Specifications:

A Long, Long Time Ago, Even Before Las Vegas . . .

When it comes to the cult of “high-end” audio, I'm very much a recovering addict.  I've had my share of snake oil, magic quasi-scientific “upgrades,” extensive “burn-in” practices, exotic cable materials and construction, etc.  No more.  I've been on the road to being more fiscally responsible, and in my opinion, having incrementally more accurate sound reproduction for a good handful of years, without substantially increasing the total hardware cost of whatever set of components makes up the audio portion of the entity known as my system at any given moment.

That's not to say that luxury goods don't have their place.  I believe that charging more for a heavier chassis, thicker faceplate, extensive cosmetic features, and on rare occasion the bleeding edge of R&D, is truthfully just a matter of supplying for a demand.  If people primarily want “the best” stuff, and have a good sum of money to spend, the easiest way for those people to achieve their objective is to buy that which is obviously, and often outwardly (visibly) “superior.”

Though I must admit that “cost no object” or similar attitudes to audio reproduction warm my heart, it's not an approach I can personally support with my own wallet.

Due to my stubbornness regarding high quality sound reproduction, instead of giving up the continual progression I began when I took my first step beyond that Fisher boom box, I have instead changed my approach to audio, placing emphasis on verifiable fact over fantasy and developing an intolerance/immunity to most money-sucking parasitic cogs of the “high-end” marketing machine.  It's not that I've stopped listening to the equipment for myself or resorted to comparing manufacturer published spec's, but that I've learned to filter out hype with increasing success, and I'm a much happier camper so far.

Having Explained Myself, Let Me Get on With It.

Captain Purple is, without a doubt, the weirdest super hero I've ever met.  Grape costume aside, his exuberance for the seemingly mundane puts many Dungeons & Dragons buffs to shame, consistently riding an edge between irritated and overjoyed, radiating comedy, commentary, and sarcasm at a clip to put a Geiger counter into heat.  Not that Captain Purple looks weird for a super hero.  He's just one of those guys that you might think is listening to the voices of marshmallow lords, or leads a cult, depending on the day.  But that's just the brilliance of his disguise.

Few would guess that, once engaged, Captain Purple could unleash such a fury of audio knowledge on any given single topic for hours.  If you happen to catch the great Purple, try bringing up the history of pins 2 and 3 on the XLR connector and the “damn f@#&ing roadies.”

The less entertained might wonder about the relevance of Captain Purple, beyond his inevitable place in super hero history.  As formidably as Captain Purple cuts his cake solo, operating occasionally under the alias Barry Ober, when his powers work in tandem with the rest of his under cover super buds, watch out.  “Plucky Chucky,” (Chuck Back) can enter into a melee of three conversations simultaneously, confusing his would be adversaries with eyes darting like a speed fiend and verbiage so profuse yet relevant that his victims fall into a rapt stupor until they feel compelled to return with cookies.  The ever elusive Ken Kreisel, the head master of the Miller & Kreisel (M&K) design juggernaut, I've only seen once, smiling knowingly yet skeptically as a somebody lobbied that DTS was the final word, and format, for multi-channel music.  (Of course, the next year, DVD-Audio and SACD made an appearance with high resolution multi-channel sound.)  The duo of QC experts- Misha Pak and Mr. Mendez, reportedly listen to everything that leaves the compound, err . . . I mean factory.

When you combine such individuals with the minions who make up the rest of Miller and Kreisel Sound Corporation, you have one of the most formidable forces on earth, undaunted by the fashionable use of oversized surrounds, unphased by gimmicky “exotic” driver materials, and unmoved by the temptations of inflated power ratings.  If one company has steadfastly disregarded the trendy fads of the audio cliques to stay true to their course, holding their products to the same unwavering philosophy and standards that brought all of it together from the beginning, it would be M&K.

Following a philosophical discussion with Chuck Back a couple of years ago regarding the pressures of perceived technology vs. real value, Chuck replied, “We find that if customers can do a direct comparison between our products and others, we get our share of sales.”  Their share includes quite a chunk of the most prestigious clients in the industry.

I can't really claim to be M&K's top client, by any standard, but I can testify that after a long personal bout of trying many different loudspeakers on for size, one of the few companies that earned my ongoing attention and patronage through an unyielding commitment to a simple, honest, unchanging philosophy of sound reproduction is Miller and Kreisel.  They make their products the best they know, putting considerable time into firmly grounded R&D, without the flim-flam flash in the pan trends that rule so much of the fickle audio “designer” community.  Nor do they place much, if any, consideration into cosmetics beyond clean, functional, and occasionally slightly stylish.  Instead of going for sparklers, M&K has continued to refine and polish their guns, offering exactly what I'm looking for in loudspeakers.  Honest performance, no frills.

I'm beyond trying to remain the unbiased, scholarly journalist poking at the world from an ivory tower.  Instead, I've messed myself and relegate the ivory to washing armpits.  In addition to M&K, there are a whole handful of loudspeaker companies I truly respect and admire as sincere and competent purveyors of real, genuinely good, high-value equipment.  Amid the sea of misunderstanding, misrepresentation, and marketing fluff, I don't think such companies get enough attention.

So how's this going to be different from any other typically glowing M&K review?

FULLY ACTIVE MY FRIENDS!

Is that how Bob Barker feels?

Brian Florian and I have been trying to get a whole series of active loudspeakers for review to illustrate the inherent benefits of fully active design.  Unfortunately, in the consumer market, pickings for fully active loudspeakers are slim and skinny.  It's not really that the engineers behind the best manufacturers don't know the advantages of active loudspeakers, but rather that loudspeaker manufacturers who've been around realize the difficulty of selling a product that the bulk of the consumer market isn't ready for either because of lack of understanding, sheer stubbornness, or plain box culture (balancing the desire of wanting expensive boxes with the desire of wanting more of them.)  Of the brands and models we had targeted at last year's CES, only M&K followed through on supplying samples for the shootout, so the shootout became a product review.

The S-150P “main” speakers, SS-250P Tripole surround speaker, and MX-5000 mkII subwoofer are not only fully active loudspeakers, in that each driver set (tweeter, mid-bass, subwoofer) have dedicated amplifiers, with their frequency divider networks before amplification, but are also M&K's ultimate expression of doing a high quality monitoring system “their way,” unfettered by design restrictions.

Somebody's out there steaming, “Why would I limit myself to their amplifiers, when I've got this great XXX watt, mucho heavy monster amp on/in my floor/rack that can drive any conceivable load, with a power supply massive enough to crank a winch?"  Believe me, I understand.  I have a fully paid subscription to that mindset, a few actually.

