Super SEAS-Scanspeak 2-ways

[Elbert]

Over time, I've been in and out here seeking advice and contemplating all sorts of drivers and solutions for my ongoing project..

It really started as a plan to build some boxes for a couple of Access 6A drivers out of some leftover MDF..

But you know how it is when the snowball starts rolling..

Anyway, just thought I'd do a small write-up on the project so far, hopefully providing some inspiration and ideas to anyone reading..

Design criteria:

A pair of easy-to-place stereo-speakers ultimately to be used with a stereo-sub setup.

The set up will eventually be fully active with 3x90W mosfet amplifier stages (Elektor's Crescendo Millennium design) per channel, Using linkwitz active filter boards for X-over and response shaping.

As I mentioned, the project started with what was supposed to be a pair fo simple MDF boxes. Since I didn't prioritize LF extension and wanted something simple to work with/ tune, closed boxes were the order of the day.

The MDF I had was 19mm and the internal box volume ended up around 12 L.

Attached images show the box glued together except for the back.

Inside the box, I added some bracing, and as you can see, the bracing elements were cut and assembled at an angle to (hopefully) reduce standing waves.

Further to this, the inside was covered with sheets of bitumen and a soft squashy foam material normally used to insulate HVAC and plumbing equipment. iI is very dead, and in feel and appearance it is not entirely dissimmilar to the stuff they make earplugs out of. The stuff is called Armaflex if you wan to look it up on the web.

even without wadding, the boxes were very dead with only the bitumen and armaflex in place.

After adding bitumen and armaflex to the rear panels, they were simply glued in place.

But what about the finishing??

[Elbert]

After quite a bit of filling and sanding, I actually ended up with a pair of boxes that were quite heavy and solid, not to mention acoustically dead, in other words a good starting point for something that could evolve in to a more serious project than I had originally envisaged.

I realized that if I ended up with a nice sounding design, a degree of aesthetic appeal could complement the project nicely.

I like wood finish, but at the same time, I wanted to give the design some visual interest beyond an all veneer finish.

I decided to go for a plain black backside, so the first thing I did was to paint the rear black. This so I wouldn't mess up any subsequent veneering job with paint splatter and sanding dust.

For the front, I decided to go for a black "extra" baffle to be offset from the box by some 3mm rubber sheet, sort of a MDF-rubber-MDF sandwich baffle if you like.

You can see these extra baffles in the background..

[Elbert]

Now for the veneer...

What to choose?

I tend to like the darker types of wood, but this time I didn't want something too dark either..

I got some cherry veneer which had a touch of flame in the cut and some bird-pickings and twig-marks. I think this adds some life to a finish, I didn't want a veneer finsih that was too "perfect" and wallpaper like.

Out comes the glue, Iron and hobby knife!

And some heavy transformers are also useful for keeping the veneer in place as the glue dries!

[Elbert]

Veneer successfully applied and sanded down, but it looked a bit neutral and "ikea" like.. What will some coats of Oil do??

[Elbert]

Since I like a warm golden glow in wood, I decided to use a hardwood/ exotic wood Oil in stead of some lighter and more neutral alternatives.

How would it work with the relatively light cherry-veneer??

Quite well it turned out, at least to my taste.

It was quite enjoyable to see how the veneer came to life as the oil was applied.

[Elbert]

In the next image, you can see how I glued a rubber-sheet to the front of the box. After the glue had dried, holes were cut, and the front baffle was glued in place.

As you can see, the rubber sheet is a bit smaller than the actual baffle dimensions. This leaves a gap between the box and the glued on baffle that serves well to hide any minor (inevitable) dimensional discrepancies that would otherwise be obvious in a face-to-face assembly.

[Elbert]

Terminals and wiring is also required...

In stead of opting for the easy way out with standard DIY plastic terminal wells, I did a job in aluminium with some gold plated terminals.

Unfortunately, the picture doesn't do the back-side finish full justice..

I applied quite a few coatings of black interior paint, progressively sanding it down untill the last coating was finished with 1000 grit paper. The appearance is more that of silk matt laquer than painted MDF.

[Glowbug]

Looking great

[Elbert]

Didn't get pictures of the final assembly steps, so enjoy in stead the view of the delicious glass-fiber cone SEAS Exel units I was lucky enough to get my hands on!

[Elbert]

And now for the finished result:

As you can see, I didn't stop with adding a front baffle. On the baffle I glued a square sheet of the same armaflex material I used to line the inside of the boxes.

Not only for visual distinction and "countersinking" of the drive units, but allso for absorbtion of early reflections from the baffle. Well.. the last point is of course more intentionally than factual, but at least it can't hurt.

The tweeter, by the way, is a peerles (scanspeak) 104, a very nice unit for the price.