AT-1 Floorstanding Loudspeaker

For most audiophiles, listening to a pair of AT-1’s for the first time on demanding material with extremely low bass is a bit of a shock. Loudspeakers of this modest size with a pair of small 5¼-inch woofer-midrange drivers just “aren’t supposed to do that”—shake the room. But the AT-1’s deliver that kind of impact. Even at moderate levels, there is a degree of bass power combined with acoustic detail rarely experienced in speakers of any size or price. In the case of the AT-1, hearing is believing.

“…was impressed by the speaker’s superbly flat frequency response and surprisingly extended low frequencies.” Stereophile Magazine

AT-2 Bookshelf Loudspeaker

How do you follow up the most highly-reviewed product in your company's history? Introducing the AT-2. The compact AT-2 speaker delivers a level of deep bass not previously thought possible from a "bookshelf"-sized speaker. The AT-2's patented H-PAS bass system (Hybrid Pressure Acceleration System) is the reason.

It combines elements of several speaker technologies--acoustic suspension, bass reflex, inverse horn, and transmission line--in a unique configuration to deliver powerful low-frequency response that breaks the "Iron Law" of loudspeaker acoustics: the notion that you couldn't have deep bass extension, good system sensitivity and reasonable enclosure size all in one design. H-PAS changes all that.

"It’s only February, but I think the AT-2 has a good chance of being the Audiophiliac’s Speaker of the Year for 2012, it’s that good!" The Audiophiliac, CNET

A completely new - and better - way to generate bass

H-PAS does not require the use of special drivers, any kind of on-board electronics or outboard equalization -- it is a purely passive system, completely compatible with all AV receivers and stereo amplifiers.

Employing a unique cabinet design, the elements of the different speaker technologies are cascaded one to another in such a manner as to pressurize and accelerate the very lowest frequency back waves as they travel through the cabinet.

These waves are then radiated into the room through a vent at the lower front of the cabinet. There is an “acoustic crossover” from the vent to the bass drivers and the upper bass and midrange regions are propagated directly from the woofer’s cone.

An important additional feature, integral to the design, is an “acoustic bass trap.” Signals travel through this internal passive resonance/harmonic distortion line filter to further reduce unwanted distortion for clean, tight bass. As a result, the AT-1 delivers extended deep bass with high output levels, and exceptionally low harmonic distortion.

The central tenet of this new design approach is somewhat counterintuitive. Instead of using heavy, low-resonance drivers to achieve low bass, H-PAS utilizes quick, high-resonance bass drivers. The internal matrix of the cabinet takes the backwave of the driver below its resonance and pressurizes and accelerates it before it exits the vent. This acceleration increases the impact of the highly pressurized air flow in the enclosure when it leaves the vent. The result is both extended low bass and greatly improved dynamic range at such lower frequencies. The internal workings of the cabinet (using very specific, mathematically-derived ratios between the various cabinet/driver relationships) are such that the low frequency efficiency of the system actually increases with decreasing frequency—exactly the opposite of conventional system behavior, where output below resonance drops rapidly. H-PAS produces a reciprocal output of the high-resonance drivers’ natural rolloff, yielding flat acoustic response to well below that of conventional designs using like-sized drivers and cabinets.

The use of lighter, higher-resonance woofers also means that the AT-1’s H-PAS system exhibits lightning-fast transient response and incredible bass detail compared to the slower high-mass, low-resonance drivers needed to achieve reasonable deep bass extension in ordinary speakers.

In short, H-PAS technology provides greater extended low frequency range, and/or greater output, with increased dynamic range and impact at those extended low frequencies. It can be scaled to fit many size cabinets, small to large. Higher SPL’s are inherent to the design, as is low distortion, which in turn negates any requirement for costly high-power amplification.