Let me first say that M&K has displayed their prowess with electronics, even if their reputation lies with loudspeakers.  The BMC Mini Bass Management Controller is one of the cleanest, most transparent pieces of gear I've had the pleasure not to hear, and the LFE-4 provided for this review (fully balanced input and output Bass Management Controller developed for professional mixing consoles but compatible with unbalanced consumer gear by means of selectively soldering connections) meets that same standard in spades, clubs, diamonds, and even purple horse shoes.

Regardless of all this, let me make a more relevant statement as to why we should consider an active lifestyle as a viable course for an audiophile.  Unfortunately, it requires a generalization, which in turn will demand many more qualifications.  The whole rant gets long, so we'll squeeze it into a link.  Let me squint a bit, and here it goes, squeeze . . .

The Benefits of an Active Speaker Lifestyle

From my past experiences with M&K passive loudspeaker and powered subwoofers, and very terse listening sessions of the S-150Ps at CES shows of yore, I had some pretty high expectations, but felt skeptical about amplifiers supplied with speakers.  Whether or not it's true, it often seems that loudspeaker companies can't do amps worth a Richard, and that the same applies to electronics companies that get an itch to try out the loudspeaker market.  My “reference” front speakers are more or less M&K S-150 “satellites,” powered by some pretty well to do amps.  I had no doubt that its powered cousins would be in the same ballpark when it came to it, as they're almost identical in driver complement and basic design goals.  But, as to whether they could design and build power amplifiers with the same muscle as those used in their subwoofers and still maintain the same degree of transparency, poise, and finesse of my beloved Aragon brutes, I wasn't exactly putting up the 8008s up for auction.

While active speaker systems are technically far more elegant, if the electronics don't cut it, vocals can develop an irritating edge, detail falls into a veil of amorphous fuzz, and the soundstage depth flattens into a two-dimension cardboard poster.  In short, it can easily become more of a sound reinforcement solution than a quest for fidelity.  And, if the powered versions weren't actually better than my own passive units driven by the big, overbuilt tanks, it could turn into an all out indictment of M&K's dedication to developing the active loudspeaker market.  If the internal amplifiers of the S-150Ps were just “good enough,” I didn't think they would be.

General Notes on Subwoofer/Satellites

To repeat myself from other occasions, subwoofer/satellite configurations, though ultimately more flexible than stand alone ‘full range' counterparts, depend far more on careful user setup than their towering cousins.  Many instances of disappointment I've had with sub/sat combos have been due to substandard setup.  If anybody ever spouts off with, "The subwoofer can go pretty much anywhere," or "the best place for the sub is always in the corner," they've just written you a gift certificate for ignoring the rest of the conversation.  

“Satellites” avoid low bass duty with an intentional and controlled decline in bass response, usually at 80-100 Hz, and so a good combination of calibration and placement is even more crucial than your more typical semi-full range or even “bookshelf” type loudspeaker.  The upside is that because they're designed specifically to integrate with a subwoofer, potentially at a known frequency, with known slopes and phase relationships of an active crossover (a.k.a., standard THX spec,) if the integration is done with care, the transition may prove more sonically transparent.

With a crossover as high as 80 Hz - 125 Hz, not only does the subwoofer placement become more critical, but it does not do to use the subwoofer level setting or crossover point adjustment as a tone control for subjective effect, anymore than one should try to adjust treble levels by simply throwing a rheostat in line with a tweeter.  If one decides to take the route of miscalibration for the sake of personal taste, and likes the results, fine.  If you have a lousy experience with any loudspeaker and don't know for a fact that the system was calibrated properly, consider putting any opinion on the shelf until the calibration's been done, and done well.

In addition, releasing the satellite design from deep bass extension opens up potential advantages in allocating manufacturing and design resources to focus on a narrower (literally, in terms of bandwidth) task.  Deep bass reproduction costs in larger or more drivers, larger cabinets, more power, etc.  Keep in mind that I speak generally, but many designs may often sacrifice performance in the upper-most range of the mid-bass driver in order to allow better bass (such as using a larger driver less suitable for higher frequencies) and/or just do a poor job trying to extend their low frequency limits, sacrificing articulation in the process, ending up somewhat fat and chubby, perhaps with more distortion and less dynamic capacity, with or without a subwoofer.

The potential downside of satellite speakers is that they require a higher crossover frequency by necessity.  A tower-style loudspeaker may still be better off with a crossover frequency roughly 80 Hz or higher, but a true “satellite” demands it.

I would repeat that even if you have truly full-range speakers, a substantially higher crossover frequency than the limits of your full-range loudspeakers might still be beneficial.  Check out our rant on that very subject:

Miscellaneous Ramblings on Subwoofer Crossover Frequencies

Getting to the Contestants . . .

To address how the subjects of this review relate to the aforementioned technical issues…

• All of these speakers, from the ground up, are fully active in that the mid-bass drivers have a dedicated amplifier, the tweeters have a dedicated amplifier, the “full-range” drivers for the SS-250P's dipolar elements have a dedicated amplifier, and the subwoofer has it's own as well, all with frequency dividing networks placed before the power amplifier section.  They are likewise designed as a complete and coherent system, and can therefore benefit from all of the advantages of an active design in the areas of dynamic range and output consistency across the board.  There is a feature worth mentioning, which is that the S-150P model uses a single air-core choke on the top and bottom tweeters, for the sake of keeping the vertical dispersion relatively smooth.  I could be a pain and insist that they'd be MORE active if there were two amplifiers for the tweeters, one for the middle and another for the top and bottom, so as to implement the selective taper without any passive components at all, but it seems that the benefits would be mild, if existent at all, and the cost would be substantially higher.  While I consider myself an idealist, this doesn't really bother me, and the units are expensive enough to satisfy the snob in me as is.
  
  

• The S-150P and SS-250P are “satellites” in the truest sense, in that they need a subwoofer and a “high” 80 Hz crossover point, like every THX loudspeaker system, as the speaker response itself forms half of the high-pass section of the sub/sat splice.  Because of this, their total performance depends very much on careful and conscientious setup.  That means, at least setting all speakers in your receiver's or SSP's bass management setup to “Small,” setting the crossover frequency to 80 Hz, with no exception, and conforming all channel levels, including the subwoofer level, to equal output with proper calibration techniques.  It sounds like a real headache, but the whole process should be done with any loudspeaker system anyway, perhaps with a little variation, regardless of the loudspeaker system of choice.  Given those requirements, it has been my experience that M&K products, particularly their subwoofers, have been unusually convincing with "higher” crossover points, even compared to some very good competition.
  
  

• For the record, the amplifiers are supposedly based on a fully differential (i.e., fully balanced, just like JJ loves) design with bipolar transistors on the outputs.  I think that the end performance result is more important than the methodology used, but as a matter of interest, some have remarked that bipolar transistors sound “crispy,” while FET-based output devices, like MOSFETs or HEXFETS sound fuzzy and smooth.  I've heard both sound fantastic, but if you've got a categorical aversion to or preference for either, now you know.
   

