Hardware Reviews

Acoustic Energy AE509


I have happy memories of Acoustic Energy from its inception back in 1987 and the AE1 mini monitors which founder Steve Tayler brought to me as a young, enthusiastic reviewer. It was a product that quickly became iconic. He was an Ealing neighbour of Virgin’s Richard Branson and I soon found myself helping the airline magnate with advice on antenna arrays to achieve noise-free reception of BBC Radio 3 on his Quad system.

My enthusiasm for Acoustic Energy has not waned and it was with excitement that I unpacked the AE509 floorstanders from a brand that returned to British ownership three years ago. Described as ‘compact’ they are no lightweights, at 22kg per speaker. They are of a slimline design with a condensed footprint and narrow baffle as is the current vogue. As with the AE500 standmount, we are treated to the newly-developed carbon fibre drive units.  


Installation proved simple using the single pair of binding posts and a quick connection to the Hegel H190 amplifier/streamer. Positioning proved more involved and it was some while before I was happy with the placement. In my listening environment ideal siting was with no toe-in (to avoid pronounced HF) and the speakers slightly wider apart than for my usual stand-mount monitors, but closer to the rear wall than I was expecting to be possible. Finish options are piano gloss black, piano gloss white or American walnut wood veneer finishes. Solid aluminium base bars are supplied to for a good floor coupling and these were soon fitted to give maximum stability.

While I remembered AE’s trademark as those aluminium drive units, that’s all changed here: in the 500 range we have new carbon-fibre cones and a dome. Over the years I have heard similar-looking drivers from the likes of Sony and Audax to good effect because it is a far lighter material than many others selected for transducer radiation. In the AE509 we have a two-way design using twin custom-designed 125mm carbon-fibre mid/bass units (in cast aluminium baskets, with metal dust caps and a 35mm voice coil) working together in a D’Appolito arrangement, with a bespoke dome tweeter of the same material. Designer Mat Spandl is delighted because they are less power-hungry than the metal variants while offering better transient speed and offering tonal consistency across the frequency range, not least because of the material’s natural self-damping. 


I was trying to recall when I had previously seen carbon-fibre used for a dome tweeter; it is rare. This 25mm unit replaces the heavier metal dome used on the speaker’s predecessor. A new cast aluminium WDT waveguide on the high frequency driver is positioned close to the mid/bass drivers for optimum dispersion and is extremely stiff to reduce vibration being passed to the tweeter. Careful attention has been paid to the crossover which uses high-voltage polypropylene film-wound capacitors and air-core inductors at critical locations. The 18mm MDF rear-ported cabinet features AE’s Resonance Suppression Composite damping (evolved from the firm’s Reference Series) although the switch to carbon fibre means that the enclosure does not require as much and makes it easier to generate a faster sound with less energy stored. The quoted frequency range is 32Hz to 28kHz (+/- 6dB) which appeared a tad optimistic given the cabinet size. Nominal impedance is at 6 Ohms with peak power handling given as 175W. 

Sound quality
From the off it was clear that, whereas with my BBC-style monitors it’s all about the midrange, with the AE509 it’s pretty much all about the bass. Despite being a bass-reflex design, the slotted rear-port (almost at the top of the baffle) appears to radiate less rearward energy than expected. This permitted a closer-to-the-wall position than I was expecting. My worst fears, based on previous auditioning of AE products at various hi-fi shows, were of a pronounced, almost harsh HF response and an overall ‘forward’ balance which put performers in the listener’s lap. How wrong could I be?


When comparing this new speaker to previous models, critics might refer to the AE509 as dull. That would be a complete misjudgement. This product in no way creates a sound which can be called veiled or opaque. Thankfully, it just isn’t bright or shrill. As one listener commented, rather than being assaulted and bombarded by the various instruments in a recording, with the AE509 one gets to listen to them placed accurately across the highly-believable soundstage. And I concur: there is much better conveyance of the recording venue’s acoustic across the wide and deep soundstage than I had expected. Thinking that these are really bass-friendly units I began with old favourites from Status Quo, The Police, Madness and Ian Dury. These confirmed my suspicions that here we have a design capable of re-creating deep, sumptuous LF response with impressive bass handling which went lower than I had expected given the speaker’s size. Here is a product for the pace, rhythm and timing fans to really get their teeth into; my foot was tapping involuntarily after just a few bars. 

Moving to female vocalists the AE509 handled the repertoire with aplomb; everything from Jennifer Warnes, Petula Clark, Kate Bush and Jennifer Rush sounding rather fine. Keyboard accompaniment was warm and rich, sonorous even but without harshness from the vocalists, managing to avoid the annoying shrillness produced by some speakers and yet clearly not on the recording itself. Switching to a Decca recording of Coronation Anthems (AAM and New College Choir) featuring a lot of William Boyce and Handel, the subtleties of the compositions came through with poise and delicacy, revealing micro details and bringing a warmth and conviviality to the performance. 


Finally a few blasts of speech recordings I know well and, yet again, the AE509 was unfazed. There was no undue sibilance on Harriet Walter‘s voice (as Harriet Vane) in the BBC Radio recording of Gaudy Night by Dorothy L. Sayers; no difficulties either with chestiness or nasality as David Suchet reads Agatha Christie’s Problem at Sea on CD. Using these speakers as my main TV monitors for several weeks, they created a most realistic sound with a deep and wide soundstage to bring many dramas and classic situation comedies to life. Likewise, live classical concerts (via a satellite decoder) also brought the recitals to the listening room in a most believable way with excellent neutrality and atmosphere of the venue.  

In the AE509 we have one of the best mid-priced floor-standers around. They offer not only impressive sonic performance and build quality but also astonishing value for money with a three-year guarantee for the ‘just in case’. These are great all-rounders, as happy with speech recordings as with orchestral pieces, baroque as with solo instruments, rock as with pop. This design possesses a meatier bass than its rivals and is worthy of a personal audition to satisfy medium to large room requirements. AE have achieved excellent driver integration here to produce a foot-tapping sound with transient speed which its rivals will jealously admire. I am looking forward to other AE models in a similar vein in the months and years to come. Here is a model that should be on any serious audiophile’s shortlist. 


Type 2-way reflex loaded floorstanding loudspeaker
Mid/bass drive units: 2x 125mm carbon fibre cone
Tweeter:  25mm carbon fibre dome
Frequency Range:  32Hz – 28kHz (+/- 6dB)
Sensitivity: 89dB
Peak SPL: 115dB
Power Handling: 175W rms
Crossover Frequency: 2.9kHz 
Impedance: 6W
Grilles: slim, cloth magnetic fit
Dimensions (HxWxD, exc. spikes): 1000 x 185 x 270mm
Weight: 22kg
Finishes: Piano Gloss White, Piano Gloss Black and American Walnut wood veneer
Warranty: 3 years

Price when tested:
Manufacturer Details:

Acoustic Energy Ltd 
T +44 (0)1285 654432


Floorstanding loudspeakers


Trevor Butler

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