That Old Kit Bag

Medallion cabinet kit for Lowther loudspeakers: $1100 plus shipping. Manufactured and distributed by Lowther America, PO Box 4758, Salem, OR 97302. (503)370-9115. www.lowther-america.com

This one isn't for lawyers. Nor is it for doctors, dentists, lobbyists, CEOs, marketing consultants, therapists, elementary school psychologists, or, ironically, owners of high end audio "salons." Basically, if your time is worth $100 an hour or more, then building your own Medallion cabinets is a waste.

On the other hand:

If you've noticed that your car runs better after you change the oil yourself rather than letting the local Kwiky Loob do it (should I have added "car psychologist" to the list?), maybe you should try this kit anyway. Seven out of the nine professionals listed above could probably do the work as well as anyone, assuming they're also blessed with patience and the ability to follow simple written instructions.

Talents required? The biggest positive impact you can have on any home woodworking project is in spending lots of time sanding and smoothing its surfaces--which requires virtually no training and is, up to a point (read on), a "more is more" kind of thing. If you can move your hand steadily back and forth for more than a minute or two, a skill which I suspect many audiophiles possess, you've got it beat.

Tools required? Here things are a bit more specialized than the above, although not so fiddly as genetic engineering or for that matter serious woodworking from scratch. But you'll need to invest in the following if you don't have them already:

* A hand-held electric sander, plus lots and lots of sandpaper of various grades. You will need this not only for the smoothing of the wood in preparation for finishing, but also to help take a bit of the edge off certain parts which otherwise won't fit into their respective "dadoes" (the slots routed for them in their adjoining parts).

* Some glue. Most likely you'll buy something called aliphatic resin glue, which is what's in those bottles labeled "Titebond," "Elmer's Carpenter Glue," "Weldwood," etc. This is plain ol' yellow wood glue, and it's perfect for a project like this.

Alternatives include hide glue (as in "hide the pets"--haw haw haw), construction glues such as "Liquid Nails," and various modern polyurethane glues and epoxies. Some or all of these may have an edge in terms of bond strength, gap-filling qualities, "tack" during initial assembly, or whatever, but for a project like this, I doubt whether those gains are worth their extra toxicity (polyurethanes and epoxies are very bad for your skin), cost, or pain-in-the-ass factor. That goes for hide glue in particular, which must be dissolved in hot water and kept warm in, of all things, a glue pot.

Titebond gets my vote. One quart (about 5 bucks) wasn't quite enough for me, but then some of that may have been wasted during the correction of certain boneheaded mistakes.

* Some wood-filling putty. You'll need this in order to make the inside horn seams less abruptly angular and more rounded--to smooth out the transitions from one board to another. Filler will also come in handy for certain cosmetic tasks, such as smoothing out irregularities in panel-to panel seams.

There are lots of different putties on your dealer's shelf, and I haven't tried most of them. The Medallion manual recommends something called Wonderfill, which isn't stocked at any stores near me. So I bought Elmer's, and it seems okay. An 8-ounce container is more than enough for both speakers.

* A mallet--because some of these parts have to be banged together with real enthusiasm. A hammer won't do, because its force is concentrated over too small an area, and that will damage the wood. What you need to buy is a big rubber-headed mallet, the kind preferred by generations of cartoon mice.

* At least two bar clamps (but preferably three, four, or even more). These come in various sizes and types; you need to make sure that your clamps can accommodate a 24-inch-wide object, and that there are rubber or leather pads on the contact surfaces to protect the wood (although rubber pads are available as separate items for most clamps, too). Expect to spend between $12 and $20 apiece for these. Hint No.1: Three or four cheap bar clamps will get you farther with this kit than two expensive ones.

* Two band clamps. A band clamp is a half-inch wide strap made out of nylon webbing, long enough to fit around almost any woodworking project and looped through a ratchet or turnbuckle kind of thing. The idea is to loop the strap around your cabinet or whatever, and then tighten the ratchet to hold the parts tightly together. Simple.

I had some trouble getting hold of band clamps for my Medallion kit. Two building supply stores in town didn't have the slightest frigging idea what I was talking about when I described them, and there isn't even such a thing in the Woodworker's Supply catalog, believe it or not. I finally found a couple of band clamps in a hardware store, and paid about $14 apiece for them.

