When I stopped by the Monoprice suite at CES 2019, I could not help but notice the intriguing home theater speakers that the company had on display. The three new models include the 3-way Monolith THX Ultra certified  THX-365T Atmos mini-tower ($499.99/each)  and  THX-365C center channel ($399.99/each) , as well as the 2-way,  THX Select certified THX-265B Atmos bookshelf speaker ($349.99/each) .

Intrigued, I requested a pair to review on the spot and in response, Monoprice sent a 5-speaker system shortly thereafter. The rig is capable of rendering 5.1.4 Atmos (once a subwoofer is added). Once I had them set up in my living room, it quickly became apparent; these are high quality speakers designed for serious home theater applications.

Features and specifications

The stars of the show here are the two Monolith THX Ultra certified speaker models, the certified THX-365T Atmos mini-tower and THX-365C center channel. You get so much for your money with these models, including 24 dB (3 rd order) Linkwitz-Riley crossovers set at 550 Hz and 2.1 kHz, it's kind of insane. The 3-way design features a 2” silk-dome midrange with a neodymium magnet plus a 1” silk dome tweeter, also with a neo magnet. Both driver motors sport copper shorting rings.

The specs for the center and the mini-towers are identical, they have the exact same drivers, cabinet volume, etc. and consequently blend together seamlessly. The woofers are 6.5” units with pulp-fiber cones, butyl surrounds and have aluminum shorting rings in the motor.

Frequency response for these two models is 70 Hz to 20 kHz; you might say that’s a bit limited on the bass side, but these are sealed speakers and are absolutely meant to be used with subwoofers. Rated sensitivity is 89.5 dB at 2.83 V/1m for this four-ohm speaker design.

The THX-365T has an up-firing concentric 2-way Atmos driver built in, this driver uses a 5.25” mid/woofer and a 7/8” silk dome tweeter to render height effects by reflecting sound off your ceiling. Specifications for this part of the speaker are 120 Hz to 20 kHz response, 4 ohm impedance, 86 dB 2.83 V/1m sensitivity with a third-order Butterworth filter applied at 4 kHz. I would note that a lot more information than most manufacturers provide for the Atmos component of their speakers.

The cabinets are made from “five-layer HDF” and include horizontal shelf bracing. Twin five-way binding posts are located on the back of the cabinet, one for the main channel and one for the height channel. Magnetic cloth grills are provided if needed/wanted and the only available finish is matte black.

As for the THX-265B 2-way bookshelf, it relies on one 6.5” woofer plus the 1” tweeter, but also sports an Atmos driver. It’s good for shaving a few dollars off of the total system cost, and also for fitting into smaller spaces, but I would personally suggest going with an all mini-tower system, since (from my point of view) you get a lot more for that extra $150—a second woofer and the 2” dome midrange and a larger cabinet—which add up to THX Ultra, instead of the THX Select of these bookshelf models. Having said that, the quality of all these speakers is high and the bookshelf models were more than enough when serving as surrounds.

Setup and Use

Nothing too complicated here, I followed the set of instructions included in the Denon AVR-X6500H AVR ($2199 on Amazon) I used to drive this system. This is an important point (that I ran these with an AVR) given that the speakers are four-ohm models with modest sensitivity. But, the X6500H loved how they measure in-room (Audyssey measurements revealed good behavior even before correction) and once configured, I was able to push the whole system to very high output levels (at least in "living room" terms) without distortion.

Monoprice publishes performance graphs and you can plainly see that the 4 ohm specification is justified, so be sure your amp can deliver the required current. Certainly, these speakers can take enough power to justify external amplification that goes well beyond what an AVR can deliver; I don’t know what the absolute limit is, but it must be pretty high, and since these speakers don’t have to sweat deep bass reproduction, excursion limitations don’t really come into play.

Impedance chart of the THX-365T.
These speakers have measured performance that earned the THX certifications. Frequency response is remarkably linear through the entire range and bass roll-off is a smooth and gradual slope, perfect for easy integration with a powerful sub. For my review, I did not have a Monoprice monolith subwoofer on hand, but I did not skimp… I used a Rhythmik G25HP dual-opposed 15” to cover the deep stuff and the overall capability of the rig reminds me of the far pricier systems I tend to hear at CEDIA demos. But the best part is that this is a system that fit in my living room and where the capabilities of all the gear involved is well-balanced for the task at hand, with lots of reserve capacity.

