built byBjoern/Sweden

Hejsan Troels,
Har nu färdigställt mina Ekta och känner mig till sist mycket nöjd med slutresultatet, både gällande utseende och ljudkvalitet! Fick justera en del med mellanregistret innan det blev perfekt. Hade problem med resonanser främst gällande pianoanslag som visade sig bero på att jag inte hade fasat tillräckligt i baffelhålet direkt bakom 12M-elementet… Noterade tidigt att du påtalat om detta men förstod inte att det är så extremt känsligt. Mycket viktigt att göra detta med omsorg. Efter denna justering blev pianoljudet perfekt!
Har även laborerat med olika mängder av dämpmaterial (vi har två st egna får på tomten så får-ull blev det givna valet) resultatet blev relativt lite ull som ger ett mer distinkt/klarare mellanregister. Mycket imponerande djupbas, går lågt samt rent ljud.Stort tack för byggbeskrivningar samt för all hjälp! Finns det plats på din web-sida” för ytterligare Ekta-bilder?
Mvh Björn Jägerstedt

In English:
Have finally finished my Ektas and I'm very pleased with the result, both in terms of appearance and the quality of the sound. Had to adjust the mid a bit before it turned out right due to resonances apparent on piano recordings. This turned out to be related to not chamfering the mid driver hole properly. Very important to do this correctly. After this, piano sound was just perfect. I have also tried various amounts of damping material (I happen to have two sheep on the estate, so sheep's wool was the thing to use), and the result was a fairly small amount of wool for the mid chamber, providing a more focused and clear midrange. The bottom octave is very impressive; this speaker goes deep and it's clean. Thanks for the article and help during construction. Maybe you have room for more Ektas on your website? Best regards Björn Jägerstedt.

Thanks Björn for the kind words and lovely pics. I'm amazed by the quality of your cabinet work. A masterpiece it is!
I can't imagine the many hours that has gone into making these cabs.
I'm particularly pleased by your comments to the need for chamfering the driver holes, not least from a small driver like the 12M. Having a rather thick front panel, a small mid easily gets stuck in a deep hole, not having enough space for breathing. I know I'm reiterating this to the point where people get sick, but the energy from the rear of a driver is exactly the same as that released from the front, and it's of no use driver manufacturers do all they can to make driver chassis as ventilated as possible when all we do in return is suffocating their drivers by not ensuring proper ventilation at the rear. I'll make a small study of this some day and do try to see if cumulative spectral decay (CSD/waterfall plots) can reveal the problem.
Kind regards, Troels

Summary from my experiences building the “Ekta”,
(Inspiration from Sonus faber)

Take your time and make a detailed drawing, which will save you a lot of time in the end. After several hours behind the CAD, time to practices!!

All curved parts were made by hand, using a band sawing machine, and then adjusted to exact form with help of a vertically sand papering machine. (tallriksslip)

Side panels:3 x 9mm MDF = tot 27mm, all slots filled with sand putty. (sandspackel). Weight of each finished speaker: 34kg

"Cremona” chamfered front baffle, later on covered with ”leather”. And please have a look at the midrange opening, you need to work more with the inside chamfering then showed here!

Finally ready for veneering!! Used Plastic Padding as putty (Yes, it’s my old Honda CB-750 in the background..)

Maple veneer thickness 0,5mm from “Fanerkompaniet” Stockholm. Relative easy to bend over the front radius (R15mm)

I used contact adhesive, and placed the pieces of veneer roughly 1mm in between (later on you have to cut clean the slots). I can’t really recommend using this type of glue, it’s hard to get a perfect and strong adherence (later on I found some small “non glued” areas..).

Worked with 3 strips at the time (yes, it takes time..).

I made a simple fixture plate for pressing the veneer close to the radius. Later on cut cleaned the excesses material using the steel rule and sharp knife.

Crossover for mid/treble in bottom under the cabinet.

Cross-over for bass inside.

Some of my tools. No special tools or machines were used.

Width of slots: 1,8-2mm , after cutting both sides, clean with a sharp narrow tool, I used a fine screwdriver!

Yes, you need a lot of sharp blades. Change often!!!! Otherwise the veneer will split.

Ready for blacklines! 28 slots/cabinet x 2sides x 2cabinets Makes totally 112 cuts, puhh….Use a very bendable steel rule (I took an old saw-blade from my sliding saw) and be very steady at your hand. Again, Take your time!

Black lines made by a mix of Plastic Padding and carbon black (kimrök) Before the sandpaper -use a sharp blade to reduce/plane the overflow material. If you go direct with sandpaper there will be a lot of black powder filling up the structure of the veneer. I used a electric hand eccentric sandpaper machine with internal “vacuumcleaner ” (Bosch PEX400 or similar) Please be careful, thickness only 0,5mm..

Quite nice, or? Next moment, painting with mordant (bets).

After the mordant get dried, the surface become very dull and structure of the veneer got quite diffuse. To regenerate, polish with steel wool, and the structure will return again! Finally, I treated with 5 layers of shellac (steel wool after every layer). The surface becomes very glossy, but personally I prefer to have it a little duller so decided to polish with steel wool.

Damping:   Pure natural material from Nedre Lundby!!!

After washing with soap water, then ready to tear the wool.