The company  (35001 Ltd) was formed in January 1977, after Wm. Wright had left Leigh's sound division (Dayton Wright Associates). Prohibited by the contract he had signed with Leigh, from forming a company either doing R&D on, or manufacturing electrostatic loudspeakers, he turned to cone, horn and dome speakers.

The new company developed several models of bipolar loudspeakers. Special crossovers using constant-impedance phase-shift networks were employed to smooth any phase delay.

Wright had to employ an upward-firing dome tweeter on all the speakers, to aid the ambiance. The two larger speaker systems were built in matched pairs - with  'a left and a right) speaker system being shipped to dealers.

This caused some minor problems as the matched-pairs could be split and sold only as a pair to customers. Although the left and right speakers were clearly marked on the cartons, and the serial number plates and speaker controls were on the opposite sides, a few dealers couldn't seem to cope with this. The same problem seem to confuse some reviewers as well!

Wright's opinion of reviewers suffered when one magazine swapped sides on setting up the speakers, and wrote a bad review commenting on the systems seeming to be 'aimed/firing' well off the central axis between the speakers! When Wright called him, his response was in essence, "I am a stereo expert and I don't have to read manuals to know how to set up  speaker system".

Only the woofer/subwoofer were not bipolar. These relied in the use of SF6 (sulfur hexafluoride) gas (which is inert), to increase the virtual volume of the enclosure. As SF6 is an 'ideal gas', it operates as an 'isothermal' spring, thus avoiding the problems with 'acoustic-suspension' loudspeakers that operated partially as an isothermal and partially as an adiabatic system. Some designers seemed to lave little knowledge of Boyles Law or the Laws of Thermodynamics.

In effect, the use of SF6, increases the virtual volume of the enclosure by a factor of 27! As can be appreciated, this both lowers the distortion as well as permitting a lower resonant frequency of the woofer.

But to use this, a larger cone mass is needed and the suspension has to be much more compliant. This bring up the problem of 'gyratory-moments-of-inerta' if the woofer cone is to remain stable during its excursions. The usual concentration of mass near the voice coil does not accomplish this.

What is needed is to shift the effective cone mass farther away from the cone's center-of-mass. Doing this increases the gyratory-moments-of-inerta and the cone is more stable. Wright used a near-flat plate on the front of the cone - with most of this plate's mass around the rim! He added an EPDM foam-elastomer as a damping element on the front of the disk.

Watson Labs Credo







Watson Division of Dayton Wright Group

Model 15

© 1980, 1999 Wright Electroacoustics


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