The REL S/510 subwoofer with stylish front grille

This is a HiFi review of the REL S/510 subwoofer. The first thing to know is that I am a believer in subwoofers, I am an owner of the ‘entry’ REL T/5i that supports the Jern 14 DS speakers I love so much. The Jern speakers were, and are, designed with a subwoofer in mind to take the low-end 20-100Hz range so that the Jern tweeter and midrange can concentrate on the ‘good’ stuff. This does not take anything away from what the subwoofer performs which is, for me, the base layer of music reproduction.

Design

This REL S/510 is a front-firing 10 inch (250mm) active woofer that also features a 12 inch down-firing passive radiator. There is no port in this subwoofer box, this passive radiator design ‘engages the floor’ and eases the air pressures involved. The REL/S510 is driven by a NextGen 3 Class D amplifier with 500W of power output.

The REL badge on the top is a fine tuning point that is individual to each subwoofer cabinet, that’s detail

Input to the REL S/510 can be through a hi-level Neutrik Speakon cable, the best way of using this REL S/510. This method involves directly wiring the input cable to the amplifier terminals, or speaker terminals. There are low-level stereo LFE RCA or LFE XLR inputs too.

Importantly, there are the same outputs available, offering an upgrade path for the bass heads where it is possible to stack two or three of this REL S/510 if the urge, or the room, takes you. It is also possible to set up this subwoofer in a wireless configuration with the REL wireless airship system that is sold separately.

Quality

These REL S/510 boxes are silky and gorgeous, with a 10 coat lacquer, offering an insight into the loving process of building these minimalistic looking boxes. They are very difficult to photograph in black! The REL S/510 has two silver carry handles on either side as it weighs in at 31.7kg.

The REL Dimensions are (w x h x d) 400 x 410 x 464 mm, add 44.5mm in depth when using a hi-level connector. It is about the size of a footstool. The REL S/510 is available in piano black or white. The REL/S510 is priced at £2,299.

Performance

Review Equipment

REL S/510 subwoofer has plenty of room at the back

I’ve been fortunate to have the Kudos Super 20A floorstanding speakers for a few months, they are really special. They have plenty of low end in the right configuration, for example with the Moor Amps Angel 6, but the REL can and does offer more.

I have the REL/S510 wired high level with the supplied cable to the Moor Amps with Tellurium Q speaker cable and XLR from the Moor Amps preamplifier, I’ve been using the iFi Pro iDSD as a source, fixed analogue out, beautiful.

Physically

The REL S/510 has 10 layers of lacquer making it very hard to photograph!

The setup process, for placing the REL S/510, is outlined in the recent review of the pair of REL Tzero MkIIIs. I used the same process and tracks but this REL S/510 seems to be fairly unfussy. You don’t really want to be moving this thing about much, given its weight. Swapping the supplied kettle cable to a Vertere Redline power cable was well worth the time.

Graceland

There is nothing wrong with these Kudos Super 20As, but the REL/S510 really does offer a platform from which their midrange can shine. I happen across Paul Simon’s Graceland (Qobuz, 24-bit, 96kHz) and the introduction after the acapella on Diamonds on the Soles of her Shoes is just one of the best experiences I’ve had with HiFi, it just hits you. Recovering from this track, 5 minutes later Homeless happens, featuring Ladysmith Black Mambazo. Goodness, the breath in the track and the pure voice is a sound to behold at this level; note there are no huge bass lines here it is just the platform that’s created. It is a bit like adding an orchestral arrangement to a demo track.

A switch to a proper bass heavy EDM (Electronic Dance Music) track demonstrates how fast the REL is, for example, Knife Party’s Bonfire kicks off about a minute in and the REL thunders through it, the Super 20As carry the midrange with seeming ease. For a bit of big bass control, it is time for Benson Boone’s Ghost Town (Tidal Masters 24 bit, 44.1kHz). This is a lovely track and the REL just eases the towering bass across the room, creating a whole body experience. I always search for the bass rumble at the end of London Grammar’s Rooting for You (Qobuz, 24 bit, 44.1kHz) and here the bass is long and lingering and very satisfying.

Thoughts

… it is the same as Billy Preston… on The Beatles’ Get Back. He’s just there but making it all just that little bit more amazing without attracting too much attention…

It’s feeling like this REL ‘platform’ is the theme for me, it is the same as Billy Preston turning up to the recordings on The Beatles’ Get Back. He’s just there but making it all just that little bit more amazing without attracting too much attention and enabling the main players to free themselves. This seems to me to be what the REL is doing, just providing that backdrop. I’m listening to Exit Music (For a Film) by Radiohead (Qobuz 24 bit, 96kHz) and this track illustrates how orchestration lifts the performance to a different level.

When I think of significant cable upgrades, power leads for example, and all the other expenses that come with HiFi, it might be that upgrading your system with a subwoofer might be the single most impactful thing you can consider. It also might be, and I’ve said this before, the death of the floorstander. If you think of the saving on a standmount with a subwoofer versus a floorstander, it could be the way forward?

Overall

…a lifetime investment…

I’ve had a few subwoofers and they’re always great. This REL S/510 feels like it has been the smoothest, most impactful one I have heard so far, even above the two REL Tzeros and the Eclipse subwoofer last year. Its ease of setup and unfussy positioning are a highlight and this one feels like a lifetime investment, I really like the idea of an upgrade path, if you want more scale or you move and have a bigger room, you can just buy another one.

Specification

Full details are on the company’s site