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AUDIO FORUMS >> D.I.Y. >> Carlson enclosure build
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Message started by Tooppy on 04/17/20 at 19:57:55

Title: Carlson enclosure build
Post by Tooppy on 04/17/20 at 19:57:55

Archie,

I have posted pictures of some Big OB and Medium size I made quickly to test .

Title: Re: Steve's BIG BETSY Project
Post by Archie on 04/18/20 at 00:35:24

Sorry, I'm not seeing them.

Title: Re: Steve's BIG BETSY Project
Post by JBzen on 04/18/20 at 07:28:14

Archie,

Page 25 and 26 of this thread contain Tooppy's pictures of the green board test baffles.

John

Title: Re: Steve's BIG BETSY Project
Post by Tooppy on 04/18/20 at 10:43:23

@Acousticzen

Here are some pictures. Consider it is far from being finished, I leave the top and back unsealed to make eventual modification.
Also, this type of material is the worse to work with and the planks you buy are not flat because of bad storage which raise a lot of sealing problems.
But it is cheap, avalaible, in fact it is virtually the only thing avalaible here and for that 2.2cm thickness I waited 2 months, and the main thing, the most important it is heterogeneous which is very important to avoiding internal standing waves.
I hate damping which muffle the sound, here there is none.
Living in a flat, all is made on my kitchen table on my best.

Title: Re: Steve's BIG BETSY Project
Post by Tooppy on 04/18/20 at 10:45:21

Well, only one picture appeared

Title: Re: Steve's BIG BETSY Project
Post by Tooppy on 04/18/20 at 10:46:57

It seems I have to do one picture at a time
Here is the inside from the top

Title: Re: Steve's BIG BETSY Project
Post by Archie on 04/18/20 at 17:40:36

Thanks for the picture link. I remember seeing them now. I'm not surprised that the foam boards didn't do much for the sound. These new enclosures look interesting. Hopefully, they'll do it for you. The F15 driver is really special.

Title: Re: Steve's BIG BETSY Project
Post by TomR on 04/28/20 at 18:39:29

Tooppy,
I am interested in your listening impressions of the Karlson enclosures compared to the open baffle.

Did you calculate a specific Karlson enclosure for the F15, or did you use a existing design ?

Please advise,
Tom in Lafayette

Title: Re: Steve's BIG BETSY Project
Post by Tooppy on 04/29/20 at 14:18:15

Tom,

I just upscaled for a 15' and don't believe very precise measurements are critical, they are not.
I tried different kind of bracing/internal partition, it make virtually no differences.
I even tried adding a tweeter, compression and cone, with a crossover 18db at 1800Hz, the thing works better alone.
As such it might be good to try a phase correction of some kind to see, it's all depend of your room.
Earlier I mentioned I listen at very low level, with an OB I lose a lot.
With this K I have back all the music, it fill up the room and it gives the feeling I play to loud but it is not the case, I hardly hear anything if I go to the next room.
Big box reproduces large sound and I love it. The Japaneses play big JBL in very small listening rooms, they are right.
OB's placement need big rooms as they must be at least 4 feet away from any wall, that is to say in a dedicated room. I am happy I tried to realize it.
Let me repeat that the material used is very important, if you use plain wood you may need damping and then you enter probably into very unpleasant experiences of trials/errors which might never be conclusive so deceptive on what a K could be.

Title: Re: Steve's BIG BETSY Project
Post by Tooppy on 04/30/20 at 18:50:06

Tom,

Actually I didn't answer correctly, I scaled up to get the approximate speaker volume the Lii F15 needs and the vent surface. All this based on the Lii's drawing.

Title: Re: Steve's BIG BETSY Project
Post by TomR on 05/01/20 at 15:38:19

Thank you for the clarification, from your last response I was still a unsure exactly how you determined size/volume.

