Mini Karlsonator (0.53X) with Dual TC9FDs

I think Beta10cx would be happy in a Karlsonator somewhat smaller than GregB's Karlsonator 12 and with somewhat higher tuning. The stock Karlsonator12 is tuned to 37Hz. Also, it might be good to look at Michael Chua's "Osprey" crossover for ideas as he's done extensive work with that coax to get good vocal reproduction. (I thought Eminence's suggested network was too muddy & "bland"

Osprey II - Eminence Beta 10CX 10" Coaxial - AmpsLab

Thanks for the link Freddi. Do you think the Betta 12CX would be better(please excuse unintentional pun). What did GregB use in the Karlsonator 12?
 
Finally got around to cutting all the foam core pieces for the 0.53x dual FE mini k’s. Need more time to glue them all up now!
 

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Finally got around to cutting all the foam core pieces for the 0.53x dual FE mini k’s. Need more time to glue them all up now!

Looking good!

Those 3FE25's are heavy. You may want to at least double-up the driver board. I used LitePly + additional stiffeners at the back.

My build is described here.

 

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Thanks Skylar! Your build was one that convinced me to give the dual 3FE25's a try. Yes, I plan to double up the driver board with another layer of foamcore and add some 1/4" plywood pieces for the driver screws to bite into, or just use a layer of the 1/4" ply instead of another layer of foamcore. What are your thoughts on the max thickness of the driver board before it begins to affect the air movement on the backside of the drivers? Was that another reason you went with a single layer of 3mm liteply?

Amplifier wise, are you still powering yours with ACA(s)? Any plans for different amps or pre-amps in the future? I'm looking forward to trying the 3FE25 mini-k's with the ALPHA 20 and AKSA Lender Preamp I built recently. I also have an ACA kit from the latest release and parts for the M2x, MoFo, and if I ever get the parts together I have boards for an EL34 Baby Huey tube amp. Really looking forward to trying all these combinations out with these speakers to see what I like best. I think this will keep me busy for a few years. ;)
 
What are your thoughts on the max thickness of the driver board before it begins to affect the air movement on the backside of the drivers? Was that another reason you went with a single layer of 3mm liteply?

I've read that two layers foam is not too thick. My reasoning for using just LitePly was that I had it on hand and reckoned that it would be sufficient.

Amplifier wise, are you still powering yours with ACA(s)?
Yes, I'm still using the ACA's at 6W - that's with the R15 mod. Haven't done the last mod that will take it to 8W yet, and the volume is fine for most music except some quiet classical. That is with just a B1 buffer - no gain.

Any plans for different amps or pre-amps in the future?
I'll probably build the AKSA Lender pre, since I have all the components and PCB's. That should be more than enough boost for the ACA on the quieter pieces.

For a totally different system, I'm planning to build the M2 and 2 Pi Tower speakers. This hobby is so addictive. I thought that the B1, ACA and Karls would be the end, but it turned out otherwise because I enjoy it - not because I'm not happy with my current system.
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The more I think about it, I'm probably going to go with the layer of 1/4" ply under the foamcore. I don't want to go much beyond that thickness wise.

Addictive is right! I'm slowly building a system for each room of the house now. Or at least, that's my excuse. :D And I figure since my family listens to a lot of music already, why shouldn't it sound its best! I just can't wait for the kids to grow up and want their own systems too.

Yes! Build the AKSA Lender pre! You won't be disappointed. I've read that the ACA sounds more authoritative with a good preamp behind it. I also built a WHAMMY HPA that i'm looking forward to trying with my ACA as a preamp. We'll see who wins!
 
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Corrugated Cardboard 0.4x Scale Karlsonator with single Vifa

Here is a cardboard build of the mini Karlsonator that ive recently made, i love the art deco/art nevou styling of Karlson enclosures and tried to incorporate some woodworking techniques to give it an Frank Lloyd Wright look. I recycled double layer corrugated cardboard that was a 1/4" thick so adjusted the overall size by a just a fraction to maintain the internal dimensions, doubled up the speaker baffle and used a router to put a fillet where the speaker protrudes form the back of the baffle. Im a wood worker by trade so i used a table saw and router to make everything square and flush, i also love math so mitered all the internal pieces lol. I also veneered the aperture wings with strips of walnut for appeal and rigidity, i also added a piece of redheart Padauk thats the width of the slot for the wings. There are still a few tweaks i plan to do, like felt and braces behind the wings of the aperture, but currently enjoying them as they are!

It blows my mind how this speaker sounds, the box design/alignment/aperture/material combination defies convention in every way. To me they sound very lush, for there size they cast a huge sound stage, the last photo that i posted shows there placement in my set up, underneath rather large hanging open baffles, and i often switch back and forth between the two sets, and sometimes forget that i have it set to the channel that karsonators are on and have assumed several times that i was listening to the open baffles, which have a massive sound stage. And of the two I find that i cant stop listening to the karsonators! With these i run a sub half the time depending on the genre and my mood, i often listen to them by themselves because they just sound so good.

The TC9FD18 is a special in and of itself, it is ultimately what led me to this particular thread, but in this box it really is magic. The glue is drying on a 3/4"ply/solid wood version of these that ive finished today, i will soon post pics and description on how it compares sonically to the cardboard version. Hopefully followed by some measurements of both.

Thank you xrk971 for sharing your knowledge and inspiring others with your works.
 

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I've drawn my own plans for the 0.53 Karlsonator with dual 3FE25-16's for A1 size 5mm foam core board.

See PDF files below.

NB: the baffles are 202mm wide (internal width of the speaker cabinet).

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