Acoustic Energy Radiance 1 Loudspeaker (TAS 196)

Re-Imagining A Classic

The British speaker manufacturer Acoustic Energy burst onto the audio scene in 1987 with the AE 1. Even after twenty years the AE 1 and AE 2 (released in 1990) still rank among the top two-way monitors available regardless of price or country of origin. Not content to rest on its laurels Acoustic Energy has continued to refine and improve its speaker designs. The Radiance 1 is AE’s latest thinking on affordable high-performance small monitors. The goal was not to push the envelope at the cost-is-no-object state of the art, but to attain a new level of performance at a reasonable price. Considering the condition of the world’s economy, more for less could be the new state of the art for consumer products.

Radiant Technologies

According to Mat Spandl, Acoustic Energy’s head of research and development, AE had two principal design goals: The first was off-axis frequency response that was as near perfect as possible; the second was the lowest distortion within the physical limits of the speaker system. To achieve them AE looked at every component in the Radiance 1 starting with the midrange/woofer. Using a Finite Element Analysis system to model an ideal set of characteristics for its alloy cone driver’s surround, so it would correctly terminate excess energy, AE built and tested many prototype drivers with different blends of rubber surround, dampening, and stiffness. Variations in surround geometry were also tested. The Acoustic Energy design team also decided to reduce the effects of heat build-up in the midrange/woofer driver. As the temperature in voice coils rises, electrical resistance also rises, which changes the sensitivity of the drive unit and alters the intended alignment of the crossover. AE employed a unique twin-winding technique on its midrange/woofer voice coil to double its heat radiation area. In addition, the Radiance midrange/woofer uses a thermally conductive aluminum former to improve heat transfer into the driver’s cone and dustcap.

The Radiance 1’s tweeter uses a completely new iteration of AE’s ring-radiator design. (A ring radiator supports the tweeter’s synthetic silk diaphragm at two pivot points instead of one as with a conventional dome tweeter. With very little unsupported material, there’s less opportunity for the tweeter’s surface to develop non-linear resonances.) A metal ring called the “DXT Acoustic Lens” surrounds the new tweeter, serving as a waveguide to increase the effective size of the tweeter without the negative effects of actually using a physically larger-diameter tweeter. The DXT lens also allows the tweeter to behave as a virtual “point source” because it places the unit some distance behind the front baffle. The tweeter’s radiation pattern is constant across an angle of operation defined by the lens’ angle. This gives the tweeter the same acoustic power response as the midrange/woofer.

For the Radiance 1’s crossover, Acoustic Energy’s designers followed the maxim, “Keep it simple.” Compared with AE’s previous generation of speakers, the Radiance’s crossover has gone from eleven components down to only four, with no resistors whatsoever in the network.

The cabinet is the final part of the Radiance 1’s sonic solution. AE chose curved sides because this reduces acoustic standing waves inside the cabinet, increases the enclosure’s rigidity, and lowers the cabinet’s panel resonances. A rear port was employed to substantially increase the Radiance 1’s bass extension.

The Radiance 1 comes in two real-wood veneer finishes—a light-colored “natural ash” and the almost-black “antique ash.” Internal connections use high-quality OFC copper wire; the enclosure is fitted with two pairs of five-way gold-plated binding posts and bridging connectors for bi-wiring or single-wiring. The speaker grilles have a magnetic attachment system so no holes mar the front of the speaker.

The Radiance 1 is manufactured in Malaysia at the newest factory of Acoustic Energy’s parent company, ProSonic Industries. This is the primary reason for the Radiance 1’s modest price tag.