I wanted to jump on here and write a quick review on how great of an experience I have had with Monoprice's customer service. I read that there was sometimes an issue with these subs amplifiers failing and I went ahead and bought it anyway. Well I was one of the lucky ones to also have an issue with the amplifier. I suspect I'm in a minority of people who have issues. However, Monoprice's customer service was an excellent experience. They helped with troubleshooting possibilities, but at the end of the day none of them worked and they replaced it without any trouble.

I would recommend saving the box in case this happens to you, finding a box to ship it back in is quite a challenge. And it is quite a challenge to get this thing moved around and returned (its around 200lb).

But overall I'm very appreciative to Monoprice and their customer service for helping me solve this issue. Despite the difficulty I've had with the sub, I wouldn't hesitate buying from them again or recommending them to my friends.

Also, this sub rattled my walls so hard my Ecobee thermostat upstairs dislodged from its base. I think I am at my end game.

This outperforms the 16" THX sub above 20Hz and way better below 20Hz and has a smaller footprint. Unless you were going to put something above the sub, which I cannot imagine what, this IS THE ONE! I recently upgraded from a SVS PB-1000 Pro to this M-215 Dual 15in THX sub. I luv it! Never have I spent money better, lol! This sub was a HUGE improvement, I went from entry to endgame!

These guys are pushing the envelope on lowering the price with mass production and efficiency! All the stuff I bought is objectively great THX Ultra certified (which means rated for 3000 cubic ft space) and nothing else is anywhere near these low prices! I don't have a nice house with a dedicated room... only 5.1 in my old house... Now since I upgraded 5.1.4 ALL Monolith THX Ultra Certified.

I read a lot about their customer service... saw Youtube video about some fool saying he had to keep sending this beast back, which would be a pita! But that guy is a fool... He is cranking the subs with a 12.5Hz test tone, which is below our hearing and then complaining about some noise, which is dumb. Using the sub normally with real content, you wouldn't hear it, so who cares. ALL Ported subs will make port noise if cranked near their tuning freq with below audible test tone.

My point is I placed 3 separate orders:

1. M-215 sub
2. THX-365C (Center channel)
3. 4 THX-365 Mini-towers & 4 28" easel stands

One of the speakers was dinged and had to send back, everything else was perfect, shit happens. Their CS was fine... got booted of a chat and had to start over, that's annoying. They sent emails that gave instructions that were a little off, annoying, but it wasn't that bad. Open notepad on your PC and copy all info in there... EVERYTHING... so you don't need to type it over and over whenever doing chat with any company and you can copy and paste.

Anyway, I sent them a pic of the damage at the guy's request... Email wouldn't go through... he gave me a link, upload it here... Again, this is life in the Internet age, nothing works right, lol. He sent me an email with a return label.

These were easy to unbox carefully, and I keep ALL the boxes, so it was easy to put back in the box... dropped it off at FedEx store... day later they saw it was on the way and shipped me another one. ALL 4 times my order showed up in 3 days! Maybe I'm just close, but that's impressive right there. If you are not rich Monolith IS THE WAY! I am 100% happy and recommend!

The best loudest home audio I've ever heard. Love it. It's loud at 200 foot away.

Absolutely love this sub. Delivers studio quality bass for my remix studio.
It's certainly not small.
Comes well packaged and well made.
Great job Monoprice

So far I like the sub a lot. It noticeably increased the level of subsonic effects to my movies. I've got two other 12" subs that are good to about 16 Hz. It measures good to around 14 Hz. It is a very large and heavy object, so finding space in the theater was a bit of a challenge. I'd suggest using 4 people and a heavy wheeled dolly to move it. It should also be carefully calibrated so that it doesn't interfere with other subs or cause major issues with room modes.

Delivered to my front door with box in perfect condition on pallet. Easy to maneuver with hand truck once unpacked. Powered up and the bass is amazing. After a couple of weeks of use the sound became more natural. It does have an audible double-click plastic sound from inside the cabinet a few seconds after every power up, which I suspect is a relay to prevent a power-up thump - so I don't mind. I calibrated it with the Audyssey setup on my receiver with no problems. It blends perfectly with my speakers and makes everything sound so much better - clarity, musical depth, sound stage, and realism. It is the best addition to my system ever! Thanks!

This has to be the best subwoofer for the money I've ever seen.

Hits hard- clean - looks beautifully menacing - and is the envy of all my friends.

Funny- you could buy a single Klipsch 12" Subwoofer- or THIS ????????????????????????

Wow, this thing hits. Obviously it can get super loud with a 2000 watt RMS amp, but this sub is so immersive. No other listening experience is complete without my M-215. If you love bass, don't even think twice. When all is said and done, it'll be a top 2 investment you make for your setup.

This is a Juggernaut of bass. Honestly it may be too much for some. And possibly too much for me. But if you like a lot of unbridled, clean thumping bass that pressurizes the room, accept no substitutes.

This is a beast you don't want to have to send back.

I think this sub looked better in real life, versus the product pictures.

I did my initial testing and found I could not get enough output with my processor's gain maxed and the sub gain maxed. I had to turn my processor way up in order to get good output, so it turns out there was a problem with the input gain. I wanted to swap out the amp rather than return it, but that wasn't an option. It's really a shame because it's not good for the company or the customer. These are not easy to pack back up. I hope Monoprice changes its ways on dealing with component problems and allows customers (that are willing and able) to swap out components when there are problems. Sadly I returned the sub because I didn't want to possibly go through another return if something was wrong with a replacement.