PSB Platinum M2 surround speaker system

I've had a soft spot for PSB speakers ever since I reviewed the first Stratus Gold for Stereophile back in 1991. Counting updates (the Gold i was introduced in 1997), the Gold has been PSB's flagship speaker for 12 years. That's quite a run in speakerland, where new models sprout like mushrooms.

The Gold i is still in production, and at $2699/pair remains a remarkable value. But PSB's flagship series is now the Platinum, introduced in late 2003. The new line is the product of several years of design effort involving the latest techniques, including Finite Element Analysis, laser vibrometry, and computer optimization. PSB founder and designer Paul Barton was also one of the first speaker manufacturers to use the measurement and listening facilities of Canada's National Research Council—some of the best in North America—and he continues to do so.

The Platinums cost considerably more than the Stratus models, but even topping out at $6999/pair (the Platinum T8, reviewed in Stereophile in November 2003), they're still a long way from the sticker-shock prices demanded by many competitors for their top models. I've always felt that all product categories have a point above which it takes a huge increase in price to produce a small improvement in performance—in other words, the point of diminishing returns. To my mind, that point for speakers falls somewhere south of $10,000 for a stereo pair. The Platinum series isn't cheap, but it's well below that level.

For this review system's left and right channels, we zeroed in on the smallest, least expensive speaker in the Platinum range: the stand-mounted M2. But because the center- channel is the most important speaker for soundtracks, we chose PSB's best for that position, the Platinum C4—even though it costs about the same as a pair of M2s with stands. Rounding out the group were the new S2 surrounds and SubSonic 10 subwoofer.

Boxes and Cones and Domes, Oh My!
With its finish of black ash or cherry veneer, molded port, dedicated stands, and die-cast aluminum side rails and top, the M2 monitor is relatively conventional-looking, yet attractive in a high-tech way. Two pairs of binding posts allow biwiring, if desired (I single-wired), and the speakers, like all the front-channel Platinum models, are magnetically shielded. The design's only downside is the stylish, aluminum-finished front baffle, which might reflect projected light if you position any of these speakers behind a perforated screen. The same could be said of the aluminum-dome tweeter, though this is a problem shared by many speakers.

The M2's woofer, like all the midrange/ woofer-drivers in the full-range Platinum models, has a woven fiberglass cone and a long-throw rubber surround. And since ultrasonic performance is apparently a must-have sales feature for flagship speakers in this era of high-resolution audio formats like DVD-Audio and SACD (though it's questionable if anyone but your pet dog and bat require anything beyond a clean 20kHz), the M2's aluminum-dome tweeter is said to extend to 40kHz, though it's specified to only 33kHz, –3dB.

The C4 center speaker is a complex, 3-way design using a distinctive, horizontally configured, D'Appolito-like array of five drivers. This is said to provide a wide horizontal sweet spot, for optimum performance with a group of listeners. In the past, such an even distribution of sound from a horizontal center-channel speaker has been typical only of designs with a vertically configured midrange-tweeter array.

The S2 surround employs identical woofer-tweeter sets on two cabinet faces, oriented 90° to each other. That's not so different from dozens of other dipole or bipole surround speakers, but the S2, apart from being one of the most solidly constructed surrounds I've seen (at 28 pounds each, I don't recommend mounting them directly over anyone's head in earthquake country!), is also one of the most flexible. The two pairs of rear terminals are not biwire connections, but direct connections to each woofer-tweeter set. Depending on how these terminals are jumpered, the S2 can be set up to operate as a bipole (both driver pairs operating in phase) or dipole (the driver pairs operating out of phase, producing a null at the front).

Another surround option is possible: power the two driver sets in each S2 separately in a 7.1-channel system. This eliminates the need to purchase (and find space for) an additional pair of surrounds—although PSB would, of course, be happy to sell three or four S2s with each system for a 6.1- or 7.1-channel setup! The excellent owner's manual includes detailed connection instructions for all of these options. For this review, I used one pair of S2s in bipole configuration.

The SubSonic 10 subwoofer is a little more stylish than most—a good thing, considering that it's a large, heavy, ported box enclosing two heavy-duty, long-throw 12-inch drivers powered by a 500W RMS BASH class-H amplifier. On the rear panel are inputs for both high (speaker) and low (line) level signals, a 0°/180° phase switch, and a switch to defeat the internal filters. Two controls on the front provide crossover frequency selection (50–150Hz) and output level. I used the SubSonic 10 in the usual home theater fashion: a line-level input with the lowpass filter chores handled by the preamp-processor. The sub's own lowpass filter was switched off.

The Platinum setup was typical of what I use in my 15.5 by 26 by 8-foot home theater space. The left and right speakers were toed-in toward the center seat and placed to the sides and just forward of an 80-inch-wide projection screen, itself about 4 feet out from the front (short) wall. The center-channel speaker was placed below the screen on a short stand, angled slightly upward toward the seating area, and the subwoofer was close to the right front corner, but far enough out from it to provide adequate wall clearance for the two drivers. The surrounds, operating in bipole mode, were positioned toward the rear of the room and angled slightly to increase sidewall reflections.