• M&K uses exclusively sealed alignments, as opposed to bass-reflex.  I won't commit to their position that sealed systems are inherently better, but in my opinion, it makes getting good results much easier, as too many of the ported designs I've listened to sounded as such, with an identifiable character.  In the case of the “satellite” speakers, a sealed alignment makes them not only easier to blend with the subwoofer, as the behavior is more predictable, but THX mandates a sealed alignment, as it's the only way to achieve a deliberate and consistent 12 dB/octave acoustic high-pass roll-off.  Another feature of sealed subwoofers is that they usually have a more gradual roll-off at their lower frequency limit, and therefore tend to have more usable extension than their bass-reflex counterparts given a specific – 3 dB extension spec.

For anyone interested in the details,  of sealed vs. bass reflex,  we just happen to have an article for you . . .

How a Hole-in-the-Box Works - A Big Dig into Bass Reflex

General Notes of Interest (We Hope)

Regarding . . . All of Them

• All of the units offer unbalanced RCA or balanced XLR inputs.  The XLR input is an option on the MX-5000mkII, so if it comes down to ordering one for yourself, make it known what you want.  The MX-5000mkII I received only had a single XLR input, vs. two RCA inputs.

• The entire set, as typical for M&K, had amplifier sections very much built beyond what their brochure numbers would suggest if you compared numbers with many other companies boasting triple digits, with heavy heat sinks and over-sized slow-blow safety fuse values that imply extremely under-rated amplifiers.  For instance a 5A fuse on the S-150P, a 7A fuse on the SS-250P, and an 7A fuse on the MX-5000 mkII, all of which post power ratings modest by today's optimistic standards.  Ignoring the details of phase shifts, this correlates to the potential to safely draw roughly, 550, 770, and 770 watts each from their respective sockets within a “normal” operating margin, implying that the ratings are indeed conservative, allowing for quite a bit of “headroom.”

• The cabinets aren't flashy, but solid.  Their black bead finish is easy to clean, and fairly durable, as tested by the munchkins.  I would also mention that this saves the buyer money.  Putting a furniture quality real-wood finish on your loudspeakers ups the consumer's price hundreds of dollars each at a minimum¸ and improves sonic performance zilch.  I'm thinking of a pair of mini-monitors where the options of a glossier finish and machined aluminum side panels up the retail price a couple thousand dollars a pair.  Think of that next time you run across an absolutely gorgeous, shiny, wonderfully crafted cabinet, and how much of the asking price went into the lipstick.  Still, I bought my S-150s in dark cherry a couple years ago, and haven't regretted it yet.  I enjoy looking at the wood.  There's nothing wrong with paying for furniture, so long as you realize the value that's gained by the extra cost is that of furniture.  Offering products exclusively with the great wood veneers, shiny doo-waps, and the associated higher price tags can increase perceived value.  That's probably why M&K has stuck with their black for so long, occasionally offering a simple wood finish as an extra option time to time.
  

• A fixed or variable gain switch.  The fixed setting conforms to THX input sensitivity requirements, and is useful for most consumer receivers or preamplifiers.  The variable gain switch allows input sensitivity to be adjusted via a knob on the back.  

Regarding . . . the Subwoofer 

• The most obvious statement I could make is that the MX-5000 mkII is physically a massive brute.  I didn't weigh it in, but it's not pleasant to lift with one person.  It has two low frequency contours.  They're not the “Flat” vs. stupid humped “Video” contour that I've seen on some other products.  Both are flat settings, but with different amounts of taper in the low frequency extension curve.  The THX setting conforms to THX Ultra spec before THX Ultra 2 changed the spec.  As the original THX spec allowed, the “THX” setting provides a slow taper in response so as to maintain a projected flat room response to 20 Hz and a little below while maintaining slightly higher output capabilities.  THX Ultra 2 requirements for subwoofer certification, dictate that a subwoofer dip down to 20 Hz without the assistance of room boundaries (which the “anechoic” setting claims to do) so that the bass response would be flat in a parking lot, and then offers a room boundary compensation circuit in Ultra 2 processors that lets an Ultra 2 certified sub perform just as an original Ultra without the processing.  Whatever George.
   

• I've yet to occupy a room without room boundaries, and if we're gonna EQ, I'd rather do it for the specific room, but that's probably a reason he's rich and famous.  You can put the switch wherever you like.  I tried both, and found neither lacking, though if you like your floor to have a seizure once in awhile, you might leave it in the “anechoic” position.  I will say that the “anechoic” setting made mistakes present on older recordings more pronounced.  My Louis Armstrong Greatest Hits CD had some infrasonic noises that made me wonder if somebody was beating on my neighbors door with a wrecking ball.

Regarding . . . Both Satellites (S-150P and SS-250P) 

• The tweeters, though basically the same units used in much of M&K's line, are of their “transmission line” variety.  While they don't actually have open exits in the rear, like M&K's S-1C, the transmission line is “terminated” with an extended, damped chamber, absorbing rear-wave energy, so as to reduce or eliminate interference from otherwise reflected rear-waves with the soft-dome diaphragm, smoothing frequency response as well as allowing better high-frequency transient performance.  The tweeters are also soaked in ferro-fluid, not an uncommon practice, that increases thermal power handling, lending to less dynamic compression.
  
  

• The red LED on the front panels of both the S-150P and the SS-250P is inset via a very precise and straight hole in the front baffle, that makes the visibility of the LED limited to a very narrow window, running a line straight out from and exactly perpendicular to the front surface.  The horizontal dispersion is pretty even across the board, as per THX requirements, but like any speaker with real drivers, there is only one absolutely optimal direction for any speaker, particularly in the highest frequencies, if you can hear them.  With these speakers, that direction is straight ahead.  If you can't see the LED brightly, you're more than a few degrees off axis.  If it's due to a horizontal shift, the sonic difference will be slight.  If it's from a vertical shift, differences can be more dramatic, or just plain wrong depending on the vertical directivity switch (discussed later.)  This LED appearance/disappearance is at first a strange experience, as the LED seems to magically turn on when you get into the direct stare of the loudspeaker, and turns completely invisible otherwise.  But, it's really handy on initial setup to get the loudspeakers properly oriented, as well as during regular use, to remind the listener whether or not they're in the best spot.  The red color and the moderate brightness level allow the S-150P and the SS-250P to provide gentle notice without becoming distracting, even in a dark room.  For those who want to get it even more exact, M&K provides laser sights to align their speakers by aiming at a temporary target in the listening area.  Barry (remember Captain Purple) stressed how critical it was to get the vertical angle of each speaker correct, and symmetrical.  For those without a laser sight, he suggested playing mono hiss between pairs of speakers and adjusting the angle of one so that the image locks in between the two.  From there you can move your head slightly up and down, and the difference in high-frequency output will be apparent when leaving the optimal vertical window.
  
