Quick and Easy Upgrade to Mk402 Speakers

Dayton Audio recently announced two budget speakers in their product line up, the MK402 and the MK442. The MK402 is a 2-way ported design with a 4" midbass driver and .75" soft dome tweeter and sells for a meager $69/pair. The MK442 steps it up with an additional 4" driver in an MTM driver topology along with a more sophisticated crossover network and again sells for only $100/pair. In this review, we take a look at both speakers to better understand what type of performance to expect for what amounts to a cost less than most audiophiles spend on speaker cable.

The MK402 is a small speaker designed for systems where space is at a premium and a subwoofer might not be in use thanks to its 60 Hz extension, which is unusually low for such a small speaker. Scenarios for such a product would be a desktop stereo system, a small system for a shelftop in an office or bedroom, or a bedside system. It is intended for setups in close proximity to the listener, and it looks like it would be a good fit for a system with simple electronics, i.e., a small amplifier and no bass management. Dayton Audio is positing the MK402 as an affordable yet still high-fidelity speaker by stressing its heavy-duty woofer, chamfered edge baffle, a crossover that is more than just the barebones high-pass filter ("more than just a Capacitor" says Dayton Audio's literature), and ¾" soft dome tweeter. The MK442 is its corresponding center channel speaker. So how well do the MK402 and MK442 accomplish their mission of being small speakers with meaningful bass extension and high sound quality for their low cost? With the pair of MK402s and a MK442 that Dayton Audio has sent us for review, let's now try to answer that question.

Unpacking and Appearance

The MK402s and MK442 came packed in a cardboard box with two thick foam pieces sandwiching the speakers which protects them from shock and gives them space from the sides of the box. They were wrapped in plastic for protection against moisture and scuffs. The packing was reasonably good considering the cost.

These are not bad looking speakers. They use a textured black vinyl finish that, combined with their chamfered front baffle edges, do project some sense of style. The grilles do hide the drivers, but that makes the speakers look a bit more plain. The glossy black tweeter and beefy surround on the woofer along with its concave dustcap give the MK402 and MK442 speakers a somewhat brawny look for small speakers. With the grilles off, they are just begging to blast some tunes; the grilles give them a more sedate appearance.

Design Overview

The MK402 and MK442 speakers are a nearly textbook case of getting a full sound out of a small size. The key component in this goal is the woofer and its bass extension ability; it will need some specific qualities towards achieving this end. But before we get into the woofer, let's talk about the MK402's diminutive size. At 9.5" high, and about 6" wide and 7" deep, it is on the small size for bookshelf speakers. It isn't enormously heavy either, at 5 lbs. It's a bookshelf speaker that could fit on many people's desktop setup. That small size does have a penalty; it doesn't get as loud for the same amount of electrical current as a larger speaker would, all other things being equal. The MK442 should be a bit more capable since it has two woofers.

Dayton Audio claims the MK402 and MK442 has usable bass down to 60 Hz, which is quite a feat from a 4" bass driver. However, the bass driver used in these speakers is rather heavy-duty, considering the cost of the speakers. It is the Dayton Audio TCP115-4. It has a relatively low resonant frequency for such a small cone with a stated Fs of 53.8 Hz. Its beefy motor uses a ¾" tall, 3" diameter magnet with a vented pole piece. The voice coil is a 1", four-layer CCAW (copper-clad aluminum wire) wound around an aluminum former for better thermal dissipation. Its suspension system uses a 3" diameter spider along with a ½" wide surround; a very brawny surround for a 4" woofer! The cone is made from treated paper with an inverted dustcap. It looks to me like the bass driver forms the heart of this particular speaker; it has the sort of build quality that I would expect to find in a speaker at twice this price.

Editorial Note: Hoffman Law for Speakers

Small speakers don't usually produce much bass as a consequence of their size and the laws of physics. The large wavelengths of air pressure waves in low frequencies require a lot more air displacement than higher frequencies to maintain the same loudness level. This is why tweeters are small and bass drivers are large. A driver with a small woofer diameter would have to compensate for its small size with an ability to move large distances in order to reproduce significant bass; breadth is replaced by depth in order to achieve the same displacement of air. The drawback of that is the moving components of long-throw, small diameter woofers must necessarily be relatively heavy, and that weight penalty means it takes a lot more energy to move the driver to achieve the same loudness levels.

