Surround Sound Speaker Systems
- Written by Ross Jones
- Published on 23 March 2009
Theyâ€™re baaaaack! A long time ago (1973 to be precise) Walter Becker of Steely Dan asked Ken Kreisel to design a reference subwoofer suitable for mixing their Pretzel Logic album. For more than three decades, Miller & Kreisel was the name in speakers for music and motion picture studios. M & K also developed a tremendously loyal following in consumer audio, the MK 150 series speakers in particular creating fanatical devotion among owners.
- M-7 Front Speakers
- Drivers: One 1â€ Cloth Dome Tweeter, Two 4â€ Paper Mid/Bass
- MFR: 80 Hz - 20 kHz Â± 2 dB
- Crossover: Phase Focused
- Nominal Impedance: 4 Ohms
- Dimensions: 13â€ H x 4.9â€ W x 6.4â€ D
- Weight: 8 Pounds/Each
- Finish: Black Satin with Black Metal Mesh Grille
- Price: $399/Each
- M-4T Tripole Surround Speakers:
- Drivers: One 1â€ Cloth Dome Tweeter, One 4â€ Paper Mid/Bass, Two 3" Full-range Side Drivers
- MFR: 100 Hz - 20 kHz Â± 2 dB
- Crossover: Phase Focused
- Nominal Impedance: 4 Ohms
- Dimensions: 7.4â€ H x 6â€ W x 6.75â€ D
- Weight: 6.5 Pounds/Each
- Finish: Black Satin with Black Metal Mesh Grille,
- Price: $699/Pair USA
- M SB-12 Subwoofer
- Driver: 12â€
- Amplifier: 250 Watts RMS
- MFR: 20 Hz â€“ 200 Hz Â± 3 dB
- Low Pass Filter 40 Hz - 200 Hz, Continuously Variable, with Bypass
- Finish: Black Satin
- Dimensions: 15" H x 15" W x 17.25â€ D
- Weight: 45 Pounds
- Price: $1,099 USA
Alas, in 2007 Miller & Kreisel shut down its operations after 34 years. Later that year, one of its largest distributors purchased M & Kâ€™s intellectual property, but then things went quiet again. Fast forward to the October 2008 AES convention in San Francisco, where the M & K booth was a welcome addition, back in business. Chris Minto, U.S. sales manager for the revived company (now called MK Sound), emphasized that while there were new products in development (including an updated 150 series), for its re-launch the company was adopting an if-it-ainâ€™t-broke, donâ€™t-fix-it mode. So while I wasnâ€™t able to get my hands on the new 150 speakers (yet!), MK Sound was willing to provide a set of their M Series for review. The M Series are not technically new speakers, but they previously were only available to the pro market, where they are used in applications such as monitoring DVD mixes. So I was very interested in getting a set in my own home theater.
Design and Setup
The M Series are compact, sealed-design enclosures. There are two L/C/R versions. The M-7 2 1/2 way speaker reviewed here has a 1 inch soft-dome ferrofluid neodymium tweeter, with two four-inch coated pulp drivers handling the midrange/bass. The smaller M-5 speaker has the same tweeter as the larger M-7, but only one four-inch driver for mid-bass.
Refreshingly, there is no dedicated center-channel speaker. Center-channel speakers are a result of the market driving the product design, rather than best engineering principles. When consumers began putting center-channel speakers on top of their TVâ€™s, it looked nicer to lay the speaker down on its side, rather than have a Black Monolith rising from their displays. However, having three identical L/C/R speakers provides ideal timbre matching; simply put, all three speakers sound exactly the same. This becomes especially important considering that most dialogue comes from the center channel, and effect pans across the front of the soundstage move seamlessly from one side to the other without changing the tone or character of the sound.
The M-4T surround speaker is a tripole, sealed-design. The M-4T sports the same front-firing 1 inch tweeter and 4 inch mid/woofer as the M-7, inverted so that the mid/woofer is placed above the tweeter. On each side of the trapezoidal shaped M-4T is a three-inch driver wired as dipoles (out-of-phase). The combination is designed to provide even dispersion of sound across a wide listening area.
