of 1840kg/cu.m. This incredibly rigid cone results in amazing transients and very low distortion figures.

The Phase Plug

The prominent bullet shape phase plug is not hollow inside nor made of plastic, it is made of solid core high conductivity aluminum alloy. This results in excellent heat dissipation and cooling to the motor system. Excellent dispersion characteristics is achieved also through the use of this phase plug.

The Motor System

Heavy copper rings are pressed-fit above and below the T-shaped pole piece in the magnet systems which give optimum performance in every voice coil position. This reduces 2nd and 3rd harmonic distortion otherwise caused by flux modulation and eddy currents in the magnet system. The high temperature 39mm voice coil is 14mm in height, making its maximum travel at 19mm peak to peak. Great attention has been given to achieve this amount of excursion and still maintain a shallow mounting depth - 71.5mm!

Measurements

The graph below, left, is the raw (unfiltered) response for the reference woofer; you will find the peak at 4.4 kHz which reflects on this woofer's higher frequency resonance. A simple notch filter that can be found in the reference component set passive crossover will reduce this peak to inaudibility. In an active setup, appropriate crossover frequency and slopes or EQ will do the trick. On your right, the graph shows the distortion curves from 20hz-10khz for the reference midwoofer. This superb measurement is testament of the design excellence of this drive unit.

Frequency Response / Impedance		Harmonic Distortion

Midwoofer Specifications and T/S Parameters

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TECHNICAL DETAILS ON REFERENCE TWEETER

This is an extremely precise and realistic sounding tweeter which blends perfectly with the Seas Reference midwoofer (see system curves below) Despite its small size, air under the cavity of the 19.5mm voice coil is loaded into the optimized rear chamber to achieve a low free-air resonance. The free-air resonance is at 830hz.

A special machined chasis is required for the motor system and dual chambers. The material of choice is an aluminium alloy, selected because of its rigidity and thermal properties. As the picture above shows, greater surface area is achieved when an curved and finned configuration is employed.

All these features contribute to the ability of this tweeter to be crossed lower than conventional tweeters. The resulting reproduction is extremely smooth and relaxed, with absolutely no edgyness or brittleness. The sonic advantage of such a low crossover frequency is less lobbing or phase errors at the crossover region, crucial for pinpoint imaging.

Tweeter Specifications and T/S Parameters