Listen and Learn
I generally live for several weeks—sometimes months—with speakers under review. More than half the review period is spent just listening to all types of program material—as you yourself would with any new piece of gear. After that come two or three weeks of more orchestrated listening, when the audition material is just as wide-ranging but a bit more organized, and the listening notes fly thick and fast.

By the time I got to Act 2 of the PSB tests, I'd already worked through variations on the Platinum theme (see sidebar, "Dial M for Marvelous"), spent time with the M2s and C4 in a smaller room while finishing my review of the Sonus Faber Cremona system (November 2003) in the big space, and put enough time on the final Platinum configuration to have an appreciation of how good the system was.

I spent a good deal of time, as I always do, listening to 2-channel music, driving just the left and right front speakers and subwoofer. "Now we're cooking," my review notes declared early on, as I auditioned a variety of male and female vocals to check out the M2's midrange—the heart of any speaker. The little M2s had an easygoing, relaxed, yet very detailed sound. And provided the program material itself cooperated, I heard no colorations—no boxiness, no nasality, no heaviness on male vocals, no edginess on female vocals. With the subwoofer properly dialed in, voices and instruments were naturally balanced through the midbass. The soundstage was tightly drawn, depth was natural, and centrally prominent pop vocals were so firmly anchored in the middle that the center channel might well have been operating—but it wasn't.

The M2's open, airy, silky-smooth top end also clicked on virtually all program material. It didn't exaggerate program flaws, but it didn't hide them, either. So when I say that the treble could sometimes sound a little crisp, with a slight metallic flavor, particularly at high levels, that isn't really a criticism. In fact, the speaker's highs were so clean that it encouraged high playback levels, particularly when mated to the SubSonic 10 to divert the deepest bass away from the M2's small mid/bass driver.

The bass from that SubSonic subwoofer was also impressive. It didn't reach down deep enough to reproduce the longest pipes on the most difficult organ recordings, the bottom half octave of synthesizer music, or the most woofer-crunching passages present on a few soundtracks—material that most subwoofers I've heard costing less than $3000 are also unhappy with. But it didn't complain about such material, either. It merely sat there quietly, or played at a low level—no nasty doubling, rattling, or port noises. But once the challenges climbed above 25Hz or so, the SubSonic 10 came into its own. Kick drum sounded punchy, double bass was clean, and bass drum was aggressively solid. Apart from those notes at the bottom of the lowest bass octave, organ and synthesizer shook the floor convincingly.

With all five channels (plus the sub) singing, the M2 system pulled off that most difficult of balancing acts: It reproduced the most cacophonous sound effects and the most subtly shaded music and dialog with equal ease. From the roar of the opening flyover of Senator Amidala's ship in Star Wars Episode II: Attack of the Clones to the concluding battle scenes, it provided all the excitement I could handle. The same was true with the explosive effects and wide dynamic range of Terminator 3: Rise of the Machines. There was no sign of dynamic compression, congestion, or distortion—the destruction and mayhem were appropriately raucous. But the music in both films was open and airy, with a natural sense of depth and an evenly distributed soundstage, all of which made a real contribution to the impact of T3, particularly its poignant conclusion. Dialog was also clean and natural, with none of that subtle muting of intelligibility I often hear at my off-axis listening position from center-channel speakers using horizontally configured drivers.

A few soundtracks I played through the M2 system did sound better-balanced if I dialed in a little cinema equalization. I also did much of my listening with the speaker grilles in place; removing them did not make a huge audible difference, but what little difference I heard favored the sound with the grilles on in my room.

If I had any reservation about the sound of the M2 system with soundtrack material, it was a slight overemphasis in the midbass, which may well have been largely due to the room, though I have not heard it to the same degree with all the subs I've tried in this space. Also, some other subwoofers I've used—though decidedly more expensive ones—shook the room more deeply into its joists with some bass passages, such as that Star Wars flyover.

I was able to make a worthwhile improvement by inserting the Subwoofer Optimization System (reviewed in our December 2003 issue) between the pre-pro and the SubSonic 10. This is roughly equivalent—in a review context—to moving the subwoofer to a different room. Apart from the ability to produce sufficient undistorted output at the lowest frequencies, the bass performance of any well-designed subwoofer—and the SubSonic 10 is that and then some—is more dependent on the room and the sub's placement within that room than on the sub itself.

While there are surround speaker packages that offer a more up-front, dynamically in-your-face presentation, and bass that rolls more thunderously into subterranean regions, there aren't many that provide greater overall satisfaction with music and movies of all descriptions than the Platinum M2. With a delicate, extended treble, clear, uncolored midrange, and solid, extended bass, it leaves little to be desired.

I can't finish any discussion of the sound of the M2 system without mentioning its performance with the soundtrack of The Lord of the Rings: The Two Towers (standard edition, Dolby Digital). Yes, it handled all the dynamic, over-the-top sequences convincingly. But the soundtrack engine that drives this movie—and the whole Ring trilogy—is Howard Shore's music. It takes you to another world, suspends your disbelief, and brings the whole fantasy to life. Whatever the scene calls for, whether it be a full-throated orchestral crescendo, the cry of a solo instrument, or an ethereal chorus, the score washes over you like a gentle rain or hits you like a tsunami. And through the M2 system, that music is magical.