That is related to a rule of thumb within the speaker industry called "Hoffman's Iron Law" (named for Anthony Hoffman- the 'H' in KLH speaker company name) that states a speaker can have only two of the following but never all three: low bass extension, high-sensitivity (sensitivity meaning how efficiently does the speaker turn electricity into sound), and small enclosure size. A speaker that has high sensitivity and real bass ability has to be large by necessity. A speaker that is small but has high sensitivity will not have any real ability to reproduce bass. And a speaker that is small but also has significant bass extension will not be very sensitive- and this attribute is the trade-off that Dayton Audio makes with the MK402 bookshelf speaker and MK442 center speaker.

MK402 crossover (left), MK442 crossover (right)

The MK402 and MK442 both use a ¾" silk-dome tweeter with ferrofluid cooling (the Dayton Audio TD20F-4). Such a small diameter tweeter should have wide dispersion even at very high frequencies. The MK402 speakers use a four-element crossover network with a 2.5 kHz crossover frequency: an inductor and capacitor are used for a 12dB/octave low-pass filter on the woofer, and a capacitor is used for a 6dB/octave high-pass filter on the tweeter. There is also a resistor intended to pad the tweeter since the tweeter has a higher sensitivity than the woofer. The MK442 uses a more sophisticated 8-element crossover that has four capacitors, two inductors, and two resistors for an 18dB/ octave slope high-pass filter on the tweeter and a 12dB/octave low-pass filter on the woofers.

The cabinet is made from ½" thick MDF paneling all around with no internal bracing. Internal bracing in such a small cabinet is probably overkill, so the omission of bracing here isn't a worrisome matter, especially at this price point. Both the MK402 and MK442 are rear-ported with the MK402 using a 1" diameter port and the MK442 using a 1.5" diameter port. The ports have only slight flaring. As was mentioned previously, there are some chamfered edges on the front baffle, but this appears to be done more for the sake of style than to reduce baffle diffraction because it still leaves quite a bit of surface surrounding the tweeter which is where diffraction would be at its most severe. The interior is stuffed with a good amount of polyfill to damp backwaves and also for isothermal conversion (isothermal conversion turns acoustic energy into heat to make the enclosure seem a bit larger than it actually is).

The grilles use a ½" thick sheet of MDF with cut-outs for the drivers and covers everything in an acoustically transparent fabric. It is attached to the front of the speaker with plastic pegs. A grille like this, which essentially protrudes from the front baffle in front of the tweeter, is bound to cause extra diffraction which isn't going to do the sound any favors. It is there to protect the drivers and make the speaker look more innocuous. Four small, soft rubber discs serve as feet. The softness of the rubber here is a good idea for damping since this small speaker has a relatively long-throw bass driver that can play to such low frequencies where rigid feet would likely cause audible vibration on a hard surface.

Taking a step back from an assessment of individual parts, the small diameter of the woofer and tweeter suggests that the MK402 and MK442 should have a very wide dispersion; in other words, the speaker should be able to project sound outward at a very wide angle, so there won't be a small 'sweet spot' or a restricted area where the speaker sounds good. If the response of the dispersion is smooth and even, then the speaker should sound good nearly anywhere in front of it. It is also a speaker that attempts to squeeze real bass frequencies out of a small container which is never an easy feat. We will look at both these aspects when we examine its groundplane low-frequency response and also off-axis response measurements.

Listening Sessions

In my approximately 24' by 13' listening room, I set up the speakers with stand-off distances between the backwall and sidewall, and equal distance between speakers and listening position, with speakers toed-in toward the listening position. Listening distance from the speakers was about 6 feet. Amplification and processing were handled by a Pioneer Elite SC-55 AV receiver. No room correction equalization was used. At times, subwoofers were used to supplement the bass, mostly using a 100 Hz crossover frequency.

Music Listening

Diana Krall sounded legitimately good on these $70 Dayton speakers!

I started off with some vocal music since an errant reproduction of the human voice is fairly easy to detect. I borrowed a CD copy of "The Very Best of Diana Krall" for this purpose. Diana's voice sounded vibrant and rich, and I did not sense anything amiss. Imaging was very good, as good as I have heard on much more expensive speakers. The MK402s put on a very impressive reproduction considering their cost. The MK402s caught all the bass that this album had to offer as well. While the bass wasn't as powerful as it is with subwoofers, it was clean and was not overly-emphatic on any particular group of notes. This album sounded legitimately good on these $70 speakers! I then threw in Madonna's "Immaculate Collection," a CD I have heard many times and was very familiar with. Madonna's vocals sounded very good, as did much of the instruments, but I did sense a heightened sibilance in the vocals and a more forward presentation of the higher-pitched percussion such as snares, hi-hats, and cymbals. I repositioned the speakers to have a strong toe-in angle, which put me about 30 degrees off-axis with the speakers' aim crossing well in front of me. I reasoned that a speaker with a small diameter tweeter like the MK402s would have a very wide dispersion, so a more severe toe-in would be needed to make a real difference in the sound. I found this toe-in did soften up the sound a bit and made it less fatiguing, although the treble still seemed somewhat elevated.