  

• To assist with setup, ultimate speaker alignment, and make the best performance possible that much easier, the ST-Tilt brackets, available for the ST-stands as well as a wall-mounting, and allow very fine adjustment of vertical angle with the twist of a knob.

• To support and anchor the speaker and mount of your choice, the ST-base, available in 25 or 50 lb sizes, connects via a threaded steel pipe which then anchors to the tilt bracket, which in this case bolts to the universal L-bracket, which then bolts directly to both the S-150P and the SS-250P via threaded inserts.  While the robustness of this scenario may be overboard from a purely performance perspective, it's very reassuring in the presence of children or large, not so careful pets.  Should you require an even greater degree of stability, for earthquakes greater than 8.0 on the Richter scale, the bases have threaded inserts that usually serve to hold spikes or plastic feet, but could be used to bolt the bases into the floor directly from below.

• As mentioned, the S-150P and the SS-250P are predrilled, each with 8 threaded inserts on the bottom due to the amplifier section that occupies all of the back, requiring the universal L-bracket.  If you choose to wall-mount, in addition to a universal L-bracket and the appropriate ST-Tilt bracket, you will need a stud.  No, not one wearing a tight T-shirt, but a wooden brace within the wall, or blocking, or very solid brick or concrete.  These things are HEAVY, and as much as I'd like to imagine the look of horror on the face of somebody who mounted the speakers using molly bolts set into sheetrock as they watch the wall fall apart, the altruist in me compels mentioning it.

• The S-150P and SS-250P both mute upon hard turn on.  Not that they get confused and shut up when they get excited, but that applying AC through either a switched outlet or the rocker switch on the back of the units doesn't cause any ugly pops, clicks, or snaps.  So, for those inclined, the units can practically turn on and off via switched outlets with appropriate current ratings through whatever means appropriate without getting nasty on the listener.  The MX-5000 mkII subwoofer, on the other hand, though not vindictive in this scenario, lacks the same etiquette, letting out a bit of flatulence some time after power loss.

Regarding . . . the S-150P

• The Loop-Thru feature, with both XLR and RCA inputs, allows the user, should they choose, to run either a stacked array, complete with dip-switches in the rear to change individual speaker output to allow multiple speakers to operate as a line source.  This could be useful if you've got a really big listening space and need stupidly massive SPL, or if just wish to feed the subwoofer from the same preamplifier output without running a second cable or using a ‘Y' adapter.

• The S-150P has a vertical directivity switch, allowing a more or less directional vertical dispersion pattern.  The primary purpose of the more directional “narrow” setting was originally to limit reflections from things like mixing consoles, but may also be handy in situations where surfaces below or above the speakers create problems with primary reflections.  The “wide” mode is still a little directional on the vertical axis, but far more forgiving, and definitely the way to go if you can't pretty much guarantee that listeners will be consistently at pretty much the same relative vertical angle from the perspective of the speaker, or would like to have the speakers serve background music as well.  The “narrow” mode is critical to within a few degrees on the vertical axis, though both modes seemed to have very even coverage on the horizontal axis.

Regarding . . . the SS-250P

• The SS-250P surround speakers have three modes of operation, accessible though a simple switch on the back.  They can operate as “direct,” mimicking for the most part the S-150P in a narrow vertical directivity mode.  As “dipoles,” putting forth the vast majority of sound through the full-range side elements with primarily a dipolar radiation pattern in opposite phase so as to form a null in direct sound on-axis, with the exception of output from the front drivers to complement an even power response, primarily at lower frequencies.  Dipolar operation creates a sound field more difficult to localize.  And, as M&K's clever “tripole,” The SS-250P mixes a combination of the two other modes, but with a wide vertical dispersion pattern on the front array, to get the best of both worlds- the directionality of a direct radiator, and the diffusive ambient spread of a dipolar speaker.
  
  

• The SS-250P has a ¼” plug labeled "Mode Remote,” which may conceivably allow future runs of the unit to switch modes via voltage trigger or contact closure, something I can see useful for those who can't make up their mind, or prefer different playback scenarios for different purposes, i.e. tripole for multi-channel music, and dipole for cinematic material.

Regarding . . . the LFE-4

• The LFE-4 is a bass management controller.  In other words, the 5 channels of the "5.1" have their bass stripped from them below 80 Hz with a 2^nd order Butterworth low cut filter.  Bass information from those 5 channels is sent to the subwoofer channel, filtered by a 4^th order Linkwitz/Riley high-cut filter.  The “.1” LFE channel is routed to the subwoofer channel output.  The end scheme, both in curve and phase response, is the same as the bass management found in any THX surround decoder set for an 80 Hz crossover point, whether it does bass management in the digital or analog domain.
  
  

• Chuck Back offered up the opinion that in many cases, using the LFE-4 to do bass management instead of a receiver or preamp/processor could result in better sound quality.  This is not the intuitive perspective, as most of us have considered the digital domain the ideal place for bass management, although once I thought about it, you could make a logical though generic argument for analog filters vs. digital ones.  Digital filters, though enabling a whole lot of potential, aren't perfect.  The predominant issue of support for the digital filter is that it can curve frequency response without affecting phase response.  However, the beauty of the THX system is that the phase response of the crossover complements the known phase response of the THX satellites.  Because of this, even digital crossovers in most SSP units emulate the phase response of the analog equivalent anyway.  In addition, when the digital filter is implemented, it must multiply each sample value by a multiplier supplied by the algorithm, and the resulting bit depth is increased.  In other words, to process a 24 bit word with a 16 bit algorithm requires the output to use 40 bits to maintain the original resolution.  Obviously, you can't send a 40 bit signal to most DACs, so it requires dithering down to 24 bits, adding a little bit of noise to encode the information into the lower bit depth.  I don't believe you lose a whole lot of resolution if it's done right, but thought it interesting enough a point to rethink.
   

• Trim pots on the front of the LFE-4 allow very fine manipulation of each channel's output levels, with continuous increments that can make the 1 dB steps offered by most surround processors seem clumsy in comparison.  I used these to set all of my channel levels, but running back and forth from analyzing my SPL meter on a tripod to tweaking the pot with a small screwdriver wasn't nearly as convenient as doing it with a remote and an On Screen Display.
  
