Saturday
Oct182008

Roy Johnson: Achievements in Sound Reproduction

Home > About > Our Designer: Biography - Achievements in Sound Reproduction

Evolution

For the love of hearing it all

Roy Johnson's improvements in loudspeaker design appear in bold when first employed.

 

Type 4732

1982.

Time-coherent Type 4732 debuts with a solid oak pyramid-shaped cabinet; a non-resonant, foam mounting panel molded for the three upper drivers; and a down-firing, 13" woofer, slot-loaded by an acoustically-treated floor-plate. Why the name? "I went through four of the world's best woofers, seven midranges, three tweeters, and two super-tweeters before I was satisfied," Johnson said.

..................................................................................................................................................

Imago I, II

1991.

Imago: Features an Anechoic Transmission Line (ATL) cabinet for the woofer; exponentially-flared transmission-line behind the tweeter's dome to dissipate rear waves for more natural treble; and an isolated, double-walled cabinet construction to decrease resonances.

It also includes a non-resonant cast marble faceplate with acoustic foam over it to reduce reflections; first-order crossovers placed outboard to isolate vibrations; Balanced-Phase™ circuit design to reduce amplifier distortion, and Crossover Adjustment Modules™ for fine-tuning the tone balance without switches or knobs.

Sound dispersion decreases smoothly from completely omni-directional in the low bass to perfectly directional at the highest frequencies; named Frequency-Selective Dispersion™.

 

..................................................................................................................................................

Diamante

1992.

Diamante: Features and all cast marble cabinet that increases rigidity and decreases resonances; a minimal shape that reduces exterior reflections; a cast marble base that conceals the ATL (similar to Imago's ATL), Crossover Adjustment Modules™. Uses Imago's midrange driver, and the 8" version of Imago's 10" woofer.

 

..................................................................................................................................................

Continuum 1

1995-96.

Continuum 1:  Our lowerst-price three way. The separate cast-marble housing around the midrange and tweeter allows an owner to adjust the soundfield delivery in any room -- named Soundfield Convergence™. Essentially, one adjusts the positions of the upper drivers so their sounds reach your ear when the woofers do. The adjustability means the speakers can be set for a tall chair, or one low, and also near or far away. Rubber and foam suspension isolates this upper section from woofer vibration. A Golden-Ratio Baffle™ inside the woofer cabinet makes the enclosure extremely quiet with no more need for the complex ATL-design found in Diamante and Imago.

 

Top

 

12-inch Subwoofer

1997.

Subwoofers: Develops new measurement techniques that more accurately reflect a subwoofer's performance. The new 12" subwoofer features a Golden-Ratio Baffle™ and 4" Aeroport. The 12SW has a dead-flat response from 200Hz to below 35Hz, +/- 1dB even at super-loud outputs, unlike most every other subwoofer design. The side-exit for its Aeroport keeps that opening away from the direct-pressure field of the woofer, and vice-versa, so each operates into the room at peak efficiency. 90dB sensitivity.

 

..................................................................................................................................................

15-inch Subwoofer

1997.

A new 15" subwoofer employs unique anti-shear vibration feet; two Golden-Ratio Baffles™, and twin 6" Aeroports. Ports exit one on each side, near the back edges. Shown here in lacquered cherry veneer. Flat to below 32Hz, and again, with 90dB sensitivity.

..................................................................................................................................................

Continuum 0.5

1998.

Continuum 0.5: Our first 2-way model. Very compact with solid hardwood panels isolated with Sorbothane vibration damping material over an underlying cabinet of Baltic plywood, MDF and cabinet-grade particle board, and cast-marble front face. A miniature Golden-Ratio Baffle™ is used inside.

 

..................................................................................................................................................

Continuum 2

1999.

Continuum 2: The midrange and tweeter are mounted in separate cast marble housings, shaped and spaced for the least possible reflection of sound from each other and off the woofer cabinet. The midrange and tweeter housings are isolation-mounted with Sorbothane discs to prevent woofer vibrations from reaching them. The midrange enclosure has a Resistive Vent on the back to prevent any low-frequency midrange-driver resonance which would affect the operation of the crossover.