I turned to orchestral music with more complex instrumentation to see how the MK402s would handle denser passages. One disc I listened to was the deluxe edition of the original soundtrack for "Aliens" by James Horner, a famous score which really needs no introduction. The MK402s proved to be deft with this material. Brass had a vivid shimmer, tympanies had a convincing thud, and the string sections provided an unsettling melody for the more tense passages. Instruments had reasonably good separation. As with the Diana Krall album, imaging was surprisingly good. The MK402s could get adequately loud in my theater room, but I didn't push them too hard. There is only so much wattage a small bookshelf speaker can take before the woofer is beaten to death or the tweeter starts smoking. So, I did not push these to reference levels. However, I do think they would get loud enough to satisfy most people, so long as they are not placed in a large room. Subwoofers would help out in this respect as well, by greatly reducing the excursion needs for the small 4" woofer. Since I have subs located throughout the room, I was able to set the crossover point higher than 80 Hz without having bass localization issues, and such a high crossover point is undoubtedly beneficial for a small bookshelf speaker like the MK402.

I decided to go for something that could push the system more with a higher crest factor (ratio of peak value to RMS value in the waveform, i.e., it's more continuously louder) than orchestral or lounge music, so I brought in Juno Reactor's "Beyond the Infinite". This is an energetic techno album with world music influences from 1995 (I bought this not long after it came out, but it doesn't feel like it was that long ago- am I getting old?) "Beyond the Infinite" has a production quality that exceeds that of typical techno music, but still keeps things boisterous and fast. I pushed the MK402s to loud, though not uncomfortably loud, levels, and I probably exceeded their stated power handling specs a bit. But, they did not lose their composure and sounded clean and strong throughout. I used subwoofers for most of this album, and when I did switch the subs off and ran the speakers full-range, they did struggle by running into some audible port turbulence and distortion. However, while they can stay clean at relatively loud levels, they are most certainly not party speakers. I did not try to push them to club-loud levels, and they wouldn't have survived long if I did. While they can probably get loud enough for most people, these speakers are not going to satisfy head-bangers.

I should also note here that I tried the MK402 speakers in the near-field as speakers for my desktop PC setup. Some bookshelf speakers do not hold their far-field sound in the near-field and so do not sound good at this close distance. I would have guessed that the small form-factor of the MK402s would be beneficial for listening at this distance, and I was right. The MK402s image very well in the near field. I kept the aggressive toe-in angle that I used in my home-theater system to alleviate the heightened treble and listened to a variety of content, mainly music, computer games, and television shows, and I enjoyed the MK402s as desktop speakers. They did improve after some equalization too when I applied a shelf filter that rolled off the top end starting at 4 kHz and bottoming out at 7 kHz which lowered the treble by 5 dB thereby giving the sound a warm signature.

Movie and Television Listening

To gauge how well the MK402's and MK442 deal with dialogue intelligibility, one program that I watched with them was the first two episodes of the second season of HBO's "True Detective" series. Season two of this very dark noir series was not as well received as the classic first season, but I contend that it is still a terrific watch and, for me, very absorbing and atmospheric. I think it is a good trial for dialogue intelligibility because of how abridged and elliptical the dialogue can be at times even though it is well-recorded. Music is also beautifully recorded and has some folk music performances in a grim and sad style that compliments the show. Of course, the MK442 center will carry the burden of a surround sound mix in "True Detective," and I can report that it executed the dialogue well. I did have to lower the gain considerably on all of the surrounds and subs since they were set for speakers that were much more sensitive than the Dayton Audio MK speakers, but once that was done, the system sounded very good as a whole. The dialogue was clear as were effects sounds and music. I have been looking forward to re-watching the second season of "True Detective" and am glad that I could do it with speakers that can render it as naturally as these.

