Last month I told you the story of the upgrade to my own kitchen/diner Hi-Fi, where I replaced my existing REL T7i subwoofer with the latest iteration, the REL T7x, and hinted I’d retask said REL T7i in my home cinema system to augment my centre channel speaker. And here we are…

The REL T7i in the wild — spider plant, model’s own. The granite plinth and IsoAcoustic Gaia III feet are there to isolate the sub from the floor; my media suite is on the first floor of my home, and without them, the ‘tweendeck void and the ground floor resonate like a ship’s hull.

According to REL (who paraphrase Dolby Labs, the creators of the technology we use in our home cinema systems):

“Even with the best will in the world (and gleefully I have installed such systems), it’s a struggle to place five, full-range loudspeakers into a normal domestic environment. AV amp manufacturers realised this quite early on, so include a function that automatically apportions bass frequencies below 80Hz to the subwoofer. The subwoofer also has the role of reproducing the Low Frequency Effects channel of course, so can be overwhelmed with information quite easily as a result.”

According to Dolby, on average, about 85% of all sound in the front of the stage is produced by the centre channel. Once you place a subwoofer to underpin the main left and right speakers (like I have), the going becomes very tough indeed for most centre channel speakers.

REL go on to say:

““Home theatre is only capable of delivering superior performance if a few core tenets are followed scrupulously. Chief among these is the understanding among professionals that all channels within a theatre need to be full range. While Dolby’s original stipulation was a remarkable 20 Hz flat response at an enormously high output level, so much of that range can be delivered at around 25 Hz that for the purposes of all but a professional transfer studio, we believe that figure is sufficient to deliver the full range response that Dolby envisioned. It does so at a price that is thousands of dollars less than if we insist on 20 Hz whilst demanding speed and agility.
It starts with Full Range Sound from all channels. Yes, you understood it correctly, full-range audio from all channels.””

connecting a centre chanel rel subwoofer is pretty straighforward, as you can see. note that both positive cables are attached to the centre positive terminal.

well worth seeking out, if you favour a bass-baritone..

As discussed in last month’s blog, REL subwoofers are designed to sample the output of an amplifier and then reproduce what the speaker cannot. Where the output from the speaker rolls off (my Focal Electra in-walls start rolling off at about 45Hz), the subwoofer is rolled on. By a quirk of fate, the mid-fi electronics companies that dominate the AV marketplace decided to factory-set all their AV receivers to a cliff-edge 80Hz crossover point. That starting point is unnecessarily high for virtually any 2-way speaker that sports a 6.5” (165mm) bass driver – they’d sound terrible with music if they didn’t work below 80Hz. Famous Welsh bass-baritone opera singer Bryn Terfel’s vocal range extends down to around 65Hz (E2). It’s a poor pair of speakers that can’t reproduce a bit of Bryn!

Lightening the load on my main subwoofer (a venerable REL Britannia B3) and removing the need for my AV amp to use up valuable processing power diverting the low frequency component of the centre channel information to it, I wired my T7i to the centre speaker output of my AV amplifier. I reset the centre speaker to Full-Range in the amp’s menu and removed the positive speaker leads from my front L&R and rear L&R speakers (to avoid muddying the waters). Then, running the amp in 5-channel stereo mode, I performed the recommended REL setup sequence. Using a music track with a familiar, repetitive bassline to determine the frequency roll-off and gain (volume) on the back panel of the T7i, it took about ten minutes. I used Track 4 from the movie Sneakers OST.

The eagle-eyed amongst you will have spotted I’ve mounted the T7i on a granite plinth with IsoAcoustic Gaia III feet. My cinema is on the first floor and this helps prevent the floor cassette and ground floor resonating like an empty oil tanker.

there’s no two ways about it, it looks an absolute dog’s breakfast, but this was the best shot i could get. as you can see, only the centre speaker has both terminals in play during calibration.

track 4 from this cd - “cosmo…old friend”. the repetitive deep bass note is very useful indeed.

Once that was done to my satisfaction and, after switching my amp off (professional, see!), I reconnected the leads and dug out one of my favourite AV demo discs — Master and Commander (a row-locking — see what I did there — rollercoaster of a Napoleonic War naval saga starring Russell Crowe & Paul Bettany). I cued up Chapter 2, “A Shape in the Fog,” where the tranquil start to the frigate Surprise crew’s day is rudely interrupted with a Beat to Quarters after the Officer of the Watch thinks he’s seen... a shape in the fog.

The Marines’ desperate drumroll calling the crew to action is thrilling and urgent, the men’s bare feet slapping on the oak decks above our heads are suitably meaty, the cabin resonates with the amplified thuds and then the subtle FX of the wind soughing in the rigging and the men’s hushed breathing as they wait, straining their ears for the enemy and awaiting their captain’s orders. The whole scene prickles with anticipation and the sense that this tiny, isolated community is terribly vulnerable on this huge and hitherto empty sea.

A great movie — “an historically accurate portrayal,” according to Dan Snow, *the History Guy.*

I’m sure you’ll have guessed by now that there’s an engagement with “Bonesapart” complete with rolling broadsides that’ll have you ducking “lest a ball knock you on the head.” Most satisfying!

From Kitchen Companion to Centre Stage

The improvement on the system’s previous performance is expressed in terms of a much greater sense of space and scale. Vocals are clearer and weightier, sure, but the real revelation lies in the textures — those subtle shadings and nuances that give sound its emotional heft. If you’ll indulge me in a wine analogy (and why wouldn’t you?), it’s the difference between Chianti Classico and Brunello di Montalcino. Both are born of Tuscany, both from the same Sangiovese grape, both singing with cherries and chocolate — yet the Brunello brings something extra: depth, elegance, structure, a velvety richness that lingers. Yes, it costs more, but the payoff is a greater emotional connection, a deeper satisfaction. And really, isn’t that what we’re all chasing in this hobby?

So, the journey continues. The T7i, once retired from kitchen duties, has stepped back into the limelight and found its true voice — not merely filling in the bottom end, but bringing cohesion, drama and grace to the centre stage. My home cinema has never sounded better.

Thank you for reading.

Words and images by Adrian, (tea by Nic & Andy) - Audio T Swansea

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