  

• The LFE-4 is fully balanced, input to output, though the circuits allow balancing unbalanced signals and unbalancing balanced signals though selective connections on the XLR pins.  Pin 1 is ground, Pin 2 positive polarity, and Pin 3 negative polarity.  When wiring the adapter cable, either in or out, Pin 2 always goes to the hot conductor, Pin 3 goes to the return wire and/or shield drain, as does Pin 1.  If you ever actually end up with an LFE-4, bug Barry about the details.  Otherwise, the easy answer is that the ground path of the unbalanced input or output ties to Pins 1 & 3 one way or another, and Pin 2 goes straight to the hot conductor, or the tip of the RCA.  The value of balanced transmission is better common mode noise rejection, and even if your preamplifier doesn't have balanced outputs but your amplifiers do, placing the LFE-4 right next to the preamplifier allows very short runs of unbalanced interconnects from the preamplifier, so that balanced runs can go to amplifiers that have balanced inputs, perhaps even in another room, with a better chance of making it there quietly.
  
  

• Something of interest with the LFE-4 is the relatively bullet-proof nature of the outputs.  Many of Captain Purple's suggested wiring configurations for connecting to unbalanced inputs shunt the negative polarity output to it's own ground.  I raised the concern that the shunting might result in distortion by taxing the LFE-4, and he said, “If you ever find an LFE-4 which does that, I want you to slap us,” explaining that the negative output would simply drop it's voltage across its own output impedance and run normally otherwise, and the positive output would toodle along none the worse.  Hmmm . . . why can't all electronic components work like that?
  
  

• The LFE-4 has input and output capabilities compatible with the higher +4dBu standard used by the professional industry, as opposed to the –10dBu standard loosely adopted by the consumer industry.  In other words, it can accept substantially higher input voltages and output substantially higher output voltages than most preamps are capable of supplying, higher than needed for most consumer power amplifiers without input trims attenuating the signal.  What this means is that if you've got a handle on signal level adjustments, and have equipment before or after the LFE-4 that can deal with the higher signal levels without degrading signal quality, you can potentially lower your noise floor, even if you run entirely unbalanced connections all the way through.

Setup

I used a combination of M&K's own test CD, the Avia test disc from Ovation Software, and Chesky's DVD Audio setup disc to optimize channel balance, verify complete bass management, and dial in phase and time relationships as best I could.  The most interesting test was Chesky's time-alignment test, which demonstrated the importance of time-alignment for DVD Audio, particularly among the front three channels.

The link below should access a discussion I provided about the option to avoid . . .

Time-Alignment

Anyway, Back to the Setup . . .

Because neither the Onkyo TX-DS989, which has proved a very enjoyable guest nor my Technics DVD-A10 provide any sort of time-alignment for DVD Audio playback, I physically arranged the speakers in an equidistant arc focused at my listening position.  I didn't have enough room to time-align the right rear speaker exactly, and the left rear speaker was actually too close, though I discovered later that setting the left speaker to operate in the dipolar mode compensated nicely, creating multiple arrivals of primarily reflected sound that were as impossible to misalign as they were to align.

When setting levels, I kept the DVD-Audio player and receiver preamplifier outputs at 0 dB gain adjustment, so as to feed equal relative channel levels into the LFE-4 bass management controller, and used the trim pots on the LFE-4 to very carefully tune an SPL match between channels more closely than the receiver's calibration would have allowed.  As bass management was to happen in the LFE-4 following the TX-DS989's preamplifier outputs, I set all speakers to “Large” in both the receiver and DVD Audio player, and let the “LFE” channel remain with the subwoofer channel.

The noise levels with the speakers using the variable input level trim set to the “Reference” position were terrific on the S-150P, but the preamplifier section of the Onkyo, like most receivers, didn't have enough output to make use of the extra input headroom that the variable “Reference” gain setting allows.  When I turned up the gain on the LFE-4, it just turned up the noise from the preamplifier outputs, and noise pickup on the cables between the LFE-4 and the loudspeakers was undetectable, so I used the “Fixed,” THX standard input gain and left the trim pots on the LFE-4 near unity save differences for channel adjustment.  The the background noise level was slightly higher with the fixed "THX" gain setting than the "Reference" Position on the variable input option, and audible within 1 foot of the respective speaker.  Still, the noise level of all three S-150Ps remained incredibly low so as to make any perception of electronic background noise even as close at 3 feet away impossible in anything short of an unrealistically quiet room.

Using just basic twisted pair wire with a foil shield, noise rejection of the balanced inputs was impeccable.  With 30 feet of cable, no cable, or shorted input, I didn't notice a difference.  Should you actually just address the noise of the electronic crossover and amplifier after the input pot, the noise levels get downright stupidly low, where the faint mechanical hum of the power transformer becomes the most audible noise through the lower mid-bass driver, IF you happen to put your ears right on top of the damn thing, with just a smidgeon of standard electronic white noise from the tweeter.  These are the kinds of standards I relish.

The noise levels of the SS-250P seemed to be slightly higher in my house, primarily content related to the 60 Hz AC, and more susceptible to line fluctuations caused by laundry machines, dryers and such, though the noise was not anywhere near audible when listening to music or cinematic material. 

The noise level of the subwoofer, regardless of input gain setting, was as close to non-existent as you'd ever have a need for.  I could only hear the mechanical hum of the power transformer if I put my ear right on the woofer at 3:00 a.m. when everybody else on the block shuts up and turns off their TV.

The SS-250P surround speakers look suspiciously close to the S-150P from the front, which is because they're identical in driver array, with the exception of the four 3” full-range drivers, two on each side, providing the potential for terrific voice-matching under tripolar or direct operation.  I leave out dipolar operation because even though a dipolar speaker may be matched in terms of it's tonal output, what you get is overwhelmingly dominated by the reflected sound, which will vary far more than a speaker which radiates a substantial amount of direct sound.  Anyway, I ran the Chesky pink noise gradual pan between channels, and not only was the blend between the front speakers as identical as you'd expect between identical speakers (I'm a big proponent for identical or as near as identical as possible front speakers), but the pan to the surround channels showed little perceivable difference in my room, any of which was more likely attributable to drastically different locations in the room (high and near the ceiling,) than to output differences from the speakers themselves.  Things were looking good.

I might interrupt to mention something else that many have probably already noticed.  Despite the fact that the S-150P costs more than twice as much as it's passive counterpart, the SS-250P matching surround speaker costs even more.  This is highly counterintuitive for those who've been raised on conventional wisdom, particularly during the early Pro-Logic days, when pretty much any speaker that wasn't complete garbage was considered satisfactory for surround duty, and the wise advice unanimously directed buyers to put the bulk of their speaker budget up front.  Well, while I don't necessarily disagree with the basic concept of that advice, as I do believe that the sound in front is, in general, more important than the sound in the surround field, which is typically reserved for background ambient information, as well as limited special effects with less need for extremely high fidelity, I would still like to raise a few items regarding the performance requirements of surround channels.

