A flagship model from a well-respected British manufacturer is always noteworthy. It becomes even more intriguing when the developers opt to break away from conventional approaches and explore innovative alternatives. In the Acoustic Energy AE509 two-way systems, all drivers, including the tweeter, are constructed from carbon. This lightweight and robust material, known for its excellent damping characteristics, is expected to deliver a fast and detailed sound. While this is the theoretical expectation, how does it perform in real-world scenarios?
The development of a higher-class audio system led to a strategic decision to depart from the traditional 2.5-band configuration in favor of a “pure” two-band design, which is more commonly associated with shelf monitors. This approach aimed to enhance the time alignment of the frequency ranges, achieved in part by simplifying the crossover networks. The lower and mid frequencies are handled by a pair of 125-mm drivers arranged in an MTM (Midrange-Tweeter-Midrange) layout, complemented by a one-inch tweeter, following the classic d’Appolito design. This configuration is recognized for its broad directivity and improved phase coherence between the frequency bands.
Another notable innovation in the Acoustic Energy AE509 is the use of carbon for all drivers, including the tweeter. Carbon fiber cones are less reactive than those made from aluminum or ceramics, which, according to the developers, results in a more natural and clearer sound. Based on my experience, carbon’s lower inertia allows it to convey sound nuances more effectively and provides a smoother character compared to aluminum. The midbass drivers in the Acoustic Energy AE509 utilize a bass reflex design, enabling a lower frequency response down to approximately 32 Hz. The tweeter, featuring a substantial relief suspension, is housed in a short waveguide known as WDT (Wide Dispersion Technology), designed to broaden the directivity pattern. The carbon dome tweeter operates efficiently up to 28,000 Hz.
The case design closely resembles that of the Acoustic Energy AE309, featuring a slim front panel and elevated drivers. However, the new flagship models lack a compartment for ballast, relying instead on an increased case mass to minimize resonance, achieved through an additional layer of a rubber-based material. As a result, each speaker weighs a substantial 22 kg, even without the addition of sand or metal shavings.
Another notable innovation is the unique approach to mitigating standing waves. Tall and narrow enclosures often behave like organ pipes, resonating at specific frequencies that can interfere with sound quality. Traditionally, this issue is addressed by incorporating internal partitions or labyrinth structures. In contrast, Acoustic Energy has integrated a Helmholtz resonator within the case—a chamber with an opening specifically tuned to counteract the fundamental frequency of the standing wave. While the effectiveness of this method remains to be assessed.
The base of the Acoustic Energy AE509 case is constructed from metal, featuring semicircular protrusions equipped with threads for high spikes and lock nuts. The speaker grills are magnetically attached, and the speakers are offered in black or white lacquer finishes, as well as in natural American walnut veneer.
In comparison to the AE309, the latest flagship models exhibit a heightened sensitivity to subtle details, particularly in the upper midrange and treble frequencies. Carbon domes effectively dissect the audio spectrum into its individual elements, doing so in a manner that is both unobtrusive and harmonious, rather than overly technical, thereby respecting the integrity of the music. This characteristic extends to the midrange as well—on high-quality recordings, these speakers can unveil surprises, highlighting previously overlooked tonal and performance subtleties. This is particularly noticeable in orchestral compositions and large jazz ensembles, where the expansive soundstage is complemented by a rich array of tonal variations.
Reflecting on earlier terminology, the British Acoustic Energy AE509 models have evolved from their more restrained predecessors; they now embrace contemporary genres and appeal to the modern listener. Nevertheless, their foundational strength lies in the ability to reveal the full spectrum of music without imposing any artificial enhancements, a quality that is deeply rooted in their distinguished heritage, yet expressed at a new evolutionary stage.
Acoustic Energy 509 Specifications
- Configuration: 3 drivers, 2 bands
- Acoustic design: bass reflex
- Frequency range: 32 — 28000 Hz (+/- 6 dB)
- Nominal impedance: 6 Ohm
- Band crossover frequency: 2900 Hz
- Sensitivity: 89 dB
- Peak sound pressure: 115 dB
- Maximum input power: 175 W
- Finish: black and white lacquer, natural American walnut veneer
- Dimensions: 1000 x 185 x 270 mm
- Weight of 1 pc.: 22 kg
