Boston Acoustics M-series System Review

If you’ve been on the sidelines of the home theater space, you might be surprised to find out that a lot has changed in just a couple short years. It used to be that a 5.1 speaker system represented the point of diminishing returns in home theater audio, but relatively recent developments have changed that. Not only has the ever-evolving technical world moved seamlessly into the Blu-Ray standard of 7.1 surround sound, but new digital processing technologies such as Audyssey DSX now allow systems to feed even more discrete channels from source material, creating 9.1, 9.2 (that’s two subwoofers), and even up to 11.2 surround sound. Who has room for all those speakers, you ask? We do.

Imagine, then, how excited we were to get a 10-box package from Boston Acoustics containing a plethora of its top surround speakers, dubbed the M-series. Next, imagine that we also happened to have the new Denon AVR-4520ci A/V receiver on tap, armed with the necessary horsepower to drive all that bling in a 9.2 surround sound configuration. Ok, you can open your eyes now and continue reading to find out how it all sounded.

Out of the box

After lugging a seemingly-endless collection of boxes to our test room, we began to unpack the speakers, revealing a handsome blend of utility and design. One by one we were greeted by sleek wooden cabinets glossed in gleaming piano-black finish. Each of the pieces struck a similar aesthetic, with heavy wooden frames accented at the top by curved strips of soft matte vinyl.

The cabinets were designed to be as stout as they are beautiful. Knocking at the cabinet’s side resulted in a dead ‘thunk,’ a tell-tale sign of excellent build quality.

We first erected the chic floor-standing M350, each of which harbored a tightly packed array of drivers beneath a thin veil of grill-cloth. Soon, an ever growing collection of companions began to surface at their feet, including two mid-size bookshelf speakers, a 4-pack of svelte surround speakers, a medium-sized center channel, and, finally, the robust MSubwoofer.

Features and design

Though a full M-series surround system isn’t likely to fit easily into smaller rooms, kudos go to Boston Acoustics for packing a lot of firepower into some pretty slender spaces. The three-way towers, or M-350B, stow an avenue of drivers running the length of their monolith frames, including four 5.25-inch polypropylene woofers, a 1-inch tweeter, and a lone 4.5-inch midrange driver.

Each M-350B is designed to handle up to 500 watts of power and has a rated frequency response of 45Hz-30 KHz. The speakers boast some interesting features, like a dimpled, EWB (Extended Wide Bandwidth) tweeter that Boston claims allows it to better reveal high frequencies. Other notable design points include aluminum bracings around the woofers, bass ports to the rear, and Boston’s “Lo-q” cabinet, which is heavily braced and insulated to enhance bass clarity and force.

The M-25B two-way bookshelf speakers follow a similar design aesthetic to their larger siblings, stretching back almost 11-inches deep from their slim front baffles. Each M25 packs a 5.25-inch midrange driver set below another dimpled EWB 1-inch tweeter, with a crossover point between the two at 3000Hz. The speakers can handle up to 200 watts of power, and have a reported frequency response of 62 Hz – 32 kHz. Like the towers, the M25’s cabinets are ported at the back and incorporate Boston’s “Lo-q” cabinet reinforcement.

The sleek center speaker, called simply the MCenter, deviates a bit from the driver design of the tower and bookshelf speakers. Foregoing the EWB tweeter of its colleagues, the MCenter uses a 2.5-inch “Balanced Mode Radiator” (BMR) driver, flanked by a pair of 4.25-inch midrange woofers. Interestingly, the BMR driver doesn’t just push sound back and forth like a standard driver cone, but also “bends,” supposedly allowing for more accurate dialogue reproduction. The crossover point for the tweeter is set at a remarkably low 700 Hz, giving it a huge amount of responsibility for the speaker’s sound reproduction.

As the smallest of the bunch, the MSurround take the opposite tactic of the M25 shelf speakers, measuring just 4.44-inches in depth. The slim dimensions and dual top-firing ports make the speakers ideal for flush mounting, and they include four-way mounting brackets to help in that regard. Like the MCenter, the MSurrounds utilize Boston’s 2.5-inch BMR driver instead of a conventional tweeter, which is set above a 3.5-inch woofer. The small size of the woofer limits the bottom range of the MSurrounds to a claimed 95 Hz, and the speakers top out at 22 kHz.

Rounding out our tour is the Msubwoofer, a girth-y, glossy black cube, powered by its own internal 500-watt RMS amplifier, with peak power output of up to 1000 floor-pounding watts. A 10-inch active speaker cone at the front panel is matched by two 8-inch passive radiators at the sides. At the back panel resides the plate-style amp, outfitted with a full set of controls including a polarity switch, crossover adjustment, volume, mute, and a bright blue LED that has enough spark to act as an effective nightlight for your home theater room.

Setup

We set up the speakers in a 9.1 surround configuration. Working from the front to back, our arrangement included the towers as mains paired with the MCenter. Roughly 4 feet from the mains we alternated placing a pair of Msurrounds and the M-25B as “front width” speakers. Likewise, we alternated between Msurrounds and the M-25B for the surround channels, with the Msurrounds fixed as our surround back speakers. After some A and B comparisons, we settled on the M25B as surround speakers of choice, leaving the Msurrounds holding down the “front width” fort. More on why we settled on this arrangement later. To drive the system, we used a Denon AVR-4520ci receiver with Audyssey DSX 9.1 processor, a Marantz SR6005 receiver, and an Oppo BDP-95 Blu-Ray player.

