New & Reviewed

Built & Tested: Mini Monitor Kit

Daniel Koch

Issue 28, November 2019

We get the tools out to build this speaker kit and see if the audio performance is as good as many online reviews claim.

Not so long ago, as recently as the early 2000’s, speaker kits were still commonly seen on retail shelves. The science of speaker design was still popular, while materials and components could be purchased individually without having to drive to a capital city or purchase by mail order, which hadn't been supplanted by internet ordering yet.

The increasing popularity of home theatre systems, large-format televisions, and home cinemas shifted the focus from pure audio quality to high-impact sound that lacks much of the finesse of a quality music system. Subsequently, digital sound formats have improved, but the trend was still towards factory-produced systems with small speakers, leading in turn to the prevalence of soundbars that we currently see on retail shelves.

So what does an audiophile do? Where does one go to find speakers from a previous era? These speakers, suitable for high-quality music or well-recorded cinema, as opposed to mainstream TV and streaming service transmissions, have been hard to come by. The answer comes from niche online suppliers such as The Loudspeaker Kit. The online platform allows these sellers to viably supply a market which is dedicated, but not big enough to support a bricks-and-mortar distributed retailer.

The LSK-M4S speaker kit, which arrived on the DIYODE workbench recently, sparked some interest on the back of the performance of the pre-built speakers reviewed in our last issue. At a price-point of $439, these speakers implied a quality that should be far in excess of the soundbar offerings currently dominating the market. It has been some time since anyone at DIYODE built a speaker, so we decided to review the build of this kit as much as the finished product. There will be no scientific testing, no Thiele and Small parameters, just an assessment of how the every-day enthusiast is going to find them.

Features:

POWER HANDLING:

15-60WRMS

FREQUENCY RESPONSE:

60Hz- 20kHz

SENSITIVITY:

84dB

WOOFER:

4.5” with Proprietary cone material using natural fibres.

TWEETER:

19mm soft dome.

SIZE:

260 × 180 × 145mm, 3kg each.

UNBOXING

There was minimal packing material in the densely-packed box, with just one styrofoam sheet on top, with the resonance-damping material and tight fit of items providing the security. While great from an environmental standpoint, some slight damage to some MDF enclosure panel corners suggests that some extra packing material would not go astray. Besides that, all other components were secure, undamaged, and readily identifiable. Nothing is labelled, but as you’ll see, this is not necessary. No physical manual is present. Users can either use the PDF from the Loudspeaker Kit website on a device, or print it out themselves. The document is, however, very well illustrated, with clear photographs. The steps are generally easy to follow, although some careful thought will be needed to interpret a couple of steps. The manual even goes as far as suggesting the work surface be covered with baking paper instead of newspaper to avoid marking the cabinet when you apply your chosen finish.

Our Build

We won’t detail step-by-step how to build these speakers: That’s what the manual is for. Instead, we are describing any issues or ambiguities we found as we went along.

A layout and dry-fit of all components is advisable with any build, and tends to head off any potential problems. Missing parts are discovered, damage or poor fit is found, and challenging aspects of design can be identified. In this case, however, all parts went together quite well indeed. Even the design of the mitre joints for the cabinet parts ensured all lines were clean and met at almost seamless edges. This is difficult to achieve, even with modern CNC manufacturing, as many materials warp, shrink, or expand ever so slightly once they are cut.

The instructions call for several tools to be gathered, and the list seems to be complete.

The build starts by laying the cabinet back, base, top, and sides out on the table in the form of a net - the kind most of us remember from school when we learned about prisms. Masking tape is applied to the joins, then the assembly is inverted. Here, a discovery was made. The MDF parts are now hard to lift from the work surface, as there is no grip on the sloped edge and sliding tools under the edge will damage it. Instead, try placing masking tape tabs on the sides at step 1, which can be used once the assembly is inverted. These are used later anyway.

The manual details the gluing procedure very well. Follow it closely, as the glue in the joins is also the sealant - no separate sealant or caulking compound is applied in this kit. It is also the sole method of joining - no screws are used as on commercial units which are then covered in vinyl to hide them.

Once the cabinets are fully assembled, including the length of every single glued join being taped, the instructions detail how to use a ratchet strap to secure the whole assembly without damage. We happen to have a framing clamp in the DIYODE workshop, which is what you see in the images. The ratchet strap does the same job on such wide joins as these. Instead of the brick, we used a box of DIYODE magazines, of course! It was tempting to screw down the crossovers before gluing the cabinet, but the manual makes no mention of this. Don’t do it, as further on in the process, there is a good reason to have an empty cabinet.

After the glue has thoroughly dried, you can finish the outside of the cabinets. The MDF may have to be lightly sanded, which is why the crossover was not installed earlier: It will become dusty, attracting moisture later. The manual details a particular finish that has been found particularly suitable, and gives some notes on other finishes. Whatever you choose, complete this before proceeding. As this is an “out-of-the-box” review, we left ours raw.