Looking at your photos and comparing them to existing Karlson enclosure plans, your build looks more like a quarter wave horn? Other cabinet plans show a rectangular vent or slots for the driver back wave to exit, although Karlson enclosures seem to vary a bit ?

Tom in Lafayette

Title: Re: Steve's BIG BETSY Project
Post by Tooppy on 05/01/20 at 17:31:00

Tom,

You have different type of Karlson enclosures, you are referring to the K15 or K12 which is effectively rather different. Actually it would have been easier for me to do K15 as I made before a XK4, but I wanted to try the Karlsonator which you could call a resonator.
While I didn't built the K15 for this Lii F15, I am pretty sure it would work perfectly.

Title: Re: Steve's BIG BETSY Project
Post by TomR on 05/04/20 at 02:22:59

Thanks for the clarification - I have similar listing issues, where Karlsonator may be a better implementation choice. I will continue to research.....

Thanks,
Tom in Lafayette

Title: Re: Carlson enclosure build
Post by Tooppy on 05/20/20 at 10:08:27

Thanks Steve to have moved this to a new topic. My built is nearly finished, I will post extra pictures as soon as possible.

To me the subject was "what kind of speaker can we make using these Lii F15 as they should", meaning as full range.
You did it very elegantly with an OB and readers of this forum should look at it very carefully because it could well be THE solution for many, at least to the ones who listen to music and not to a system.
They are simple, very well built and beautiful, nothing on the signal path from a very low power amp like the ones you propose, there is a lot to like.

But in my room I cannot leave four feet behind the speakers, I need to be nearer the walls, so I tried a different approach I had for a long time in my mind and it works.....but it is a hell of a job to craft at least with my means. :P :P

Title: Re: Carlson enclosure build
Post by gnarlydad on 05/21/20 at 04:44:36

Toopy, from my somewhat limited experience as a DIY speaker builder, and some rather ancient history as a custom cabinet maker, I think you're doing a brilliant job. You're designing solutions that work in your space. Not an easy thing to do. Good job.

Title: Re: Carlson enclosure build
Post by Tooppy on 05/25/20 at 23:02:39

Hi

here is the (virtually) finished speaker

Title: Re: Carlson enclosure build
Post by DirtDawg on 03/29/22 at 16:20:04

Hi, Troopy,

Looks like your project is coming youir way. I intend to goof some with this Karlsonator idea, but mainly, you have made me want to gather up some of those F15 Lii drivvers.
[smiley=tunes50.gif]

Thuffering Th...

Title: Re: Carlson enclosure build
Post by DirtDawg on 03/29/22 at 16:29:46

Tom, you're right. Earlier Karlsons I remember seeing in my youth had an almost Aperiodic smallish, hampered port to the rear.

Title: Re: Carlson enclosure build
Post by 4krow on 04/28/22 at 03:35:47

I admire your bravery but dam your judgement. Pretty forward for me to say it like this, but by looking at your work, I see that you have talent in wood and other material work. Chip board and acrylic, unless both were much thicker, look like nothing but resonance in a horn design. I am not a big MDF fan either, but I know that its stiffness and density are easily superior to chip board. It would be wise to do some radical bracing and hope that it helps. BTW, I am impressed at the choice that you made for the design of the cabinet. Never heard one, but it is tempting for me to build some day.
I guess that the final test is listening and deciding or not from there.

Title: Re: Carlson enclosure build
Post by Tooppy on 06/10/22 at 17:32:18

Back to update this thread.
After long listening, I have taken off the plexi front wings, I gain spaciousness. I replaced it with normal thin jersey. The aesthetic isn't what I was after, now they look like big boxes. I can always take it off but I have two young grand sons who are very good at digging fingers and it prevent dust as well.
These Lii F15 are really good drivers, I am often impressed wondering how they could reproduce certains sounds together, a real joy!
I am waiting for my UFO to be built, may be in two months time now, then I'll be able to compare it with my FirstWatt F5, I expect a wider scenic image.