First, since the advent of Dolby-Digital and DTS, and even more so with the arrival of DVD Audio, the available media now offers the potential for surround information of equal fidelity between ALL channels, regardless of how it's used.

Second, because of this potential equality or rear channel surround performance, aside from shifting resources to achieve the best bang for the buck toward speakers that we might consider more important, an equally important factor in a loudspeaker system is the systematic match of all components.  Not addressing yet what some may argue as the special needs of surround channels, which really boils down to the compensation for the increased angular spread between loudspeakers, the indisputable best match in rear loudspeakers for a given set of front speakers are identical speakers, be they a “tower” style, a “bookshelf” style, or even those stupid little 4” cubes or balls.  Unless somebody's developed some new economics, it then makes sense that if that's as far as we went, the ideal surround channels would cost the same as the front channels, assuming that we're not giving ourselves a discount for doing without magnetic shielding.  However, if we wish to take into consideration the valid argument that the demands of the surround channels are in fact more difficult from the perspective of filling a larger angle with a smooth and consistent sound field without compromising the performance we've already committed to up front, we need to put even more resources into addressing the additional requirements due to the increased angular spread and Voila, it actually makes sense.  Is spending more on rear speakers than front speakers a good bang for the buck decision?  No.  It ceased to be a bang for the buck issue long before the price of any loudspeaker/amplifier combination tops $15,000 before tax.

Subjective Impressions

Assuming a reader might have any interest in my personal, subjective opinions, I should probably get to my listening observations.

Do I Like this Whole Setup?  Oh, Man, Do I!

I should begin with a back pedal, just to put things in reasonable context, and prefix this shower of praise with the statement that loudspeakers, even between those of which you'd qualify as objectively accurate by whatever standards you can muster, vary greatly, and preference between listeners can be highly variable.  That said, I can confidently state that I've come to value my own subjective opinion as much, and usually more, than anybody else's I've met, or read about.  I hope everybody else holds the same value of their own opinions.  Having put that whole non-committal garbage out of the way…

In terms of basic character, the active setup isn't far off from the passive S-150, as we'd expect with identical drivers, similar crossover curves, and the same driver layout.  This similarity is a good thing.  Had it sounded dramatically different from the passive counterparts I've come to appreciate, I'd have packed the active system up 15 minutes after turning them on.  Like most if not all M&K speakers, the S-150Ps sound very smooth at the top end, but open and lively as opposed to reticent or laid back.  Not a bubbling kind of sparkling like a Canton or JM Lab, but definitely offering very good extension so far as I could notice in the extreme treble.  The midrange has the same kind of plain, definite, yet not pushy presence that has become one of my pet needs for permanent residency.  Not overbearing but certainly there.  Full, but not sluggishly warm, or as JJ likes to say, chesty.  The mid-bass is tight, but not anemic or thin.  For me, the overall sound is very much Baby Bear's porridge.

If I ever whip out “tight and tuneful” in a context feigning seriousness, please pelt me with my own snot. 

The MX-5000 mkII was, err . . . deep?  While my listening room's modest volume of more or less 2500 cubic feet doesn't make truly deep bass a very difficult task for any respectable subwoofer with an iota of extension and a gradual roll-off, once I put the work into finding the right location, and the best combination of laundry baskets and book-filled plastic storage bins scattered around the room, the MX-5000 mkII actually startled the hell out of me.  Does that make me angelic?  Although I had heard JJ's original MX-5000 years ago, the memory wasn't fresh, and the MX-5000 mkII immediately reminded me why JJ had nicknamed it, “The King of Slam.”  I've heard a few subwoofers that put out more extremely low frequency energy than the MX-5000 mkII, but when it comes to sheer ease and authority with dynamic transients, peers of the MX-5000 mkII are on a very short list.  That it can achieve the kind of output it does without significant perception of compression lends validity to M&K's claim that their “Headroom Maximizer” circuit may indeed be exceptionally transparent, or at least tricky.

I ran a quick sweep down to 20 Hz, and not surprisingly, in either the “Anechoic” or “THX” mode, extension went down without any signs of letting up.  The Avia disc that provides the sweep doesn't provide signals lower than 20 Hz (that I've stumbled across so far, but I'm sure David Renada will smack me if I missed it.  Some day I'll break down and give that guy a hug.)  That's not to say that the MX-5000 mkII is technically limitless.  Aaron Hodges came over in the middle of some of the low frequency sweeps, as I tried to twiddle around with placement and furniture.  In the mood to be obnoxious, I repeated the sweeps at louder and louder volumes, and after while, I could get the subwoofer to audibly distort, but it was a bit difficult to tell, as I had to put my head right next to the drivers, lest the rattling and shuddering of the entire house drowned out the distortion from the sub.  Safe to say, for my use, the output of even just one sub seemed plenty, even if the thought of two subs usually makes me a little cozier.  Those who really want more raw output are free to pick up a second, or a fourth.  Hey, don't laugh.  I wasn't kidding.  Even at almost $3k a Popsicle, buying 4 subs at three thousand a piece is less ridiculous from a performance perspective than paying for a single subwoofer at $12,000 or more.

Anyway, Overall . . .

Although it's difficult to gauge which speakers truly have the “correct” tonal presentation in any given room, having listened a whole bunch to a whole bunch of stuff, I've developed handle on what I like, and what I trust.  To me, the S-150P and the SS-250P are much like the classic S-150, in terms of lacking much discernable commentary on presentation, laying out details explicitly enunciated, but without particular emphasis in any part of the frequency spectrum.  Narrow frequency dips are hard to detect, but sharp frequency response peaks, though sometimes lending a sense of dynamic snap, or a fine razor's edge to the perception of detail or “air,” are easier for the careful listener to identify and eventually tire of.  Thankfully, I haven't noticed such irritations in either the S-150P or the SS-250P.

And, also like the S-150, the powered counterparts concede the involvement of playback to the recording itself, as opposed to providing substantial loudspeaker-induced enhancements.  Some perfectly enjoyable loudspeakers do in fact provide more excitement, warmth, depth, or clarity than the recordings actually contain, and while that may prove very fun and entertaining in some cases, it inevitably detracts from recordings which merit playback as is.

In terms of how active drive benefits the end user more than the passive equivalent, what then is the advantage?  If you've heard S-150's with top notch equipment behind them, and just as importantly, after careful setup, you probably know the rare blend of excitement, finesse, neutrality, clarity, and the sheer uncloaked window into the history of what happened and followed the recorded event, be it acoustic space, proximity to the microphone, the implementation of artificial reverb, the use of analog tape, noise gates, compressors, and any other path from the source through the mixing and mastering chain.  When the whole recording process turns out well, and the playback system locks in, the end result shows, and it's fantastic.

