Two-way, affordable 15" PA speakers with horn-loaded compression-driver tweeters are a common sight at picnics and weddings across the world. Modern iterations of this ubiquitous speaker design are available from many manufacturers (including JBL, Yamaha, Mackie, Behringer, Peavey, etc.). They often come in molded-plastic enclosures that are lightweight, rugged, and incorporate the horn into the cabinet. This review is about the Monoprice 15" passive PA speaker ( $194 each an Amazon ), which fits the archetype for this sort of speaker design. The question is, can they be repurposed for 2-channel music listening or for use in a surround-sound home cinema system?

Back in February 2014, I posted an article about using a pair of Behringer B215XL speakers ($220 each) as L/R mains in a stereo system. That thread grew in popularity, and numerous AVS Forum members equipped entire home theater systems with B215XLs. As long as you use it with a subwoofer, it offers great performance. Within that thread's 3700+ comments, several members asked about the Monoprice 15" PA speaker, but nobody had any experience with them. Those comments stuck in my head and resurface every now and then, but until recently I did not act on them.

A few weeks ago, while suffering a bit of writer's block, I decided to look up the Monoprice PA speakers and re-read the specs. At that moment, they were on sale for $127 each, a price that—if the speakers proved to be reasonably competent—is ridiculously low. So, I ordered a pair, set them up, gave them a thorough listening, and the result is this review.

Features and specifications

This is a two-way PA (public address) speaker equipped with a horn-loaded compression-driver tweeter plus 15" woofer in a vented, molded-plastic enclosure. It's designed to be mounted on a pole or rest on its built-in rubber feet. This is not the sort of speaker you'd typically see in a living room, it is distinctly industrial and utilitarian in appearance. It would not appeal to anyone who wants fine wood finish speakers, but having said that, I do find it more attractive than the Behringer B215XL.
Since these are PA speakers, they feature an adapter for mounting on a tripod or pole.
Monoprice rates the power handling of its 15" passive PA speaker at 500 watts RMS, with 1000-watt peaks. Its 1.4" compression driver tweeter (1" exit) crosses over to the 15" woofer at 3.3 kHz (which is a bit high). The rated frequency response is 50 Hz to 20,000 Hz (-10dB) and sensitivity is listed as 97 dB/W/m. It's an 8-ohm speaker, weighs 37.3 pounds, and measures 27.5" (high) x 19.0" (wide) x 15.0" (deep).

Even though Monoprice does not sell a powered version of this speaker, removing the back panel revealed the crossover housed in a self-contained sub-enclosure; it's a handy feature for anyone who might modify 'em.
The crossover is easy to access and sits in its own protected sub-enclosure.
Setup

I treated a pair of Monoprice 15" passive PA speakers as I would any tower or bookshelf speakers I review. Because these are not tower speakers, I placed the pair on top of $5 black plastic bins (from IKEA) to bring the tweeters to ear height. I took a single 25-foot Monoprice 12-gauge Speakon speaker cable I bought on Amazon and cut in in half. Then, I connected the bare wires to the amp and plugged the Speakon connectors into the speakers.
Speakon connections are common in pro audio, I wish they were used for home audio too.
A Pioneer SC-85 AVR running in "Direct" mode acted as the audio processor for this system, with a BlueSound Node 2 as well as a DIY Windows 10 PC serving as sources. A MiniDSP DDRC-88A Dirac Live processor sat between my AVR and the system's amplifier, taking care of room correction EQ. A Classé Sigma AMP5 200 watts-per-channel class-D amp supplied the energized electrons that make the speaker drivers move.

Typically, high-sensitivity PA speakers require a subwoofer to shine since they are purposely not designed to play deep bass. At the time I received the Monoprice speakers, I was evaluating a pair of GoldenEar SuperSubs (that review is coming soon), so they served as the subs for this review. These speakers offer solid bass extension down to about 65 Hz (easily besting the B215XLs), so I set the crossover to 80 Hz on the SC-85.

Not only do PA speakers require a sub if they are drafted for residential duty, they also require room correction and EQ to sound right—it's absolutely mandatory. Inexpensive, compact pro PA speakers sacrifice linearity for sensitivity. The good news is that modern room correction (in this case Dirac Live) can handle the EQ adjustments such speakers need to sound best.