* Miscellaneous items in the "helpful but not essential" category include a T-square, ruler, and straightedge, plus a few small C-clamps, lots of rags for mopping up accidents (or even glue spillage), some of those 3M "sanding sponge" things for smoothing out curves inside the horn, and a flashlight (useful for peering inside the cabinet to make sure the panels are seated properly). By the way, a drill is necessary for making holes through the baffles for the speaker wire, the bit size depending on what hookup wire you use. And for safety's sake, a pair of goggles and a few disposable sanding masks should in fact be considered essential.

Now: When you order this kit from the folks at Lowther America, the parts for both cabinets are shipped to you in one big, single, big crate. Did I mention its size? It's big. You look at it and you think: tree. Or maybe you think: high-end audio salon owner.

What it is is heavy, because it's a bunch of big boards packed really tight into a box made of even bigger boards. Boards are heavy, Bubba, especially this many of 'em. The kit has to travel via common carrier (UPS doesn't mess with anything this heavy), and there's a fifty-fifty chance the driver who delivers it will pretend that it's your job to get it off his truck. Hint No.2: He's pulling your leg. (Truckers love practical jokes, especially ones where an exploding testicle is the punch line.) It's the carrier's responsibility to get the thing to the front door of your house or apartment building, and if the shipping company was too cheap or stoopid to send a truck with a hydraulic lift, that's their problem.

If you were upset that Lowther America didn't make life easier by putting the two kits into two separate (lighter) boxes, you'll lighten up when you figure out what that big crate is for: Mister audiophile, here's your new workbench! The shipping crate, once emptied of all the parts and flipped onto its front, is a perfect work surface: The cabinet parts rest nicely across the built-in skids, and that makes it easy to get all sorts of clamps underneath the bottom-most panel. And when your speakers are done, you can probably make the crate into something else. (What if the Reagan/Thatcher team gets back into office in the year 2000? Mister middle-class audiophile, here's your new house!)

The instruction manual is good in a minimalist way. Writer Dan "Dr. Bottlehead" Schmalle of Electronic Tonalities fame (check out the always recommendable e-zine Valve at www.bottlehead.com) was actually the first person to build a pair of these as a kit, working with pre-made parts but no written guide--just the blueprints and some rough assembly drawings. It was his job to put himself in the place of the inexperienced builder (not hard) and to come up with some helpful written instructions. He's done that nicely.

My only quibbles are minor, and all have to do with the recommended order of some steps. For instance, the instructions recommend that, just before gluing the last major panel in place and thus sealing the box, you should get out the putty and smooth out the transitions between the boards that comprise the horn. My very strong advice is to not wait that long: Do the joint-smoothing (!) right after the four basic parts of the inner horn (nos. 7, 8, 9, and 10) are in place and their glue has dried. Putting it off makes the task a lot harder, because the space gets tight and sanding in particular becomes tricky.

My recommendation goes a step further: Do the putty-and-sanding thing on all the transitions as you make them, and not just the ones mentioned above. Then, before everything is sealed up, use whatever product you have selected as a final finish to coat the interior horn surfaces. For this, two coats should suffice: The first one acts as a primer/sealer and raises the grain of the wood; sand lightly with 150 grit once it's dry, and then brush on a second coat. (Don't forget to do the same to the appropriate inner surfaces of the top panel and the side panel that has yet to be installed--but at the same time, mask off those areas which will be glued or which, after final assembly, will show--since you're going to have to stain or paint those, and finishing them now will screw up everything.)

The point of all that is to make the inside of the folded horn nice and smooth, which horn specialists have long suggested is necessary for good performance. Cabinet maker and horn designer Dave Clark of DC Audio advises caution, though: You want smooth, he says, but not hard or glassy--which will make the sound hard and glassy. A two-coat limit is good for any brushable finish (up to that point you're still pretty much just sealing the wood), but Clark suggests trying wax as a finishing alternative for the inside of the horn.

How well do these cabinets go together? As with just about everything else--whether an amplifier kit or a toddler swing marked "some assembly required"--most of it is fun, but some of it will make you curse like a sailor with a nerve condition. Each speaker contains almost 30 parts, not counting nuts, bolts, and drivers, and the vast majority of those parts are beautifully made and fit together neatly.