A movie that I watched with the MK speakers was the 2011 science-fiction thriller "Source Code," a very polished and highly-regarded film that has a sound mix with a good balance of dialogue, effects, and music (if you haven't seen this under-rated movie yet, do so immediately). Much of the movie is set aboard a train with stretches of dialogue and tense music punctuated by bomb explosions. The high production values and frantic pace of "Source Code" make it a fine choice for evaluating a sound system. The MK402 and MK442 speakers reproduced "Source Code" very nicely. If I didn't know, and someone had told me the sound that I heard during "Source Code" was coming from small bookshelf speakers with 4" woofers, I would have been very surprised. It should be kept in mind that, at a six-foot distance, I did have them placed closer to the listening position than the ten feet distance that I normally give speakers, but that is the kind of concession that has to be given small speakers to retain a good dynamic range. The farther these speakers are away from the listening position, the greater the disadvantage they will be at for reproducing loud sound cleanly.

Additional Listening With the MK442s as an Upright Pair

After measuring the acoustic behavior of the MK442 in free-air testing, I was quite impressed with its behavior on its vertical axis. From the response I measured on its vertical axis, I reasoned that the MK442s would make for an exceptionally good speaker when used on its side. I asked Dayton Audio to send me another MK442, so I could listen to them as a stereo pair in that orientation. As the measurements suggested, these sound very good when used standing on its side for a vertical alignment of the woofers. They had excellent center imaging and a good spectral balance. While just a tad bright, they were easier on the ears than the MK402s, and I did not feel the need to equalize them or use a hard toe-in to alleviate the treble response. They sounded good right out of the box. From listening and comparing a pair of MK442s to a pair of MK402s for stereo music listening, I think that the extra cost for a pair of MK442s is well worth it. The MK442s sound good without even considering cost and without adding any caveats or conditions. When considering that they only go for $100 a pair...well, I am listening to a pair as I type this, and they are astonishingly good for the price.

Jon AA posts on August 27, 2019 21:31

Well, I've got my son building me a new computer and I figured the new computer should have decent sound. So I ordered the DTA-2.1BT2 100W 2.1 Class D Bluetooth Amplifier + MK402X 4" 2-Way Bookshelf Speaker Pair + The MKSX4 Four 4" Driver Low Profile Passive Subwoofer.

I started out planning to just get the MK402BTX speakers but like usual, I talked myself into spending more. I figured with the amp I'll have more power, sub output and a tone control and if I want to change speakers in the future I can use anything I want with it. The sub looks perfect to put on or under a desk somewhere and should really take a load off the little speakers and should improve the overall sound quite a bit vs. expecting desk sized speakers to have adequate bass.

Should be one heck of an upgrade compared with the tiny little computer speakers I've been using all these years. Thanks for the review on these, I don't think I would have chosen these otherwise.

Adam2434 posts on August 24, 2019 12:39

If my math is right, the 18V 2A power supply can only deliver 36 W. Assuming 90% amplifier efficiency, that would translate to 16.2 W/ch. Sound right?

Plugging 16.2 W/ch into this Peak SPL calculator, I get the numbers below at 15 feet and 3 feet. If all these numbers are pretty accurate, they confirm my observations that these speakers get plenty loud nearfield and loud enough for background music at 15 feet. When testing them in my garage, at about 15 feet away, they got as loud as I would want to play in the garage…any louder and I might bother the neighbors.

Net, these speakers make a nice sounding, inexpensive, compact system for background music in a garage.

Doing better for the money ($100),IMO, would require scoring deals on a used receiver and a good pair of used bookshelf speakers for $100 total. This is totally possible if you have the "eye" and patience - I have done it several times! In fact, I'm currently also playing with a $6 Onkyo TX-8211 50 W/ch receiver and a $70 pair of Polk RT35i in the garage. This system sounds "bigger" than the MK402BTX (because it is),but the MK402BTX hold their own at moderate levels.

Edit: for some reason, some spaces were lost after commas. Not sure if this is a common issue on this forum.

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Adam2434 posts on August 23, 2019 13:54

I'd be curious to know the actual max w/ch vs. distortion and SPL the powered MK402BTX can do.

The specs are attached, but it's hard to tell what they really mean. My best guess is that the internal amp provides 20 w/ch RMS at <0.7% THD+N.

A distortion vs. SPL level test would be cool (as well as a frequency response test to determine if the new crossover delivers).

I'll lend my pair to Audioholics for a test.

These little "Mighty Mites" will do moderate background and nearfield levels just fine.
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Source: https://www.audioholics.com/bookshelf-speaker-reviews/mk402-and-mk442-review

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