Stereo performance

As usual, we began our testing by checking out the M350B mains in stereo mode to see what they could do on their own. Perusing a wide selection of genres from our catalog, we were treated to an accurate reproduction of music, notable for smooth warmth in the midrange, a delicate and tactile brilliance in the upper register, and an impressively powerful low end that created enough pulse to send vibrations through our entire body.

Our first test subject was an SACD copy of Pink Floyd’s Dark Side of the Moon. The towers reproduced the dizzying effects of the album with a high level of accuracy and clarity, while maintaining thick warmth in the midrange that made for a very relaxed experience. Tracks like “Us and Them” were cast in a colorful wall of sound, accented with well cut guitar tones and refined stick work in the percussion. Cymbal sustains were especially gorgeous, as the speakers brought pristine shimmers of crash and ride cymbals that seemed to expand in the air in powdered clouds.

As we moved through other genres, we were surprised by the thick power of the bass, especially considering that the M350B’s have no on-board subwoofer. The four 5.25-inch drivers worked in tandem to create deep, seismic ripples from instruments like stand-up bass and kick drums. There were a few moments while auditioning acoustic music in which the low end was a bit too much, but we seemed to feel the presence more than we heard it, and it never crowded the upper register. Selections from our hip-hop catalog pulsed from the towers with brash, velvety grooves, while the upper register percussion and vocals were vibrant and clean.

The only complaint we mustered during this stereo scrutiny was that, at times, we felt the M-350 didn’t draw out the richer tonal colors of instruments like electric guitar and crushed snare. The trade-off, though, was a presentation that never so much as approached fatiguing.

Surround sound performance

After extensive surround sound testing, we have to say that the M-series speakers in our collection worked extremely well…as a 5.1 system. That is to say, the system sounds fantastic with the exception of the MSurround speakers. Much to our disappointment, the little guys did not contain any Mighty Mouse formula that would allow them to hold their own with their larger and more capable counterparts. As excited as we were for a completely immersive experience with the 9.1 configuration, the spherical illusion broke down quickly when it met the pale, underwhelming MSurrounds. As such, we wound up placing the bookshelf speakers in the critical surround role.

The Msurrounds’ weak performance was made more apparent because the balance of the system was extremely well voice-matched and performed brilliantly. The M350B towers brought a lush and exhilarating force to the front channels, while the BMR driver at the helm of the center speaker lived up to its promise, exposing clear and nuanced dialogue, as well as pristine detail in the subtler moments. The clarity of the center channel supported the M350 in delivering crucial dynamic contrast during the more explosive and action-filled scenes.

The M25Bs were also a potent addition to the team. Some musical testing of the speakers isolated in stereo revealed an effortlessly capable command of the midrange and treble registers, with excellent balance and detail. As such, the M25s served as extremely capable surround speakers, exuding a high level of textural depth when given their turn at the shifting sound stage. The storm scene from Fantastic Four, for instance, was so clear and present, we felt our heart rate increase a bit as the solar cloud burst through the space station, engulfing the team from all sides with its superhero alchemy. And the assault on Bruce Willis’ house by a commando team in RED brought a thick force of bullets from the front speakers, while the M25s drew us in with realistically traceable bullet strafes and ambient character movement.

Of course, the other key to solidifying palpable excitement from any surround system comes from the sinister depths below. Here the M-series was also well stocked. The Msubwoofer’s 10-inch driver and its 8-inch companions dug up the catacombs of the music and sonic effects with a rich blend of power and lyrical resonance. However, at $1200, we had hoped for just a bit more earth shattering punch from the deepest octave.

That brings up another point that detracts from our excitement over the Boston Acoustic M-series (apart from the paltry MSurrounds): the system is pricey. Actually, it’s very pricey. A bit of quick math revealed the full setup we tested costs upwards of $6500! Even swapping out the $1200 subwoofer for a cheaper bass box still leaves a whole lot of green to cough up for the other components. Had the MSurrounds delivered a convincing 9.1 effect, we would have had a slightly less severe case of sticker shock. But quite honestly, even excluding the MSurrounds, we’re just not sure the system’s performance is quite enough to contend with their astronomical bottom line.

Conclusion

The Boston Acoustics M-series brings an impressive display of balance, accuracy, musicality, and sheer power which we think is a huge step forward for the company. With the exception of the Msurround speakers, we were thoroughly impressed with the system, which created a gorgeous collage of sound, wrapped in a beautiful and well-engineered package.

That said, the speakers’ price seems a bit out of step with the rest of the market. While the system produces high-caliber performance, when compared to similarly priced systems like the SVS Ultra Series, we think it comes up a little short. If price isn’t guiding concern, we recommend checking out M-series (aside from the Msurrounds) – they are truly beautiful speakers. However, those on a tighter budget would do well to shop around before diving in.

Highs

• Balanced, powerful sound
• Excellent clarity and warmth in front speakers
• Professional build quality
• Sharp design

Lows

• MSurrounds are weak and poorly matched
• Slight lack of detail in instrumental timbres
• Expensive