Though the REL Tzero MKIII is REL’s new subwoofer, it is really like a pocket battleship, smaller but it packs a cracking punch and paired with a sibling it is twice the crunch. This, then, is a review of two REL Tzero MKIIIs, set up to take the place of my own solo REL T/5i that currently supports my Jern 14DS loudspeakers.


The story goes that Richard E Lord (REL) loved organ music. Organ music, of course, goes low, very low and needs control. To get to the lowest end Richard E Lord, put a bass driver in a cast concrete enclosure to build the bass whilst his wife was away for a week. On her return, Richard’s labours were not appreciated. Lord needed to set about a more subtle solution that eventually gave rise to REL.

In recent years, the sale of REL to some of the directors of US company Sumiko (who used to be the REL USA distributor) around 15 years ago was essentially driven by the need for fundamental investment. This process was about finding a company that understood sound, it was not about Lord making money. The REL Tzero MKIII is a result of this investment.



REL Tzero MKIII underside with the downward-firing cone

The REL Tzero MKIII is billed as their ‘entry level’ piece for a high-level input-based subwoofer. A high-level connection is key to the timing of a subwoofer but it is also essential in capturing the sonic signature of the system you are supporting with the REL. The high-level connector is bare wired to the left/right output speaker terminals of your amplifier and connects to the REL using a Neutrik Speakon connector. The time delay to the subwoofers is vanishingly small at 10msec which is far and away quicker than most other subs, says REL.
The driver in the REL Tzero MKIII features a 165mm long-throw aluminium anodised alloy cone, mounted in a steel chassis, it is downward firing and housed in the familiar heavily lacquered REL cabinet made 83mm thick MDF.

The amplification is 100 W of NextGen Class D power, my T/5i has a Class A/B amplification, as do many others in the REL range.

The REL Tzero MKIII also has a low-level phono style input and a 0.1 level input for a 2.1 TV sound system. Each of these inputs is configurable to the rear with the crossover and volume level controls. There is a phase switch selector which can be configured in the set-up process.


As with most things REL, that I have either seen or touched, the cabinet is engineered with a beautifully finished gloss black or white lacquer (there are at least 8 coats of lacquer, they use a two-pass process). Though diminutive in size at 216 x 241 x 260 mm (W X H X D) and just 6.8 kg in weight the REL Tzero MKIII makes a stunning impact. The REL Tzero MKIII comes with a power cable and a high-level connector in the box.

They are retailing at £399 each on the REL site.



REL Tzero MKIII in white wIth Jern 14DS

I’m listening to a pair of REL Tzero MKIIIs in both the black and white gloss finish. They are connected to the latest Anthem MRX 740 AV amplifier at high level. I have this set up in a medium-sized room (3m x 6m x roughly 4m+ high) that is set up with a projector and an Oppo Blu-ray disc player (BDP-105) as well as a Sky Box and a Bluesound Node 2i. The speakers I am using are the stunning Jern 14 DS that really is essentially designed with a subwoofer in mind. I have also a pair of B&W CM7s.

I have had help setting up the pair of REL Tzero MKIIIs from Rob Hunt, REL’s guru on sound design.

Setting Up the REL

First things first, with my current setup with the Anthem AV and my own REL T/5i supporting the Jern 14s I had the amplifier set thinking there was a subwoofer connected to the output terminal, this was incorrect because of course, I had the T/5i connected high level. With this setting removed, we were able to install the REL Tzero MKIIIs correctly. Placing them in a corner generates additional gain so putting a subwoofer in the corner was generating about 9db of additional gain from the 2 corner walls and the floor (3db per surface).

Using a track by Jennifer Warnes called Ballad of the Runaway Horse we were able to set the vocal to the centre of Jern speakers, exactly. This centring is something that is often overlooked and is key to the successful integration of the subwoofers. Then, through a process of listening and subjective knob-twiddling the crossover level was established by listening to a track from the Sneakers Soundtrack (track 4) and finding where it had its first impact. The crossover was initially near 60Hz and ended up at near 75Hz on the first sub and the same on the corner sub. The Jern speakers have a stated frequency range of 90Hz-20kHz with a measured sensitivity of 88db and 8 Ohms impedance.

After this process the volume level was adjusted at the back of the subwoofer, again subjectively, to find the right level using the Sneakers track, we ended up with the volume at roughly half. Then it was a question of switching the phase switch to determine the loudest output, which corresponds to the correct phase. In my case, the phase with the higher-level setup ended up being 180 degrees in both subs.