Installing the crossovers involves installing screws at the back of the assembled cabinet. Two different screw lengths are provided, with the shorter ones being the size for the crossovers. The manual says five screws for each crossover, but only eight were in the bag. The crossover is manipulated into the cabinet through the cut-out for the woofer, and the screwdriver will have to be used through both here and the tweeter cut-out. It takes care to succeed, and the screws may not end up perpendicular. Additionally, even with the shorter screws, they just begin to leave raised impressions on the back panel, so only tighten them enough to hold the PCB in place.

Next, the manual calls out that the terminals on the crossover leads need to be opened out carefully with a screwdriver. What is not called out is that you can open them too much, which is not a major drama. If you slide any terminal onto its spade and find it too loose, you can squeeze gently with a pair of pliers to close it slightly.

When installing the external parts, the rear binding posts go on first, being careful to orient them so they are the correct way up when the speaker sits on the shelf or ground. The binding posts go at the bottom of the back panel when the cabinet is stood up. Installation of the tweeter comes next, and we had to take a little care to get the tweeter wires and terminals to go through the cut-out and stay in their slots. The woofer was easier, but the spade terminals on it are on a less forgiving mounting, so exercise caution when sliding the terminals on to avoid breakage. When you have connected each one, use the longer screws to secure each. Partly install all four screws to ensure alignment, then tighten them down little by little across each one. In other words, a few turns of one, then the next, in a circuit, until they are tight.

The last thing to install is the port. This is supposed to slide straight in, but was too big for its cut-out. On the first one, the plastic retaining ribs engaged too tightly and began to peel. As a consequence, the port does not sit quite flush on the surface. On the second cabinet, the ribs on the port were shaved down with a scalpel, which solved the problem.

The next challenge was attaching the grille cloth. This involves contact adhesive being applied to the back of the grille frame, which in turn, requires that this area be masked. The manual describes a template, which looks great, with tabs to stick it down and pull handles to remove it. However, it is nowhere to be seen in the manual or the downloads section of the web page for the product. We used masking tape instead. Spray adhesive works best, and needs to be applied by spraying at an angle away from the side so that only the back is covered.

After the manufacturer’s recommended drying time, lay the frame over the grille cloth. The technique takes some refining, but is essentially this: Start by folding cloth over the middle of one long side onto the glue. Hold with a finger, and with your free hand, stretch the cloth slightly to one side, then fold more cloth over. Continue to the end but stop short of the corners. Now stretch the other long side onto the frame. Wrinkles should be present if tension is correct. These are eliminated when you stretch the cloth into place at the ends. All that remains is the corners, which also involve careful stretching, detailed in the manual. We found a little extra adhesive was helpful here, between layers of cloth.

After the glue has taken and set, use a sharp blade to trim the cloth in the groove provided. We used a scalpel for this, and had some trouble with the corners where the cloth was thicker. However, once it was done, the grilles snapped neatly to their magnetic attachments under the surface of the MDF of the cabinet. They only go on one way, as there are tabs that will impact on the woofer if the orientation is wrong. The overall effect looks professional and neat, although our own workmanship has some room for practice, particularly around the corners. Now, all that remained was to test them out!

PERFORMANCE

The most obvious way to test these speakers is with the ADHA27BT hybrid amplifier from Loudspeaker Kit that we reviewed in Issue 27. The speakers were duly connected, and a device paired to the Bluetooth. Whilst playing the office Spotify playlist, the first thing that became obvious was that the bass had much more range and depth than other speakers we had tried around the office; even those from some expensive brands who charge $4000+ for a 7.1 channel package. Also of note was how crisp the higher frequencies were. Not noisy, harsh, and scratchy as some speakers can be, but smooth and comfortable. We used a variety of music, and some spoken word as well.

We did notice some perceived inadequacies in parts of the frequency response, and a sound that we thought was preamplifier chipping. However, this turned out to be a sampling rate issue with the source. We switched to a YouTube video streaming in 1440p, a music video which solved the flat spots in the sound we could hear. YouTube videos are streamed with audio tracks which increase in sample rate with the display resolution, so choosing a higher resolution will yield higher sound. Many people don’t notice the difference with regular PC speakers, headphones, or TV speakers. The most impressive sound was actually not music or voice, but the audio from a high-quality video of fighter aircraft flying the low-level mach loop in Wales. The sound of a jet-engined aircraft at power is hard to replicate, with both a high dynamic range, and a very rich set of frequencies in between. While no speaker can come close to the feeling of standing at a military air show, these speakers put in an applaudable effort and gave a sound that certainly did the video justice.

All up, we were impressed by the performance of the LSK-M4S kit. Whether or not they’re worth the $439 asking price depends on what you want to listen to, in what environment, and how good your hearing is in the first place. But for those who are already prepared to pay much more for pre-built high-quality speakers, the LSK M4S is a comfortable choice.

Shopping List:

Amplifier & Speaker available at The Loudspeaker Kit: http://www.theloudspeakerkit.com/