How I built a set of book-shelf loudspeakers

Being tired of not causing my neighbours any significant grief, I decided to upgrade from earphones to actual speakers. I settled on a "kit" containing pre-cut bare wood and a set of units from the Danish manufacturer Dynadio. The process of putting the things together is still on-going, and was/is done in three major steps.

Putting the boxes together

Speaker units JPG 3.5K Speaker units from Dynadio, the famous treble unit D28AF and the bass-mid unit 17W-75XL. As is customary for Dynadio units, the cross-over is a simply first order affair, with impedance correction for the treble. I bought the kit at Haut-parleur systemes, 17th arr Paris.

Bare wood JPG 3K Bare wood for the boxes. The 14.5L enclosures are constructed from 18mm MDMF (Medium Density Fibre Board), the best material for low-cost speaker boxes. The only beef I have with the pre-cut materials is that they come together as a box which has a slight edge on the front (so that one can use a grille and still see some wood). This doesn't make acoustic sense, and I don't want to use a grille anyway, so this edge went (at a later stage).

Glueing boxes JPG 3K Glueing the boxes, using nails for guidance and clamps for actual force. Since the boards were pre-cut to an acceptable precision, there was no real problem putting the boxes together straight. Using a few hours a setting time for each side, I was able to do the assembly in one day.

Mounting units JPG 3K Mounting the units in the finished boxes. The edge on the front mentioned above is clearly visible.

Listening to result JPG 4K Sunday night Listening to the result. I had spent all sunday putting the things together, so I forgot about the 22:00 curfew on noise, and let rip for a few minutes...

So, how do they sound? Well, I like the mid/treble (great voice reproduction); the bass was a bit boomy with the original reflex ports (which were the wrong size, anyway). The bass was sort-of fixed by stuffing a pair of socks in each reflex opening. The perspective is not too great, but Hi-Fi experts are falling over themselves in their haste to recommend free-standing placement for good perspective (one look at the picture should adequately document that I do not have room for such luxury).

Veneering the boxes

After a few hundred sarcastic remarks from sundry visitors (well, all of them did make comments..), I was finally sufficiently motivated to start veneering the boxes. My Hi-Fi friends were terribly encouraging ("I think it's easy; put the boxes in the trunk, drive to the carpenter, pay to have them veneered", "Well, veneering is one of those things one either does very well, or..."), but I decided to press ahead anyway.

I went and bought some veneer (called "Koto" - whatever that is), and had a go at it.

Sanding boxes JPG 4K Sanding the boxes after having sawed off the hideous edges and filled the gaps. I used two-component filler (probably epoxy) which sets really fast (a few minutes). On the other hand, it doesn't shrink, and it sets completely (doesn't stay soft in the centre), so I got a relaxed relationship with this - after a few hairy moments.

Glueing veneer
JPG 4K Glueing veneer to the boxes. This is the only step of the process which I would do different the next time. We [1] used contact glue which sets sort of instant on contact (hence the name, duh..). The problem is, that I had only made the panels slightly over-size. So, if we aligned a panel wrong, we might miss the edge of the box, and have to rip the veneer off. In one case we had to make a new panel, and in another case (the last panel - a front), we only just managed to get the panel off without wrecking it. Since there is a perfectly good alternative to contact glue (the same veneer comes with thermo-glue pre-applied, so it's possible to affix the veneer using an iron), I can only recommend that one doesn't use contact glue.

Finished boxes JPG 3K Finished and lacquered boxes. After lacquering (during which I damaged more - 2 - of the fragile edges than I had during the actual veneering), I cut holes for units. One notices the mirror-imaged matched fronts. This came about because I had bought a wide roll (50cm) of veneer; this was actually two narrow, mirror-imaged, pieces glued together on the back. So, since the box was narrower than half the width of the roll of veneer, I was able to cut two mirror image panels. Very nice, even if I do say so myself...

Finished speakers JPG 3K Finsished speakers. One speaker with units and all. I really wanted brass bolts (with allen heads) for mounting the units, but haven't been able to locate any. Apart from that, the best result I could possibly expect!

Thank you notes

Thanks to Steven E. for materials and tools.
[1] Thanks also the Rosa G. for materials/tools, but above all for helping out with the actual veneering process, and getting the bright idea which saved the last panel from being a complete disaster. Absolutely couldn't have done it without you!

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Last modified: Mon Dec 15 10:35:59 CET 1997