Performance

My first impression of these speakers was that they beat the Behringer B215XLs in terms of fidelity, aesthetics, and price. I fully understand the compromises involved with crossing-over a 15" woofer to a tweeter at 3.3 kHz. Namely, the woofer's dispersion becomes quite narrow at higher frequencies, and therefore does not match the tweeter's dispersion at the crossover point.

Measurements taken with REW (Room EQ Wizard) software and a UMIK-1 USB mic confirmed this predictable dispersion mismatch, and I agree that it's not desirable, but in practice it did not much matter. Once Dirac Live performed its mathematical magic, the speakers sounded great and measured well from anywhere within the listening area. Sure, you could hear the tonality shift if you went far enough off-axis. That shift starts to become noticeable at about 30 degrees off-axis, hinting at a horn with 60-degree horizontal dispersion.
A close-up view of the compression-driver horn tweeter.
Measurements from 1 meter, gated (4ms right gate): Orange = on-axis, turquoise = 15 degrees off-axis, purple = 30 degrees off-axis.
Distortion measurements (both from 1 meter and close-mic for each driver) described a speaker that manages to keep THD under control, even in the "breakup zone" of the woofer. I'm sure there are plenty of high-end speakers that do better in this department, but overall there was nothing to complain about. You can crank the volume up with these speakers and get the sort of clean, clear, dynamic sound that two-way bookshelf speakers with six-inch drivers can only dream of delivering.
Above 100 Hz, THD stays under 1%. Most of the time, it's under 0.5%.
Imaging and soundstage are aspects of audio reproduction that are tough to measure, yet fairly easy to experience and describe subjectively. Perhaps the biggest shock for me was how well the Monoprice 15s imaged. They were very precise, projecting a soundstage with depth and width that's at least on-par with what I hear from $500/pair bookshelf speakers and $1000/pair towers.

In order to test whether a modest amplifier could properly drive the speakers, I tried them with a Paradigm PW AMP ($500, review pending). It's a very compact, wireless, 50 watt per channel class-D amp that features Anthem ARC room correction and customizable bass management. It had no problem driving the speakers at very high output levels (100-plus dB, C-weighted average). The speakers also worked well with a Sonos Connect AMP ($500), which offers similar power output but lacks the sophisticated room correction of the Paradigm.

I was pleased to see these speakers are very easy-going on amplifiers. I used the Dayton Audio DATS 2.0 system to perform an impedance sweep and found it never dips below 7 ohms. This characteristic means most AVRs should be able to power them to very high output levels, especially if you use bass management and send the lowest tones to a subwoofer.
The Monoprice 15-inchers are quite amplifier-friendly when it comes to impedance.
Run full-range, without a sub or EQ, these speakers drop to -10dB at 55 Hz and again at 19,000 Hz in-room, which is close to the listed specs (which presumably use anechoic measurements). Post-EQ response was very linear from 80 Hz to 16,500 Hz—these speakers responded well to Dirac Live's automated room EQ and can also be tamed with other room correction systems or manual DSP-based parametric EQ.

While I can't confirm if these speakers will reach their peak rated output of 126 dB—I don't have a 500-watt amp and I do have neighbors—there's no question they can outplay typical 3-way towers costing a thousand bucks or more. When I turned up the volume, the lack of noticeable distortion or dynamic compression made them sound clean and appealing. The dynamic reserves serve the speakers well when it comes to reproducing percussion, as well as making the most of the explosive action-movie sound.

Listening

It's not often that a pair of speakers compels me to re-experience favorite tracks for hours on end. But, that's exactly what happened with these Monoprice PA speakers. It reminded me of my initial reaction to the Behringer B215XLs, but even better-sounding for less money. I performed all of my listening with the twin GoldenEar SuperSubs in the system and crossed-over at 80 Hz (the system's bass response extended down to 20 Hz).

