REL Acoustics Serie S2 - £1,000

Adding bass extension to a hi-fi system via a subwoofer is all about subtlety. Lee Dunkley is blown away by REL's latest model

Anyone who thinks of themselves as an audiophile may be more than a little dismayed to see a subwoofer review in these pages, but  there’s a lot to be gained from integrating a subwoofer into a two-channel hi-fi system that stretches beyond the reach of the majority of traditional loudspeakers. Subwoofers have come a long way in recent times, and with careful integration including a sub in your setup can have benefits on other elements of the sound aside from just extending its low-range performance.

REL has been at the top of the subwoofer game since the Welsh company first appeared on the scene with models back in the nineties. It perfectly positioned itself for the home theatre boom, and the growth of the surround sound speaker market, with a range of dedicated subwoofer models that enabled movie fans to unleash multichannel soundtracks in their home.

The newly designed Serie S2 is part of a new range of models that REL calls Sub-Bass Systems, and has been three years in the making. The S2 is the baby of the new range at £1,000. Looking over the neat styling and flexible design it is easy to appreciate where your money is being spent, and it comes with a three-year warranty on parts and labour. The cabinet is constructed from marine ply for better rigidity and superior bracing, and even the solid billeted piece of aluminium on the top face is said to aid the dispersion of unwanted energy from the cabinet.

Available in gloss piano black and white lacquer finishes, removing the front panel grilles reveals the front-firing 250mm long-throw paper mâché driver that is reinforced with a super alloy plate for greater rigidity. It’s driven by a claimed 250W amplifier built by REL, which it says is designed to perfectly match and give the correct power for the relative size of the S2’s cabinet and drivers. Underneath is a 250mm carbon fibre passive driver, and even the shape and height of the feet are designed to optimise performance.

The controls and connections on the rear panel have been simplified for ease of set up, and if you’re not keen on trailing a cable from your amplifier to the sub there’s a wireless receiver already built in. It uses the company’s own Longbow uncompressed audio system to receive signals up to 15m away from the sending unit – available separately for £200. The sender utilises both high-level and LFE (where applicable), and is a simple pairing device with no need for the use of your home network hub, so although I don’t use the S2 in this way it should be straightforward to connect to an amplifier and set up.

Sound quality

Positioning the S2 correctly in the room is without doubt the most important thing to get right. For optimum performance in my listening room I find it works at its best positioned in the corner of the room, placed in fairly close proximity to a pair of Dynaudio X38 floorstanding loudspeakers, and angled so that it fires diagonally down the length of the room. After some fine tuning using the controls on the back with a broad range of musical styles containing natural low bass, I’m ready to rumble.

REL explains that because of the nature of the driver material it uses, it is necessary to spend some time running the unit in before it reaches optimum performance levels. Each model has already spent several hours being run-in before it is sent out, but REL recommends a few additional hours in situ and some reduction of the gain setting once it has had time to fully warm up.

The addition of the S2 into my system is a revelation, and instantly results in more drive and energy to the lowest register. It brings a satisfying smile to my face when listening to Jennifer Warnes’ Ballad of The Runaway Horse, giving the impression of a significantly fuller and larger soundstage, while the double bass that underpins the track sounds even more achingly sad than ever, showing the extent of low bass information I’ve been missing out on.

The inclusion of the REL with the Dynaudio floorstanders doesn’t impact on their performance in any negative way whatsoever – it only appears to enhance their capabilities further and draw attention to the perception of the amount of midband detail. Lorde’s Royals is very well extended and will show off the bass capabilities of any loudspeakers, but by adding in the S2 it’s easy to appreciate just how extended the bass line is, showing off the track’s impressive range and highlighting the quality of the recording.

Nowhere is the inclusion of the REL more effective than with high-resolution material. A 24-bit/ 48kHz version of Jean Michel Jarre’s Oxygene demonstrates just how rich and three-dimensional this track can sound, as the REL opens up its impressive scale and soundstage, breathing new life into the recording made in 1976.


The REL S2 merges beautifully into my system, adding a greater sense of scale and depth to tracks I thought I already knew. With some fine tuning, the S2 is effortlessly unobtrusive and impresses anyone that listens with its pace and insightfulness on recordings old and new. It shows off high-res audio to tremendous effect and will compliment any hi-fi system.

LIKE: Impressive musicality; smooth integration; flexibility
DISLIKE: Slightly high price; the wireless transmitter is a £200 add-on
WE SAY: Adds speed and dynamic energy to any system, and is musically engaging

PRODUCT REL Acoustics Serie S2
TYPE Active sub-bass system
WEIGHT 18.1kg
DIMENSIONS (WxHxD) 349 x 368 x 426mm
• 250mm long-throw active drive
• 250mm passive radiator
•l Class D amplifier
• Claimed power: 250W
TELEPHONE 01656 768777