All M Series speakers use what MK Sound calls its Phase Focused Crossovers. The M-7 has a rated low frequency response of 80 Hz, the smaller M-5 and M-4T surround speakers are rated to 100 Hz (+/- 2dB). All the M Series speakers are nominally rated at 4 ohms, so youâ€™ll want to make sure your amp/receiver is comfortable driving a 4 ohm load. The MKâ€™s all have removable, metal-mesh grilles that are magnetically attached, and a single set of heavy-duty binding posts.
There are two M Series subwoofers, the M SB-8 and M SB-12. As the model numbers indicate, the M SB-8 uses an eight-inch driver, while the SB-12 reviewed here uses what MK calls its 12â€ MK SuperFast Deep Bass long-throw woofer (the phrase appears in white paint on the dust cap). Ordinarily, Iâ€™d raise an eyebrow by the time I got to the third adjective, but considering MK basically invented the modern subwoofer, I figured it was entitled to a little slack.
The SB-12, which is also a sealed (non-ported) design has a 250 watt RMS amplifier, with rated frequency response down to 20 Hz (+/- 3 dB). This bears repeating: a relatively compact subwoofer (basically a 15â€ cube) that goes down to 20 Hz without benefit of a tuned port.
The subwoofer has a manual low-pass filter adjustable from 40-200 Hz, which can also be bypassed, and adjustable phase control. There are two line-level inputs, as well as matching outputs for daisy-chaining additional subs, and speaker-level inputs. The M SB-12 came in a beautiful Black Satin finish. In fact, fit-and-finish of all the M Series speakers was outstanding, particularly at their modest price level, so that the white unpacking gloves that came with each speaker seemed quite appropriate. But I was anxious to take the gloves off (metaphorically speaking), and see what the new MK was all about.
Iâ€™ve heard my share of both consumer and pro MK speakers over the years, although I donâ€™t fall into the category of hard-core MK devotee (which probably wouldnâ€™t make for an objective reviewer). MK Sound started as a pro audio company, so the emphasis has always been on accurate reproduction without introducing any character to the sound (no built-in smiley/frown frequency response curves here). The M Series marketing brochure touts â€œuncannily realistic sound with fast transient response, razor-sharp imaging and accurate soundstaging.â€ That is a pretty good description of the classic MK sound, and not surprisingly also describes my experience with the M Series.
As long as weâ€™re tossing around adjectives, I would describe the M Series as revealing without being unforgiving. The combination of the sealed-design and Phased Focused Crossovers produced excellent transient response across the frequency spectrum, and imaging was indeed razor-sharp. Revolution, from the Beatles Love DVD-Audio, was a real treat on the MKâ€™s. Lennon and Harrisonâ€™s distorted guitars, McCartneyâ€™s driving bass and Ringoâ€™s pounding backbeat filled the room without sounding harsh or fatiguing.
Like most people, when I want to really give speakers a work-out I lean towards action films. Wanted stars Angelina Jolie and Morgan Freeman as a fraternity of assassins designed to rid society of bad people. This translates into lots of bullets whizzing (and bending?!) in slow-motion, car chases, explosions and all manner of good stuff. The MK Series shined with this material. The identical MK 7â€™s and tripole M4-Tâ€™s created a theater-like soundstage. My wife, who has become somewhat blasÃ© at watching these kinds of films, almost gave herself whiplash following the surround pans of gunfire swirling from the M4-Tâ€™s.
On the Bench
Remember my comment about the SB-12â€™s rated frequency response being flat to 20Hz from a small, sealed subwoofer? Take a look at this sine wave measurement of 20 Hz at 100 dB: 1.27% THD+N. Notice how the first harmonic (at 40Hz) is a full 35dB quieter than the fundamental.
Here is THD+N vs frequency. Distortion never goes above 4% even at 10Hz, and is under 2% for most of the low bass region.
Frequency response at 1 foot (red), 1 meter (blue) and two meters (yellow).
The M7, at the low end of its rated frequency response, produces 1.4% THD+N.
[insert 80 Hz THD + N]Fig 8
At 1hHz, distortion is 0.47%.
And at 10kHz, 0.376% THD+N. These are all excellent measurements.
THD+N versus frequency response:
White noise at two meters, basically in-room response (without any room EQ added).
As noted, the M7 is rated at 4 Ohms impedance. Electrical phase is within 70 degrees across the spectrum.
MK Sound is definitely back. The M Series speakers have all the classic attributes of the MK pedigree: superb transient response, pinpoint imaging and accurate deep-bass response, all in a compact package and affordable priced. Definitely recommended!