I got from this process, in conversation with Rob, that setup is just a subjective process. Whereas I thought it should be analytical, set the crossover near where your speakers lowest frequency range is and turn it up, so it is not too flabby. I was so wrong, setting up a REL really is feel, and the subwoofer(s) takes the pressure off the main speakers.

Critical Listening


REL Tzero MKIII in black

After setting up the RELs it was time for some fun. I would normally go to the Blade Runner 2049 Soundtrack opening track 2049, wrong again. Rob showed me the power of the subwoofers with subtle tracks like Freya Riding’s acoustic version of Love is Fire (Tidal FLAC, 44.1kHz). In this track you can follow the emotion of the vocal because the speakers are relieved of the pressure of delivering the lower frequencies, allowing them to be released to concentrate on the midrange and treble. The lyric goes ‘If love is a fire, I’ll burn for you’, it is a beautiful realisation when you realise the RELs are guiding you towards the lyrics. The same process happens with Fyfe Dangerfield’s version of Billy Joel’s She’s Always a Woman (Tidal FLAC, 44.1kHz). Newton Faulkner’s version of Massive Attack’s Teardrop (MQA Studio, 44.1kHz) though is where the RELs really start to show off, particularly at 1’36”.

One thing that Jern speakers do particularly well is deliver a clear and defined image if a song is well presented to them. The resolution then becomes the ace in the Jern 14 pack. This means tracks like Diana Krall’s Temptation (MQA Studio 96kHz) become a different proposition completely, Krall’s voice fizzes through the room and the percussion is tight and crisp.

A trickier bass-heavy track is Snakes and Ladders by Joss Stone (Tidal FLAC, 44.1kHz). With this track, there is a long bass note in the beat but with the RELs I noticed that the bass note is fixed in time with the music rather than lingering and merging with the next beat.

Kudos Cardea C10s

Moving the Kudos Cardea C10s in place I was keen to see these premium midrange speakers performing with the RELs. I ran the same process for setting up the subwoofers but ended up with a lower crossover result, but a similar volume. The C10s have a stated frequency range of 40Hz to 30kHz at the same impedance. The result was simply stunning with the clarity and organisation of the C10s shining through with the bass support adding punch and engagement to the same tracks, particularly Newton Faulkner’s version of Teardrop. Of note for me was the performance of these speakers and with the subwoofers at a lower volume. The same feeling of substance and presence is retained.

Knowing the bounce of these speakers it was obviously time for some Electronic Dance Music and some volume. Playing Bonfire by Knife Party (Qobuz 16 bit 44.1kHz) the sound is absolutely thrilling and spectacular. The speed delivered by the RELs matched by the C10s is perfectly in sync, it took me back to dancing endlessly to KLF in the clubs in St Pauls all those years ago in Bristol.

Bowers & Wilkins CM7

I thought I would revive my floorstanding three-way CM7s that have been collecting dust for a while now. They are slightly out of date in the light of recent speaker reviews but nevertheless are perfectly presentable. On a refreshed realignment of the RELs, I was left with the CM7s (freq range 62Hz-22kHz) at a similar volume to the Jerns though I had to adjust the volume down on the subs after a few minutes. The sound was noticeably warmer compared to the Jerns and C10s with the RELs supporting a dominant soundstage. The CM7s feel as if they have had a new lease of life and I am left wondering where these subwoofers have been all my life!


I have always felt a subwoofer points to a deficiency in the main pair of speakers, this, again, is not the case. I feel as if the subwoofer makes speakers more efficient and in the case of these two REL Tzero MKIIIs they are supporting the soundstage handsomely, without becoming too overbearing. With the Jern and particularly the Kudos Cardea C10s I am getting an outstanding audiophile experience. The fact I’m talking mainly about the speakers and not the subwoofer pair says something very interesting about the RELs.

I really enjoyed the Eclipse subwoofer earlier in February this year, it was just too expensive for my wallet but these REL Tzero MKIIIs are a bit more like it. You do wonder to yourself if we should be concentrating on spending our money on the treble/midrange from our speakers and just investing in REL Tzero MKIIIs. Could this signal the death of the floorstander?

Price point
High-Level Connection
Standby Mode
Lacquer finish
Low volume performance
Maybe a third one?


Full details of the Specification are on the company’s site.

1 comment

Add yours
  1. 1

    What was your reason for replacing the T5i with the pair of TZeros? I currently have a single TZero with a pair of B&W CM8. I’m not sure whether I should get another TZero or go for the T5x (the single Tzero sounds great, I’m just curious what a pair or T5x would sound like.).

    Furthermore, can I combine a first gen TZero with the MkIII? (My room is ~24sqm).

+ Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.