Spiral horn speakers under construction. Part3


Hey there,
Long time no post. Been kinda busy these days but I’m fortunately back in the business.

Finally got the cornu’s sanded, puttied, and white lacquered. It’s been quite a pain in the a** but they turned out great!
Getting the baltic birch plywood prepared for lacquering is a tough job. Lacquer reveals each and every small imperfection in the wood, so to get professional results close care had to be taken when sanding and polishing, specially on corners and joints.

DSC05561 DSC05560

MDF takes lacquer better, and would’ve been a good option if you’re sure you wanna give the speakers a lacquer finish but don’t wanna spend so much time preparing the wood. At the same time, however, you’ll lose the advantage of good baltic plywood acoustical characteristics and strength.

Besides painting the speakers, I also damped the driver’s cavity with some sheep’s wool, and hanged them towards the wall.
Tried different positions for the speakers, and finally placed them about 60cm high from the floor and 60 cm from a room’s corner. That seems to improve the bass response at some extent.


To make a long story short, I’d say these speakers sound truly great. Bass doesn’t blow you away but there’re still loads of it in there, more than expected considering the small driver.  They’re really versatile, and perform pretty well in most situations and genres.  One thing to bare in mind is that they don’t seem to be intended for extremely low volumes, there must be some amount of air moving inside the horns to perform well. Normal listening home volumes, however, are more than enough to drive the speakers hard enough to sound good.


~ by fperezroig (22nanofarads.com) on October 16, 2013.

4 Responses to “Spiral horn speakers under construction. Part3”

  1. They look amazing, bet they sound great!

  2. Thanks Martin,
    It was a tough job but I’m really happy with the result!

  3. Congratulations, these look great! What amp are you using with them? I have some fe108es in BIB cabinets and they have plenty of bass. How do these compare to the little Karlsonators you have since built?

  4. Thank you Larry! I usually power them with a Single Ended EL84 Stereo amp I built sometime ago, and pair them with a tapped horn subwoofer. These are better overall speakers than the mini Karlsonators, imo. I’d say they offer a flatter frequency response, the sound is more open, balanced and clear. The karlsonators on the other hand provide a more pronounced low end, so they’re great as portable speakers to use without a sub. However, they can sometimes sound a bit nasal and constrained. They sound better placed on the floor, in my opinion. That said, all this is pretty subjective, and I did not make any frequency response measurements … Anyway, I’d bet anyone would prefer the cornus to the karlsonators, the latter being a great bang for the buck, though.

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