Mini Karlsonator (0.53X) with Dual TC9FDs

Well, HUSTON, WE HAVE A PROBLEM!! I managed to get four of Faitalpro 4FE35-16 planning to go in 0.53X box but they are to large. As these drivers are 10cm in diameter they can't be mounted on driver board as the driver board is only 196mm in length. What to do? Is there Karlsonator box a little bit larger? Or to slide drivers on driver board one to left, other to right? There are plans for Karlsonator "8" but these are to big for my need, any suggestions????
Thanks in advance!
 
That's a good price! Since they are 16 Ohm, they should work well in parallel in Karlsonators. My very non-technical guess would be to scale it up proportionally to the driver size ratio, i.e. 33% bigger. But I'd like to see what X suggests.

I love the 0.53X set with dual 3FE25-16's that I built in 2017. They punch much higher than their size suggests. The initial harshness has also gone away and I don't use baffles steps anymore (hated them, to be honest).
 
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Well, HUSTON, WE HAVE A PROBLEM!! I managed to get four of Faitalpro 4FE35-16 planning to go in 0.53X box but they are to large. As these drivers are 10cm in diameter they can't be mounted on driver board as the driver board is only 196mm in length. What to do? Is there Karlsonator box a little bit larger? Or to slide drivers on driver board one to left, other to right? There are plans for Karlsonator "8" but these are to big for my need, any suggestions????
Thanks in advance!
According to xrk971, the 16 ohm version of 4FE35 doesn't work well in this design because its Qts is too high. He modelled it for the 8 ohm version here:

https://www.diyaudio.com/community/...with-dual-tc9fds.239338/page-115#post-5249681

Impressive bass extension with the 8 ohm drivers:

F3 is about 45Hz
 
This seems to be a cross between a tapped horn and a MLTL with a diffraction slot on the front. I have seen xrk971's description of his Akabak simulation here:
https://www.diyaudio.com/community/...r-0-53x-with-dual-tc9fds.239338/#post-3564756

However this doesn't seem to include the short stuffed line above the driver, or the driver feeding into the front chamber.

Has anyone else had a go at simulating it? It's been a while since I played with Akabak but I am thinking of building a twin 4FE35 Karlsonator as it seems quite compact for the response.
 
perhaps you could come close in the LF with hornresp and the way TB46 modeled a "Karlflex"
 

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Thanks to GregB, xrk971, and jhofland for the opportunity to build a great pair of speakers. These mini-Ks with Faital Pro 3FE25-16s are an easy load for my 2A3 SE amps, and their sensitivity allows 3.5 watts per channel to drive them plenty loud enough for me. No BSC needed to get nice bass. Damping is mostly as suggested by xrk971, but I used thin melamine pad (a few mm thick) on the back of the front panel and about 75-80 percent of the interior surface, all attached using Titebond melamine glue for wood. I also used 1/4-inch by 1/16-inch foam weather stripping to seal the driver baffle as well as the back. I only put about 25 gm of polyfill above the speakers, completely teased out before placement. I've listened to YoYo Ma, Queen, Tony Rice, Miles Davis, and Ella Fitzgerald. So far everything sounds wonderful.
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Thanks. I can solder wire to tabs and goober finish on wood, but the real skill was in the original design, your modeling and scaling, and jhofland's construction. The boxes were a steal at the price. I think a search for magic eraser sheets on Amazon will bring up the thin melamine I used to line these.
 
Hello friends and thanks for a wonderful thread!

I made a thing for the 2x 4fe35-8, can someone confirm if this is a good or a bad thing?
I followed a suggestion to make a downsize from the original by 0,60x on height and depth and 0,47x in width, well kinda close ishhh anyhow!
But is it close enough?
It's done with 12mm plywood in mind.

Peace!
 

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The narrow part of the Karlson aperture acts as a single diffraction slot so it's width should be less than or equal the shortest wavelength desired, I take it? So for 20 kHz it should be around 15 mm wide. Is it worth changing the curvature to make the slot longer while maintaining the same total area of the port?
 
Anyone else built these with double 4FE35-8? I built a prototype with foamboard. Slightly disappointed compared with the double PA130-8 XKi's I built a few years back. Roll off quite sharply below 70 Hz and sound a little harsh. Probably over stuffed, too. I'll see if they break in and play around with the stuffing. The XKi's had chest thumping base down to the 40s.
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No, I have not built with 4FE35’s. I have only used 3FE25 and 3FE22. Sorry that the bass is not as good as PA130 but a 5.25in driver will usually have better bass than a 4in driver. Your construction looks good.

70Hz sounds about right for a 4in driver though. Maybe 60Hz if you make the final vent either longer or smaller (the narrow channel section at the top). This will come at expense of lower SPL. So maybe add 0.5mH and 4.7ohm (5W) resistor as baffle step compensation. This might balance sound and make it more pleasing overall.
 
I tried reducing the vent height from 25 to 15 mm but it didn't extend the bass noticeably and reduced the volume significantly. I reduced the polyfill stuffing density in the tapered section to 0.7 lbs/cu ft. I calculate the volume at 2.35L or 0.083 cu ft, giving a mass of 25g or 1 oz of polyfill. I added melamine foam to both sides of the front chamber and this has taken away the hollow sound. I tried with a narrower aperture at the top (12 mm) but more punch with 15mm. Sounding a lot better.