The “P” versions provide just a little more of everything that the passive units excel at- a bit more ease in dynamics, a tad more openness in the sound stage, a slightly greater discrepancy of fine detail, and a truthfulness that actually transcends realistic to remain real, beyond "recreating live music," reproducing the recording itself.  There is no chicanery, and to be honest, a lot of people won't like what these speakers don't do to the sound.  For the listener trying to make their entire collection sound “good,” there's bound to be some initial disappointment. If the recording sucks, it'll sound that way.

However, after trying very many flavors of loudspeakers, I've come to consider this kind of brew the best long-term solution for my own needs.  I'm willing to let a lacking recording lack to get the most from the best of them.  The S-150P/SS-250P combination may reveal flaws indiscriminately and without mercy, but also do so without malice.  They're not overtly aggressive, and so offer an intellectual perspective to dissect methodology, characterize the nature of sonic textures, and consider where the producers or engineers might have done better while maintaining the capacity to immerse a listener in an enjoyable, if not believable, illusion.  The analytical abilities of these speakers may compromise mediocre recordings by showing them as they are, but when the performance and the subsequent processes leading to the disc really nail it, look out!

Specific Anecdotal “Evidence”

Cinematic Release

The sound quality of most movies isn't fantastic from a fidelity standpoint. They do often offer good music and occasionally real sounds within the effects, and can still be a pleasure to listen to, guilty or not.  What they're really good at are synthetic explosions.

"Pearl Harbor" - While the story is drawn out, overly simplistic, and of little value other than, uh . . . I didn't really buy the movie for a plot.  What I really wanted was just one long bombing scene, and that I got.  When it came to the large bombs, the results via the MX-5000 mkII were without exaggeration, seismic.  It would be hyperbole to claim that it collapsed my lungs, but it certainly didn't shy from the frequency content, and conveyed the intimidating sense of power and respective helplessness without any indication of serious challenge.  The planes and guns were good for a tingle too, with great pans and loud bangs for the whole system to engage a listener without straining or apparent compression.  Realistic?  I have little experience with machine guns or 500 lb. bombs, and hope to keep it that way.  Startling, without a doubt.  When I could bring myself to pay attention to the dialogue, it sounded clear and natural, though not emphasized as much as by some other loudspeakers that actually make dialogue just a bit “clearer” by peaking up the upper mid-range or lower treble.  While colorations in such loudspeakers can make muffled dialogue easier to understand, sibilants become exaggerated and often annoying, so I'm happy to do without flavorings.

We also watched "Jimmy Neutron", went back to "Antz", and toyed around with "Gladiator".  The greatest complement I can give is that I didn't spend much time listening because I had only to hear the soundtrack.

Plain old CDs

Miles Davis' "Kind of Blue" is a great example of a mixed bag that remains a pleasure despite the identifiable characteristics of recorded sound.  The textures of drum skins, horns, as well as the softness of individual notes in context of melody, each distinct and obvious within an overwhelming analog feel and distorted proportion of the original recording medium and methods.  It was an interesting album to listen to with the M&K system in that you can hear simultaneously how recorded it really was, but also make out so much of the nature of individual instruments.  While many loudspeakers might blend the components into a more whole, believable presentation, I appreciated the ability to resolve what's actually on the disc.

Sara McLaughlin's "Surfacing" is another showcase of an album that falls short in some aspects but offers so much in others.  Though the first song I heard of hers, Building a Mystery, I've yet to warm up to, I really love her voice, and the rest of the music on the album, such as Witness, isn't bad either.  The recording doesn't present anything like Sara standing in any kind of room I've been in yet, but provides a terrific means for the S-150P to engage in storytelling, complete with the closer than close presentation of vocals, almost warm to the touch, as well as an exaggerated but effective low frequency pulse, with which the MX-5000 mkII flowed, fluent and majestic.  While this whole loudspeaker setup did nothing to hide the fantastic, over-magnified nature of the album, the blatancy of the playback let me enjoy it for what it was, a wonderful embodiment of fancy.

Eric Clapton's "Unplugged” album, a “live” recording, is a lot of fun, particularly with extraordinary bass prowess on the playback side.  The low frequency content is artificially pronounced, but does supply the illusion of an expansive and limitless presence to the performance, pretty much taking over the room.  In this respect, the MX-5000 mkII earned its laurels, pumping and thumping without ever hinting at its own effort.  The more audible, higher frequency portion of the album also has a lot to offer, and the S-150Ps did a great job conveying the throaty body of his voice, the percussive friction of his guitar strings, and even the slightly removed clatter of the audience.

Chris Issac's "Heart-Shaped World" has a variety of good and better, though the most mesmerizing track, from a recording standpoint, is for me Blue Spanish Sky.  There is nothing real about the depth of sound stage that seems to extend both back and beyond the speakers, nor the floating voice that flows in a sea of reverb, but the daydream is absolutely delectable, and unequivocally seductive.  In the context of the playback system, what this M&K setup does far better than most- simply get out of the way, like the sonic image from good headphones pulled out front.

DVD Audio

Aaron Neville's "Devotion" DVD Audio disc- I never really considered myself a gospel fan, but Jesus…  Like many audiophiles, my pursuit of good recordings inevitably introduces me to good music, and forces me to expand my horizons.  I'm not really fond of all the tracks, or even half of them, but this album has more than a couple sincerely enjoyable pieces, from an audiophile perspective, as well as simply from the point of a music lover.  With Mary Don't You Weep, this setup allows a wonderfully discriminating portrayal in mixing differences between lead and background vocals, both in depth of sound field and artificial reverb, as well as the acoustic character of the vocal capture itself.  Somebody did a fantastic job with this DVD Audio disc, putting together a continual integration of ambiance without bloat and precision without incision.  These active loudspeakers excelled and showed every facet of the gem.  As good as that recording is…

Gordon Goodwin's "Big Phat Band" is quickly becoming one of my favorite albums, let alone one of the most precious of my small DVD Audio collection, and not just because the wife finds the music annoying.  Like Aaron Neville's “Devotion,” it is certainly a studio mix in character, and a ripping good one at that.  To quote Goodwin, this is, “the punchiest and cleanest big band recording I've ever heard.”  Everything from the primeval punch of the kick drum, to the blaring, quickly shifting discharge of a horns, or the snap of an electric bass, just jumps out.  While the recording does make extensive use of the surround channels, justifying potential expenditures on superior surround speakers, it also does so tastefully, providing an enveloping effect that seats you in the midst of the band.  Throughout the album, but especially on tracks like Sing Sang Sung and There's the Rub the bass quality of the MX-5000 mkII, in terms of depth, dynamics, and all around composure, earns thorough and superb accolades.  In the case of the latter track, the rolling and plucking electric bass prompts the MX-5000 mkII to deftly smack the gut while it massages the pants.  The S-150P and SS-250P come through the grueling workout of complex transients, dynamic gymnastics, and such a variety of detail throughout without a hint of glazing over.  Atta boys!

