Product Review - M&K MX-5000THX Subwoofer - February, 1996

By David Moretti

M&K MX-5000THX Subwoofer; Active push-pull subwoofer; two 12" drivers, 400 watt rms built-in amplifier, two RCA jack line level inputs, input level control, low pass crossover frequency (36 dB/octave) control adjustable 50 Hz - 125 Hz, phase switch, THX - non THX switch, switch for use with one or two subwoofers; size 23"H x 15 1/2"W x 23 1/2"D; weight 115 pounds; $2,495; Miller & Kreisel Sound Corporation, 10391 Jefferson Boulevard, Culver City, California 90232; Phone (310)-204-2854, Fax (310)-202-8782.

If you have read my bio in the About section of the magazine, you know that I play music for a living, as well as listen to it for fun. And, I play bass. Electric bass, in fact. I was delighted when Dr. Johnson asked me to write for Secrets because, as a musician, I am very particular about what I listen to at home, coming out of speakers. I am spoiled from hearing music live most of the time. Of course, the bass that I play at work also comes out of speakers, so it is appropriate that my first review should be for a subwoofer. The subwoofers that I have at home are built a lot differently than the ones I use at work, but the idea is the same: put out low notes deep and clean. I have not listened to M&K before (except for an occasional walk through at the hifi store), so I really looked forward to having one to put through its paces on my own.

I have a home theater in my den, and I decided to test the M&K MX-5000THX in my system, with all the furniture and clutter that I, and probably most guys, have in such an environment. I'm not talking about beer cans and potato chip bags, but . . . you know . . . stuff that is laying around in a comfortable family room. Dr. J asked me to at least put everything in its place for the test, but I said, "no, no, no, . . . it's got to be a test in a room that I would be listening to the sub if I had owned it and was just watching movies like any family." He said OK, but that I should explain that in my review. Consider it explained.

The 5000 uses two massive 12" drivers arranged in a push-pull configuration. Please view the animation example which demonstrates push-pull driver motion. (Note: Your browser must support animated gifs to view this animation.)

That means when one driver cone is moving out of the enclosure, the other is also, but, due to the way they are mounted, one is moving out of its basket while the other is moving into it. The result of this arrangement is a reduction in even-order harmonic distortion. Also, the enclosure can be smaller and still provide optimum space for the drivers to deliver deep bass. You wouldn't know that from the 5000. It's huge! The biggest sub I have ever seen, for the size of the drivers. Even the grille frame is heavy.

Anyway, I set this baby up with the subwoofer output from my surround sound preamp (preamp sub-out set to full range), and I put on some movies that I know have power bass. The first thing I have to say is that the 5000 clipped when I turned up the volume. I wasn't expecting this, since it has a 400 watt amp. So, I was a little disappointed. I turned the volume down to a nice comfortable mid-level and just watched movies for a week or so (about 5 movies), and played some CDs. The 5000 performed very well during this time, the lows coming through clean. Then, after about 20 hours of use, I turned it up full volume again, and surprise, no clipping! This sub obviously has an extreme tightness about it when it is new. My analysis of this is that the drivers are built so that they are very stiff to begin with, M&K knowing that the owner is going to crank the sub. Once the drivers are used for a while, they loosen up to just the right level. In other words, if they were loose to begin with, using them would make them settle into a condition of being too loose. So, don't make the foolish mistake that I did and turn on the 5000 for the first time, thinking that what you hear is what you got for your 2,500 dollars. This sub changes more over the run in period than any speaker I ever bought (well, I haven't bought it yet, but I might, if the boss doesn't beat me to it). Once it settles in, then crank it up and watch all the termites in your attic take a hike. This sucker is clean, deep, and POWERFUL! If you like the idea of having a double barreled 12" anti-aircraft cannon in your home theater, this is your opportunity. If you have a THX preamp, there is a THX switch on the back of the 5000 that disconnects the crossover and volume control so the preamp can completely control the sub. There is also a phase switch, and a "two subwoofer" switch just in case you happen to be rolling in cash and buy two 5000s. (Note: After David returned the 5000 to the lab, we tested it with the Audio Control Phase Coupled Activator, and the sub performed beautifully. See last week's review for details. Ed.)

John came over and put the calibrated microphone for his SPL meter 3 feet in front of the 5000. He measured 100 dB output at 20 Hz before we could hear the drivers start to rattle a bit (104 dB at the listening position by my couch). Of course, the clutter in my den started to rattle too, and Dr. J was laughing while I went around putting heavy books all over everything to stop the buzzing and the creaking. Just to put this in perspective, he measured about the same output from my own 15" servo feedback sub. I can get more output with the servo sub upstairs, but we brought it into the den and put it near the 5000 to get a fair comparison.

Warble tone frequency response of the 5000 (reference frequency 100 Hz set at 90 dB):

Frankly, my servo sub is somewhat more musical, but the 5000 has more SLAM. This is to be expected, since it is designed for home theater. It's OK for CD music too, but it is really for "Terminator", "True Lies", and all those other films we like so much. If the MX-5000 can respond to 1/3 Hz, perhaps M&K could license it to hospitals for use as an iron lung. I was going to hook it up to my Fender bass, but J said, "Oh no you don't. And if you scratch that beautiful oak veneer finish, you have to buy it!" Hmm, maybe that is the only way I can get this sub for my very own.

David Moretti

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