A fully-adjustable aluminum framework allows owners to adjust the midrange and tweeter positions from front-to-rear and up-and-down. The superstructure is covered in a new grille which curves in three dimensions, so it reflects far less sound from its inside-surface back to the drivers for much less effect on the sound.

A Golden-Ratio Baffle™ is used behind the woofer, with a 4" Aeroport exiting the top panel under the midrange enclosure. This port-location produces maximum low bass pressure and the most uniform bass response in taller-ceiling rooms especially.

 

Top

 

Continuum 2 Center

2000.

Continuum 2 Center Channel: The first such speaker to offer a tightly-controlled radiation pattern at all frequencies. Twin 6.5" woofers flank the same mid and tweeter housings and drivers as used for Continuum 2.

 

..................................................................................................................................................

Continuum 0.5 Center Channel / Shelf

2000.

Continuum 0.5 Center/Shelf: The first loudspeaker specifically designed for shelf-mounting. It has an 'Inverse Acoustic Horn' which surrounds the tweeter to prevent reflections and control dispersion. A Golden-Ratio Baffle™ is located behind the cast marble front face. The top-section of the enclosure comes off to reveal an adjustable-postion tweeter (same as Continuum 2). Neoprene feet reduce shelf vibration.

..................................................................................................................................................

Continuum 1.5

2001.

Continuum 1.5: Features an open-air, cast marble, low-reflection curved sculpture for mid and tweeter. Designer solves complex mathematics that result in a new style of first-order crossover circuit. 10" 3-way, using the latest generation of Imago's mid and Continuum 2's tweeter. Sealed woofer enclosure, as in Continuum 1, with a Golden-Ratio Baffle™ inside. Offered in cherry and other veneers. Very slender, very compact.

 

..................................................................................................................................................

Europa

2001.

Europa: Our first two-way in an all cast marble cabinet. Sold literally 10 tons of them (which is a lot of marble to cast).

 

..................................................................................................................................................

12-inch Subwoofer

2002.

Continuum 12" Subwoofer, Series II: The first such speaker to use external braces for improved rigidity. Sealed enclosure with a Golden-Ratio Baffle™ inside.

..................................................................................................................................................

18-inch Subwoofer

2003.

Continuum 18" Subwoofer: Moving as much air as three 12" woofers, it incorporates two Golden-Ratio Baffles™ and solves cabinet-stress issues with a multiple-layer wood cabinet and hardwood-reinforced base. Sealed enclosure, flat response to below 25Hz. Still 90dB sensitivity, and 115dB+ max output.

 

 

Top

 

Continuum 3

2003.

Continuum 3: Johnson solves mathematics which identifies most-correct cabinet shapes and first applies this new knowledge to a new flagship speaker, the Continuum 3.

It features a composite woofer-cabinet base with top port and Golden-Ratio Baffle™inside;an internally-asymetric midrange enclosure; a midrange-enclosure sound-absorption labyrinth terminated in a Resistive Vent; a new cast marble formula we name Q-Stone™; a compression-damped tweeter chassis; and easier Soundfield Convergence™ (driver-position adjustments).

 

..................................................................................................................................................

Callisto

2004.

Callisto: Features include bottom-firing ports which allow the rest of the cabinet to be shaped using the mathematics first applied to the Continuum 3. Twin bass ports inside act as diffusers to sounds behind the woofer. A base platform is shaped to prevent any resonance between the ports and cabinet bottom and also allows the user to tilt the cabinet to achieve Soundfield Convergence™. An asymetrical internal shape for the cabinet further reduces resonances. The speaker features the improved cast marble recipe named Q-Stone™.

 

..................................................................................................................................................

Calypso

2005.

Calypso: Among its features are an additional muffler for the resistive vent on the back of the midrange enclosure and a base column turned 45 degrees.

 

..................................................................................................................................................

Pico Mideo

2005.

Pico Mideo: Features cast marble housings for their midrange and tweeter which are shaped to direct into acoustic foam traps those sound waves normally sent directly to the sides of the cabinet.

 

..................................................................................................................................................

Eos

2008.

Eos and Eos HD: The bass ports combine into one large port at their intake, responding more efficiently to bass-pressure changes from the woofer and minimizing interior turbulence for more bass impact.

 

 

Top