But a few don't. Parts 13 and 14, which are two of the corner braces inside the horn, were too big and too small, respectively. On both of the speakers I built, the former needed to be sanded down and the latter needed to be shimmed in order to properly span the surfaces they are supposed to brace. Part 5, the exterior back panel, is too small in both width and height. And, finally, part 18--a horizontal board which defines the bottom of the horn mouth--is either slightly warped or else the dadoes cut for it in the side panels are way too narrow. Whatever the cause, part 18 needed lots of sanding before it would fit--again, on both speakers.

Incidentally, that mis-sizing of the exterior back panel caused some assembly confusion. As intended, the rabbeted edges of both the top and bottom panels go toward the back of the cabinet. But since the back panels supplied for both of my kit cabinets didn't fit, regardless of which way the top and bottom were installed, the orientation of the latter two parts wasn't at all clear--and the instructions don't offer a clue. That's a problem Schmalle could not have forseen: On the pre-built Medallion samples, the back panels are the right size, so the ones on Schmalle's test pair probably were, too.

In any event, Lowther America assures me that these few inaccuracies are being corrected. In fact, in the time since my own sample kit was shipped, the company that manufactures the kit pieces upgraded their factory with CNC routing and machining tools--so it's reasonable to expect that all the parts in all future shipments will be as close to perfect as possible.

From a design point of view, the Medallion mixes mostly very good ideas with only a couple of not-so-good ones. What's good is the overall way in which the speaker's designers have taken a proven horn design--Lowther's original Acousta--and transposed it to a less bulky, more domestically friendly package.

What's more, in doing so, they've given us a cabinet with a much narrower front baffle than is usually found in these types of enclosures. All other things being equal, that's good, sonically and aesthetically. The Medallion's designers have also eliminated the Acousta's notorious "magnet box," thus removing its pontential for interfering with the back wave.

And those are just the theoretical plusses. The real-world plusses speak for themselves, inasmuch as a Medallion cabinet driven with a Lowther PM2A or PM5A loudspeaker plays music so convincingly well.

In the "plusses" column, let's also park the high quality of the wood itself. Most of the parts are plywood, but a very high grade of plywood, with usable, decent-looking veneer on at least one surface. A very heavy Medite-plywood laminate is used where air pressure is at its most critical, and certain other parts are solid wood. There's not a scrap of crap in sight. But keep in mind: Even with high quality plywood such as this, a veneer is never more than skin deep--so don't depend on sanding to make poorly aligned parts flush with one another (don't ask how I know). Take care to fit things together perfectly the first time, so your finish sanding can be kept to a minimum.

The less successful aspects of the Medallion design all relate to the same thing: The uppermost boundary of this design's folded horn is defined by its (exterior) top plate, which is itself the very last part to be added in constructing the cabinet. This poses a problem: The builder has no way to make sure that the other parts of the interior horn are properly contacting the inside of that top plate when the latter is glued in place.

The pebble in my other shoe is this: Meaning no offense to its manufacturers, if you build the Medallion cabinet kit, you had damn well better like the Jena Labs cable that's supplied with it, because you're stuck with it for the rest of your life. Depending on the precise way in which you route it, the cable will have to travel through holes drilled in three or four different parts--at least one of which is completely and permamnently inaccessible once cabinet assembly is completed. Since the cable has to travel through the horn itself--and since any holes you make in those surfaces will have to be sealed very tightly around the cable once it's threaded through--you won't be able to change cables later on without severely compromising the operation of the horn.

Both the problems I've described could be solved with a simple redesign in which an INTERIOR plate seals off the folded horn and serves as its upper boundary. Such a part could be dadoed into the two side panels (which would also make it more rigid than the present arrangement) leaving a gap of, say, an inch or two left between it and the real (exterior) top plate. A big additional benefit is that the kit builder can now putty all of the panel-to-panel transitions within the horn, even the top ones.

The reason for leaving a gap between the inner and outer top plates? Run the cable through there. Now the horn is completely undisturbed; fewer holes need to be drilled for the cable; and all of the holes which do need to be drilled will remain reasonably easy to get at from outside the cabinet--meaning that, with a little work, the Medallion owner could change cables in that convergence-happy future of ours if he or she wishes to.

I don't know how long it took me to build these things (Jannie probably does), so let's just say a long time--surely longer than anyone thought I would take. I suppose I spent fourteen or fifteen hours a week over the course of three or four weeks. But if you can devote all your waking hours to this project (call in sick, unless you work for me), the estimated completion time would probably go way down; part of my trouble was in having to keep coming back to the project for an evening hour here, a Sunday morning there--and so I was forever getting back up to speed, figuring out what to do next.

