Rogers AB3a Subwoofer

hfncommendedSince its birth, devotees of the LS3/5A have craved more bass – does the answer lie in Rogers' active AB3a sub?

Delayed because of the pandemic, Rogers' AB3a subwoofer is one year off being able to claim it's the 25th anniversary celebration of its passive predecessor, 1995's AB1. Yes, the gap between them has been that long. The postponement doesn't, however, diminish the delight LS3/5A users will show for the arrival of a dedicated active subwoofer for one of the most celebrated small monitors in the history of hi-fi. It's here, and it's a honey.

Given that current Rogers or Falcon Acoustics LS3/5As [HFN Jul '19 and Dec '18] sell for circa-£2500 per pair depending on finish, while vintage LS3/5As can fetch as high as £10,000-£15,000 if you're either obscenely profligate or certifiably insane, the £3499-per-pair sticker price of the AB3a will hardly cause outrage. What's decided for you is the finish: as standard it's only offered in satin black, a colour which works with whatever LS3/5A you perch on top. Rogers will, though, finish a pair any way you like for an added stipend.

Double Bass
What you get are sized exactly like the AB3a's quarter-century-old antecedent, but the rear-firing driver count has doubled, each cabinet now hosts a 50W amplifier, and the look is vastly more refined. The slick cabinet just happens to raise the LS3/5A to what I've always found to be the perfect height, so in situ, each AB3a-plus-LS3/5A stands 3ft/920mm tall, give or take a few millimetres depending on how you adjust the spikes.


The AB3a’s robust black 12mm birch-play cabinet is supported on an MDF plinth with threaded inserts for the supplied M6 spikes. Top dimensions perfectly match the LS3/5A although other mini monitors can be used

Contrary to discussing these vis-à-vis LS3/5As, it's worth pointing out that Rogers describes these 2ft-tall units as 'specifically designed for use with the LS3/5A or similar small monitors'. It's a claim supported by the AB3a's super-flexible adjustments, which I'll get to in a moment.

At the back of each AB3a, beneath a Tygan grille held in place magnetically, are two woofers like the 're-imagined' B110s in Rogers' current LS3/5As. The enclosure is sealed, whereas the original AB1 was ported. Below the woofers can be found four rotaries for adjusting the phase (0° -180° ), high- and low-level gain and low-pass filter frequency (40Hz-240Hz).

These steps are undertaken by ear, but the manual is lucid, so the listener is guided into setting each for peak performance. With judicious listening, some music with clean, rich bass, and a friend to fiddle with the knobs while you sit in the hot seat, you can optimise the low-frequency alignment for ideal room placement. I was lucky as they worked perfectly exactly where I place almost all small, stand-mounted two-way speakers in my room, which happens to be my preferred spot for LS3/5As.

Connections are a different matter. The best set-up for this employs the 'two pairs of leads from one set of terminals' reminiscent of bi-wiring. One goes to the AB3a, connecting via a professional Speakon plug, supplied with the AB3a and 5m of cable. The other, user-provided leads go to the LS3/5A (or other small speaker) from the same set of terminals.

Alternatively, there are also phono inputs to feed the AB3a from a sub or preamp output. This connects to the low-level input, while the Speakon feeds the high-level input. Nevertheless, feeding the LS3/5A and sub from your main amp output remains the preferred method. Niggles? As the on/off rocker is on the back, how about a tiny blue pilot light on the front, at the base, so you know they're switched on?

sqnote Fire Down Below
Feeling mischievous, I turned the AB3as around, the drivers firing at me. And stone me if they didn't sound amazing with a volte face. I accept, though, that this is not advised, but, hey, try and stop me. I'm glad I did. Having said that, for this review the subwoofers were auditioned as designated: rear-facing drivers and with current-production LS3/5A loudspeakers.

Rogers International UK Ltd
Virginia Water, UK
Supplied by: Rogers International UK Ltd
0333 533 0135