REL T/5x 8-Inch Powered Subwoofer – Compact Sealed Design with Class AB Amplifier, RCA Inputs, and Powerful Bass for HiFi Stereo Systems, Home Theater, and Surround Sound – High Gloss Black Finish

I have been in audio for the better part of 50 years. I now have experienced something I thought I never would. Seemless integration of a sub into my 10x11x8 room with performances heard in the recorded acoustic space vs coming from boxes in a room. The sub choser matched the T/5X to my Focal 906's and room size spot on. Placement turned out to be centerish due to a room mode from either corner as it is sparesly furnished only having a back wall treatment. REL says to start in the corner and go from there. I tried the Tzero MkIII to get a taste of REL but it simply didn't have the output. Return was easy and unquestioned. With the T/5X using high level connection I followed the break-in video and yep, performance improved, volume went up so I turned it down, 15 +/- 3 clicks up on the crossover and the volume, just like their video said most users end up at. It is set on carpet, no isolators, no messing with their calculated clearance and..the floor literaly moves in waves when material calls it out rather than emphasize it to my ears. Sub bass within limits from an 8" properly designed piece. I love that experience. Vintage system is Akai Tape deck, Rega Saturn CD player, Sonic Frontiers SFL-1 Preamp, Conrad Johnson Premier 11A with Teflon Caps, Nordost Blue Heaven ribbon interconnects, Cardas Quadlink 5-C into amp to smooth things out a bit, then Nordost Heimdall 2 ribbon cables to bring it to the Focals bolted to the Aria S900 stands. The class AB amp has large heat sinks that never get too hot even after hours, stays warm in idle but always ready to go. I like all the options I have with this sub, Arrow Wireless port, High Level and .1LFE option combined if I move it to the movie system, excellent informational vidoes on their web site. Only thing, has no standby switch and the back light is too bright for me but soothingly colored. Fit and finish are flawless, so a beautful addition as well. I plan to try dual T/5X's in the future as properly balanced bass even to 32 Hz is addicting with reproduction felt below that..though have not measured it. I don't want DSP or other electronic aids in the signal path, neither does REL if it is engineered right from the beginning as they have done with this new product to my ears, in this room.

I have a pair of vintage AR M1 Holographic speakers, which is a high end bookshelf speaker. I was told years ago by an audiophile friend that they need a subwoofer to really sound right. Finally I did some research on quality subwoofers and decided on the REL T5/x for my medium sized living room. It really completes the sound and makes those speakers sound great. It’s not set to thump like an obnoxious car stereo, just to create a full, lush sound. I couldn’t be happier with this choice of subwoofer. It’s very clean, precise and musical. It helps bring the whole sound to life - not just the low end - like it adds dimension to toms in a drum set, fullness to brass and reeds, overtones of a piano, overall imaging. My stereo went from pretty nice to YEAH! Definitely recommended!

This replaced a broken Velodyne MiniVee, and so far I’ve been very pleased with it. Excellent sound quality, and connecting the high level inputs was a breeze. I especially like how much information REL publishes on YouTube to determine which product will work best, and then once you’ve bought it, how to install and set it up. Their customer support is top tier (hi, Dermot!).

High quality build and the bass is sweet! No issues at all. Fills my 22x26 living room with excellent bass

You may have heard REL talk about their 8ms filter. I suspect they're using FIR filters to time-align (and EQ) their subwoofer. This is all well and good, and indeed the group delay of a sub can make it challenging to integrate. Unless you locate the sub right next to the listener, and your mains are at least 8ms farther away than the sub, youll get a bit of time distortion. Whether this is audible is another question, and how good it'd sound with treatment is another. I ended up returning as without treatment a sub is an uphill battle, integration aside. Great build quality. Very powerful sub. Doesn't go as low as the Rythmiks and doesn't have their adjustable phase knob, but again the REL will be more time-aligned (despite the 8ms group delay).

I have dual T5x's. Based on recommendations that this would not be powerful enough. Let me be the first to say, this is as much as any 10" I have heard. I am not disappointed with the dual setup, but I could have easily used just one. The unique way the REL's aquire the signal is also very good. It really helps blend the low end into the music. Also, it helps with voicing. I have an amp that is not too heavy on bass. Vs another that is heavy. The special REL cable allows me to capture that voicing. So many other subs are boomy, this one is tight and accurate. The dials are also indexed so little changes can be made accurately. I looked at other brands that have apps and such, but really once the subs are set I almost never touch them. So on the fly adjustment was not that important to me

I looked on the Internet and found many other reviewers with the same exact complaint unit does power is on and has the faintest ever output, but there’s something clearly wrong with it. Having been an audio for several decades and having owned near half a dozen subwoofers, I tried it with different cables on two different systems and got the same result went on the Internet and found many other people are having the same problem Buyer beware

Very nice sub. It was easy to to setup. Liked it so much, I got it's mate. Dual subs is the way.