Rock music truly benefitted from the grunt the Monoprices provide. Forget buying a pair of Cerwin Vegas if you want to blast whatever band makes your day. Turning up the volume for Jane's Addiction's 1988 album Nothing's Shocking yielded fantastic renditions of "Mountain Song" and "Ted, Just Admit It." The whole thing sounded close to live, and fresh.

I was surprised to hear the speakers reproduce "You Can't Always Get What You Want" by The Rolling Stones with crystal clarity. When the horns come in on the left during the song intro, there's a texture to it that would make you think you're listening to a super-pricey pair of audiophile speakers. Frankly, it sounded much more sublime that you'd expect by just looking at the speakers. There's a bit of cognitive dissonance to the experience, especially knowing what the speakers sell for.

It's always nice to experience jazz live and then hear the same material in album form. That opportunity arrived thanks to Blue Note recording artist Kandace Springs. I saw her perform tracks from her album Soul Eyes at South Kitchen and Jazz Parlor here in Philly. Then, I played the same tracks off her album at home through Tidal Hi-Fi. No offense to the live venue, but the JBL system they used did not do justice to Kandace's voice, or the piano she was playing. The Blue Note recording through the Monoprice speakers was the superior listening experience. Her cover of War's "The World is a Ghetto" sounded rich and soulful at home, whereas the live concert was diminished by the flaws of the PA system at the venue (or perhaps by the mix the sound engineer chose).

Dubstep demands speakers that can play complex electronic waveforms that produce unusual textures. To get the most out of the it, you need speakers that are not easily flummoxed. "Scum" from Datsik's 2013 album Let it Burn is a great example of the demands this style puts on speakers, and the modified square and triangle waves used in the bass-heavy composition had enough "tooth" and "grip" to provoke grins from connoisseurs of this admittedly polarising genre. Temporarily disabling the subs took away the ultra-deep bass rumbles but much of the song's "feel" remained thanks to the speakers' excellent mid-bass reproduction. But again, these are speakers that demand a sub or two.

The 2009 remaster of Enya's "Storms in Africa" is a darned-near perfect recording that can cause goose bumps when reproduced with sufficient fidelity. So there I sat, feeling almost foolish to be having an involuntary physiological reaction to the fidelity of what some might call "cheap plastic speakers."

Because I don't have a full surround-system's worth of Monoprice 15s, I can't speak to how such a system would sound. But, based on how this pair handled Kingsman: The Secret Service, Batman vs. Superman, 10 Cloverfield Lane, and 13 Hours (amazing sound in that film), I'd say they offer exactly what made people fall in love with the B215 XLs.

Conclusion

I'll keep it short and sweet. If you've been looking for a powerful, sensitive, pragmatic speaker that offers great performance for what it is, then you'll be incredibly hard-pressed to find a better deal. I don't know how Monoprice can deliver product at such an aggressively low price—at $160 each they are a steal, and when they are on-sale for $127 each, buying them could be considered larceny.

If you've got the room for 'em and can handle the form-follows-function aesthetics (or plan to put them behind a screen) then I can't figure out where you'd find speakers that offer as much bang for the buck. It's a classic Monoprice value proposition; with the 15" passive PA speaker, you get what you pay for. The only thing is, what you pay is about half of what similar performance costs coming from someone else.

These speakers are also easy to modify. For DIY-minded AV enthusiasts on a tight budget and who are allergic to woodworking, these could offer a great platform for various forms of tinkering—I plan to use a miniDSP 2x4 to convert them to active speakers and experiment with lower crossover points.

I'm not saying these are the right speakers for everyone or even right for most people. I am saying that if you can accommodate them, your home-cinema aspirations are grand, and your budget is tight, then a modest receiver should run five or seven of these without a problem. Add a competent sub and you'll have a full-range system going in no time. As long as size, appearance, and need for a subwoofer are not obstacles to adoption, these speakers are almost impossible to beat for the price.

REVIEW SYSTEM

Sources

DIY HTPC running Windows 10
BlueSound Node 2 wireless music hub

Amps and Processing

Pioneer Elite SC-85 AVR
MiniDSP DDRC-88A Dirac Live processor
Classé Sigma AMP5 5-channel amplifier
Sonos Connect AMP
Paradigm PW AMP