Chesky's "Ultimate DVD Surround Sampler and 5.1 Setup Disc" is terrific for calibration and optimizing your DVD Audio playback.  However, it's got some kick ass music as well.  To really get the most from the medium, you'll have to go the route of sending your “center” and “subwoofer” channels directly to extra side channels for what Chesky refers to as “6.0.”  I couldn't figure out a way to get that to work with the LFE-4 bass management controller as is, didn't want to bother with switching for just one disc, and I'm as lazy as I can manage anyway, so I selected the 4.0 channel option from the DVD-Audio disc's menu.  Not bad for a compromise.  Bucky Pizzarelli's Lime House Blues wasn't my favorite piece musically, but still fun to listen to, and puts you right in the middle of a club.  The Conga Kings' Tumbao De Tamborito  was an absolute pleasure, pushing me to move along with the expansive spread of a sound stage, feeling like I was watching the percussion ensemble a few feet away on stage.  Carla Lother, singing Captain Courageous, not only had a nice voice to complement a bass line that I could hear shuddering her air while it quaked my own, but kept making me think of Captain Purple, which can be a very good thing for those who can keep it to themselves.

Rounding Out . . .

There is a level of composure that a professional audio reviewer should demonstrate.

Luckily, I'm nowhere near a professional audio reviewer, nor do I wish to be.  When it comes to the luxury of time that I can dedicate to my work with Secrets, professional is nice, but what I really dig about the gig is the chance to openly speak my mind, with just a little editing by the crew to make my choice of language presentable.  Even though I realize that statements of unrestrained enthusiasm provide fodder for an embarrassing reprint taken out of content, I must lay my excessive pleasure flat out on the table.

With the qualification of an outstanding recording and reasonably good front end, the first of which I concede is itself an exceptional thing, here's the gratuitous truth:

Of every loudspeaker/amplifier combination I've had to review to date, the M&K S-150P/SS-250P/MX-5000 mkII active loudspeaker system is by far, hands down, without near peer, the indisputable champion, without a contender in sight.

Granted, opinions vary, what works in my home won't necessarily work well in somebody else's, and the portion of what I've actually brought into my home is also only a fraction of the total products available.  All true, and all equally good excuses to discount any of this shtick as worthless.

I would even go on, however, to even say that when backed up and armed with the best DVD Audio recordings available, the M&K active setup, when dialed into it's best, provided some of the best audio I've ever had the pleasure to hear, period, and that includes some of the most expensive theater and music systems around.

Okay, I might lean a little towards a full Meridian 800/861 system feeding a full set of DSP-8000 digital loudspeakers when that option comes along, but it hasn't, and I don't see my pocket book performing any perpetual income tricks in the immediate future. 

Do I honestly think that the M&K active setup can equal every truly cost no object audio system?  In a every field?  No.  There are very expensive loudspeakers that can play louder to the point of even more ridiculous SPL with truly superb sound.  The particular models I have in mind, which offer, in my opinion, an equal sonic performance in other areas go for about $70,000 a pair, and would be a pain in the ass to use with a truly a matched center standing over six feet high.  I also feel that their top-end is just slightly less neutral than the M&K system, even if it is alluring.

There are speakers available at comparable prices that are just a sliver better when it comes to soundstage imaging, and in my opinion of equal tonal neutrality, but they can't compete when it comes to real dynamic range.

There are subwoofers for not much more money, or even cheaper, that can exceed the already substantial raw, continuous output capabilities of the MX-5000 mkII at the very lowest limits of hearing, but often suffer their own self-control to do it.  When it comes to convincingly integrating with “satellites” that absolutely require higher crossover frequencies in the 80 Hz - 100 Hz range, It's difficult to find a peer to an M&K sub.

So, while I must concede that the M&K S-150P/SS-250P/MX-5000mkII may not be the absolute best loudspeaker/amplifier system available for any given person given variations in personal taste and the subsequent weighting of different performance parameters, when it comes to competing as an all around package, it can hang with any of them.  If you're looking to throw incredibly vast amounts of money into a system to obtain great performance, there are many products far more efficient at absorbing finances.  On the other hand, if you are willing and able to sink what I consider a sizable chunk of cash and effort into some playback hardware, even if you can spend multitudes more, I'd offer this M&K active system as one of the first to evaluate.

From the bang/buck camp, for which I still carry a membership card, the question remains, “Is the performance difference worth the additional cost of the active units versus the passive S-150 and matching surround speakers?”  Whether anything is “worth it” really hinges on the answer to the question, “Worth it to whom?”  Strictly speaking suggested retail, $2,500 will get you a really terrific outboard amplifier to power the front three speakers, another $2,500 will get you a matching amplifier for the next 2 channels to round out what I consider a sizable but realistic budget for extremely high-quality power amplification, capable of 400 watts/channel into each loudspeaker simultaneously with great audio performance at any output level.  Three S-150s will run $2,625.  Two Surround-250s will cost almost $3,000.  Add that to the $2,900 for the sub, and we're talking $13,625 for an absolutely splendid amplifier/transducer combination.  The equivalent fully active setup of three S-150Ps, two SS-250Ps, and the same sub rounds out to $15,500.

Is the performance superiority of the active system worth the extra $1,875 to me?  Absolutely!  I'm currently trying to scheme how to shuffle my financial and equipment resources so I can sew my name tag onto as much of this system as possible while minimizing current equipment loss and/or couch time.  Hey, if my kids are willing to watch "Ice Age," "Harry Potter," or whatever contemporary cultural enrichment parents can provide through online purchasing, isn't it my obligation as a parent and legal guardian to provide the best and most honest presentation possible?

Complaints

Not done yet.  I just need to have some gripes, lest my comrades needle me at CES as too easily impressed.

In addition to the SS-250P not being as immune to line noise as the S-150P, which may have set unreasonable standards to begin with, the XLR connector that comes with the balanced input option of the MX-5000 mkII doesn't have the locking release tab that all the other XLR inputs have, meaning that it doesn't click in, and so can be pulled out without complex finger manipulation.  My problem isn't from a sonic performance standpoint, but rather that my very cute and mischievous toddler rewards herself for a hard day's drool by pulling the XLR connector out of the subwoofer and sticking it in her mouth.  There's not enough voltage out of the LFE-4 to make her tongue tingle (I think,) but it's just gross, and almost as irritating as when my wife puts mail, a cup of tea, or her elbow on top of a functioning loudspeaker.