M2 Sugg. Retail: $3500.00 CDN pr
Size 15 1/2″H x 9 1/4″W x 12 3/4″D
Subsonic 10 Sugg. Retail: $3000.00 CDN
Size 24 1/4″H x 26 3/4″W x 14 7/8″D
Manufacturer: PSB Loudspeakers Division
Lenbrook Industries, 633 Granite Court
Pickering, Ont. L1W 3K1
(905) 831-6555 FAX (905) 831-6936
(Reprinted from the Winter/Spring 2004 Audio Ideas Guide)
Every speaker maker is excited to introduce a new flagship model, and PSB’s Paul Barton is certainly no exception, since all he and his engineering staff know about speaker design has gone into this project. The M2 is the bookshelf model in the Platinum series, which now rests above the Stratus line in the PSB pantheon. The new S10 subwoofer is the biggest and most powerful low frequency reproducer that PSB makes.
Together, they seem a felicitous match, but I’ll expand on that below. A quick peek at the measurements amply confirms this. But first, a few design notes. The M2 uses a 1″ aluminum dome driver with ferrofluid damping and a neodymium magnet, with rated response to 33 kHz. The woofer/midrange employs a woven fiberglass cone with rubber surround and a 1 1/4″ voice coil driven by a 30 oz magnet. Crossover is at 2200 Hz in this reflex design with a slot port at the bottom of the front panel. The M2 can be bi-wired or -amped. Sensitivity is specified at 88 dB anechoic, and 90 db in-room.
Finish on both speakers and sub here was a metallic silver/grey, but black ash or cherry veneer are available; the cherry should look very handsome. The M2s weigh in at 55 lbs each, and matching metal stands are available.
Now to measurements. Talk about textbook! Using our new, simplied PNS (Pink Noise Sweep) based measuring system, the M2 on axis was +/-2 dB from about 55 Hz to 15 kHz; it was almost identical at 15 degrees off axis, and very close at 30 degrees. Even at 60 degrees off axis, the response was smooth and just a little rolled off in the top octave up to 10 kHz. At the bottom, the M2 was quite surprising for its size, down only 5 dB at 50 Hz, and -10 dB at 35 Hz; with a little more boundary reinforcement than our measuring position provides, this speaker can be made to made to provide excellent deep bass without mid-bass boom, the front port an aid here, since it doesn’t face into a boundary.
The curve at top is the SAR (Summed Axial Response), and what the measurements below add up to is very linear performance, again +/-2 dB across most of the audio range. This is a very accurate speaker.
And the trend continues in impedance, and impedance-related phase measurements. Impedance reaches a low of 5 ohms just below 100 Hz, and a high of 12 ohms just below 1 kHz, a variance of only 7 ohms. This ensures an easy-to-drive loudspeaker with virtually any amplifier, and with its quite high sensitivity, well designed tube amps may apply.
The phase curve below reflects the time coherence of the design, with a variation of +/-20 degrees or so, well below that of most two-way designs, ensuring excellent imaging, particularly in terms of depth.
And let’s talk about the S10 subwoofer. It employs a pair of 12″ woven fiberglass drivers with rubber surrounds and 2″ voice coils and 40 oz magnets all in a cast aluminum basket, mounted on front and back panels. The amplifier is Class H, producing 500 watts rms with 750 watts of dynamic capability.
The crossover is variable from 50 to 150 Hz, and both Crossover and Level controls are located conveniently on the front panel. Inputs are provided for both speaker and line level sources, and there are toggle switches for Auto on/off and 0/180 degree Phase as well as a master On/Off switch. Our review sample was in the same finish as the M2s with the other options available.
I did 2 sets of measurements, the standard ones to 20 Hz seen at top with the SAR curve, and dovetail nicely they do. At its highest crossover position, the S10 is +/-1dB from 100 to 20 Hz, and because the relative imprecision of the Crossover control (no marked frequency detentes), I made 4 measurements, representing various levels of the control. The continuously variable control can match the sub to anything from a small bookshelf speaker to a full range
floorstanding model. Probably about 3/4 rotation would work best with the M2 pair, and I confirmed this in listening setup and tests. The point here is that what looks great on paper, as here, does not take into account the cumulative overlap of sub and satellite as they cross over, sometimes causing a bump in that region. In sum, this one of the best measuring subwoofers in our experience, and I could hardly wait to listen to it.
I listened to quite a few different recordings, including our special assembled CD of our own and commercial recordings for speaker evaluation. In my own recording of Toronto composer Eric Robertson’s Psalm 67, at St. Paul’s Church in Toronto, the organ deep bass was palpable, extending to 20 Hz and below (Awake My Heart, AI-CD-010), and Doppler distortion (the modulation of higher frequencies by very low frequencies) was completely absent. The S10 is just about the cleanest and most powerfully tuneful sub I’ve heard.
Also in this track and others, the M2s showed exceptional depth of image, with detail to the back of the choir. On voices, massed and single, there was a very natural sibilance, with no hangover (rather like a really good condenser mike, which, of course, we use), and the transient characteristics on guitar and percussion were at least as precise. This is clearly (pun intended) the best tweeter PSB has ever employed, also heard in the crisp acoustic guitar sound heard in Sandy Denny’s Bushes and Briars from the album, Sandy (Island IMCD 132).
This definition was also heard in the rich, nuanced sound of Sergei Istomin’s baroque cello in the Bach Cello Suites (Analekta Fleurs de Lys FL23114-5; engineered by Clive Allen). We also listened to the Maazel/Vienna Mahler 4th (Sony MK 39072), and ended up listening to the whole thing, right to the end of Kathleen Battle’s beatific singing in the final movement. In other words, the PSB M2/S10 combination is a true high fidelity reproduction system that demands your attention, and keeps it; as colleague and friend Hy Sarick says, “If you can’t read and listen at the same time, and keep getting drawn into the music, then you are probably listening to great music on a great system.” Amen.