But hallelujah: I got the job done. And I dragged the finished Medallions--my finished Medallions--upstairs for a tryout.

The results? Mine are at least as good as the prebuilt ones. At least. (Yes, and my car really does go faster after I wax it.)

But I wanted more. Ever the greedy hi-fi buff.

Here's where a little judicious tweaking comes in, courtesy of Lowther owner Jon Ver Halen. In order to fine-tune the size of the Medallion's compression chamber* and (hopefully) tame the driver's slight upper midrange weirdness, Jon recommends adding a product called Deflex to the inside of the cabinet. This is a rubbery acoustical panel, flat on one side and deeply ribbed (here we go again) on the other. Its manufacturer, Spectra Dynamics,** doesn't publish much in the way of specifications, but it appears as though the stuff deals with unwanted sound waves within an enclosure by sapping their energy through deflection, rather than merely trying to absorb them--although, obviously, the product will not be effective below a certain frequency.

Jon and others consider Deflex Wrap (this is the stuff with the straight, parallel ribs and not the concentric circles) useful in a rear-loaded horn's compression chamber, to help keep reflected waves from interfering with the back of the cone. But at least as important is the idea of using this chunky material to reduce the effective volume of the enclosure behind the driver.

Why adjust the size of the compression chamber? That's a complex subject (and not one which I pretend to understand beyond a superficial level). Once the throat area, length, flare rate, and mouth area of a horn have been selected (all interrelated and determined in part by the desired low-frequency cutoff point and other factors), the compression chamber volume can be fine-tuned for the driver being used. Its precise dimensions are affected by non-obvious things like diaphragm mass and voice coil length.

Yet another of these factors is the flux density in the driver's voice gap, something which should make any Lowther enthusiast prick up his ears. High flux density is one of this brand's house specialties, of course--yet even so, the various Lowther models differ quite a lot. The PM6A, for which the Medallion was designed, exhibits a flux density of 1.75 Teslas. That's high. But the PM2A is almost 25 percent higher at 2.1 Tesla. There's no way that a compression chamber optimized for one will work with the other--and it so happens that the PM2A owner wants to make his or her enclosure volume smaller. Mr. Roy Hopps of the Lowther factory, confirms this for me, saying that there should be as much as a full liter's difference in volume between the compression chamber for a PM6A and that of a PM2A.

Enough techno-fiddly stuff for one day. I wound up adding almost a full 8.5 by 11-inch sheet to each compression chamber, and the thing is, it works. It works big-time, in fact. Would you believe floor-shaking bass from a Lowther? Neither would I--but on the song "White Man's Melody" from the otherwise dodgy Largo collection, that's precisely what I experienced on a couple of notes. Sure, that's the exception and not the rule, but my Medallions are now almost flat to 50 Hz, and I have unambiguously usable response well into the 40s--a very big improvement over stock. The Medallions are still a little light in the pants--but once you've heard how involving the Lowther drivers are, you forget to remember how low they can go.

So here I am, only three or four days past finishing the project. And the final analysis has nothing to do with bass depth or putty in the seams or any other such secondary things. The real test is this: I've been enjoying music late at night, after the baby goes to sleep. I've been listening early in the morning, before I leave the house. And more than just digging out old records to see how they sound, I've found myself digging out new ones to hear what the musical kicks they might contain.

I had fun building the Medallion kit--but I'm having even more fun now. That's the best and truest praise I can think of for something like this. If you want to know what the Lowther fuss is all about, this is an excellent way to get started.

*This term derives from the more traditional horn practice in which the rear wave of a driver is not used at all; rather, that half is enclosed or compressed in order to equalize the pressure on both sides of the diaphragm. (If a diaphragm tries to drive a column of air in a horn on one side, but is left to drive nothing but free air on the other side, its response will be decidedly non-linear.) The game changes in a rear-loaded horn such as this--where both front and rear waves contribute to the loudspeaker output--but the term compression chamber has stuck nonetheless.

**Deflex Wrap is available from The Parts Connection (800/769-0747) and Michael Percy Audio (415/669-7181). Incidentally, this is just one more product we like that is manufactured in England; conspiracy theorists--attend! End of footnote the second! Convergence!