Frequency response vs. SPL of the THX-356T speaker.
So here’s the crazy thing about these speakers… the THX-365T mini-towers are not just great for home theater, they are stunning 2-channel speakers. As with home theater, it is necessary to add a subwoofer to cover the bass region. But a simple 2.1 configuration featuring these 3-way marvels delivers the audiophile goods in astonishing quantities. You get profound three-dimensional imaging with speakers completely disappearing. Hyper detailed, smooth, neutral sound provide a subjective confirmation of the low distortion and linear frequency response you’d expect from a design such as this.

Most impressively, these speakers appear to offer a very consistent dispersion pattern that allow them to maintain imaging even when you’re not seated perfectly centered between a pair. This effect was pronounced enough that at times I would forget there is no sound coming out of the center channel. Physically removing the center channel altogether prevents the brain from assigning the sounds to it, but the floating three-dimensional imaging remained. I don’t know how else to put it, these are incredible speakers for the money, by any measure.

I truly don’t see any reason to go through some long list of tracks to describe how this or that track sounded through the speakers; they bring out whatever the artist “intended,” regardless of whether the artist is the musician or the engineer who mastered the music. My recent playlist has included the very latest Bassnectar (Reflective Part 4), some Beastie Boys (Hello Nasty), just a few days ago, the latest chemical Brothers release No Geography, as well as Riff Raff’s Pink Python. The capacity of these speakers to plant the vocals right in front of you, even if you are not centered, is not just great for listening to tunes with your significant other, it has ramifications for how these speakers cover a multi-seat AV installation, including home theater applications. Namely, by sounding the same regardless of where you sit (within reason) you get a seamless soundfield that is more like a holographic 3D bubble that puts you in the movie, rather than the more gimmicky effect of sounds bouncing from speaker to speaker that less refined rigs deliver.

Of course, the design of the speakers is explicitly home theater centric, especially with the inclusion of Atmos capability. To that end, I watched each major new UHD release that featured Atmos or DTS:X sound through this speaker system. I rent, I have a rectangular living room with a hard and flat ceiling, and I enjoy a 3D immersive sound, so this sort of speaker system is perfect for my living arrangements.

In terms of content, I enjoyed the entirety of Bohemian Rhapsody, Bumblebee, Spider-Man: Into the Spider-Verse, Aquaman, Ralph Breaks the Internet and First Man with this system. And all I can say is that I have no need or desire for anything more out of a 5.1.4 system than what I hear from this rig. I mean sure, I know you can get even more hardcore, but I’d quite literally have to move out of the city to go there.

On the whole, that was part of the speaker system worked as well as other reflected-sound solutions I’ve heard. Ideally, you’d have physical speakers up there but between the wiring and hanging them, reflected sound is a nice and easy way to make it work. But the core of what makes this system so good is how well the center, towers and bookshelf models work together handling LCR and surround duties. The THX-365C center channel and the THX-365T mini-towers blend perfectly, the front stage is seamless. Furthermore, the bookshelf THX-265B is itself a rather competent speaker that blends well with the front stage; I came nowhere close to using their full capacity with any content I played, so it may well be that they are “enough” for most applications.


Perhaps you noticed, this is not a technical review. I’m not too worried about it, here are the measurements provided by Monoprice. I’m certain that soon enough other reviewers (who have the space to do anechoic measurements, perhaps outdoors) will get around to measuring these speakers. I am privy to the graphs that come out of Audyssey (and also Dirac Live, fwiw) and can plainly see that these speakers behave well.

Transparent playback that reveals the essence of music or sound, reproducing it as it was when created, is the core function of a good speaker system—these Monoprice Monolith mini-towers do it better than most. Anyhow, soon enough you won’t have to take my word for it. These speakers are shipping now, and I expect them to be in the hands of new owners soon enough. I look forward to reading the feedback from other music and movie lovers who discover what these Monoprice monolith speakers can offer.

I expect these to be nothing less than a complete game changer at this price point, especially for living rooms, and other spaces where in-ceiling Atmos is a non-starter... but very high performance at a reasonable price is desired. This is a Top Choice, easily.

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