Mini Karlsonator (0.53X) with Dual TC9FDs

[xrk971]

Those are based on Jhofland’s plans - it’s sketchup file.

 

[twocents]

I am midway through building these with the dual TC9FDs.

I have a pair of Alpha 15a in h-frame that I use for bass.

I bet this will be a killer combo! I'd love to hear your impressions.

 

[unaHm]

Finally! I have gotten far enough in my build to verify accuracy of my plans. I re-did the plans because I wanted to do the score and fold method and there were no plans for that. I made my model starting with the 0.4x Karlsonator scaling (detailed in the attached plans) and then I modeled the folded sections as sheet metal in SolidWorks. SolidWorks will "unfold" sheet metal parts, I just told it to apply zero stretching of the material on the outer radius of the bends. This way SolidWorks calculates the cut length and bend lines automatically. I have made the cuts and bends as shown in my plans and they work great.

I also included the aperture profile to scale so it can be used as a template. The aperture starts at a 3/16" width and the curve was calculated from the equation given by XRK (I can't find the post right now, but I think it's earlier in this thread).

As far as units go, I like to work with decimal inches but I know most people don't have decimal inch rulers (I have machinist rules I use). Most rulers/tape measures that are 30 inches long have 1/16 inch increments so I included dimensions on the cut diagrams to the nearest 1/32. That way people (in the USA at least) don't need special equipment or lots of work calculating to use these plans, you just need to be able to estimate half way between 1/16 inch marks. If there is a desire for a metric plan I can easily change the units (easy as making a selection from a drop down menu), so let me know.

I did not include my suggested brace from the modal analysis. I don't have a measurement microphone (yet) and I didn't want to show plans including something that's untested.

I tried to give all applicable credit on the first page. If there needs to be any corrections please let me know.

I hope others find these useful!

I was going to get started on cutting out these plans tonight, but I seem to have misplaced my straight edge in one move or another I was thinking about printing out the designs to scale, and then just following the lines, but at the moment I'm struggling to think of what factor I would need to scale the printout by in order to get it to the right size.

If anyone has any suggestions, please let me know!

Thanks,

Dan

 

[MuddJester]

The sheets with the cut plans are 1:4. I think this is the second time someone asked about scaling, I need to remember to include that next plans I make.
Good luck!

 

[unaHm]

The sheets with the cut plans are 1:4. I think this is the second time someone asked about scaling, I need to remember to include that next plans I make.
Good luck!

Thanks MuddJester! I should have checked the thread a little more thoroughly before asking, but I appreciate your response!

@xrk971: could you add a note to the first post in the thread about the scaling for this diagram? I'm just thinking of the next incarnation of me!

 

[xrk971]

@xrk971: could you add a note to the first post in the thread about the scaling for this diagram? I'm just thinking of the next incarnation of me!

Done.

 

[unaHm]

Done.

Thank-you sir! I've just finished cutting out the pieces based on Muddjester's template, so I'm now on my search for my hot glue gun

 

[unaHm]

Well, I started gluing the first one together, and got more depressed by my edge cutting as I went along. I could fix it, but I'd rather not have anything to fix!

I decided to dig out my bandsaw and see if I could get the blade back on, and stay on. After a few minutes of fiddling, it's back in action, and my test cuts with it (even though the blade is very old and dull) were neat and tidy on the foam core board.

Fortunately I have enough sheets where I can start again, and do things properly this time! It'll be a couple of weeks before I can really get back to it, but I'm looking forward to posting a finished pair that's worthy of this thread

 

[Skylar88]

All you really need is a sharp hobby knife and a steel straight edge.

Keep in mind that a foam board speaker will never look as good as a well finished wood one.

 

[Kokanee]

Hi X and other builders,

I have a lot of 1.75" and 1.5" extruded polystyrene rigid insulation panels left over from building our new house. This is the kind of rigid insulation that some people are using to experiment with the exciters and vibration modes. I do not want to try this at this point in time.

Is there any restriction on how thick the walls of the box can be if building with foam or for that matter how thick some of the insides can be to make it more sturdy. I would like to try some of this rigid insulation I have, cutting to size where necessary and sealing with glue or some other sealant. Look forward to peoples comments.

Myles

 

[xrk971]

As long as you maintain the internal dimensions you are on. Variations of 5mm won’t matter much.

 

[perceval]

Hi X and other builders,

I have a lot of 1.75" and 1.5" extruded polystyrene rigid insulation panels left over from building our new house. This is the kind of rigid insulation that some people are using to experiment with the exciters and vibration modes. I do not want to try this at this point in time.

Is there any restriction on how thick the walls of the box can be if building with foam or for that matter how thick some of the insides can be to make it more sturdy. I would like to try some of this rigid insulation I have, cutting to size where necessary and sealing with glue or some other sealant. Look forward to peoples comments.

Myles

I found it a lot harder to keep the inner dimensions accurate when using thick XPS foam.

 

[sabre66]

Hi I am interested in this project but I have a question
How do you think 0.53 k's are going to sound through a LM3875 based amp?
(I built a audiosector premium kit amp many years ago)

Thanks
Paul

 

[Skylar88]

I think you will be pleasantly surprised. Before I built the ACA, I used to listen to my dual 3FE25 mini Karlsonators (0.53) with a TDA7297 chip amp and B1 preamp. They sounded wonderful.

 

[sabre66]

Ah Cool
I forgot I also have a B1. Just looking to put a remote controlled attenuator in to it (too lazy to manually control it)
Time to free up some funds for this project and dust off my table saw.
Will take a bit though, too many projects and no time.

 

[xrk971]

Some progress photos of my new 0.53x dual 3FE25-16 Karlsonators that I am making. Going for a deep hand-rubbed finish with espresso brown stain and 14 coats of hand-rubbed lacquer. Final coat will be satin finish though. The K-apertures will be natural blonde satin finish BB ply. These are another birthday present for my wife (the usual present from a guy who likes speakers - fourtuantely for me, she has a need for them in multiple rooms and likes the sound ). Design is based on jhofland's plans of the set that he gave me.

 

[davetest]

Some progress photos of my new 0.53x dual 3FE25-16 Karlsonators that I am making. Going for a deep hand-rubbed finish with espresso brown stain and 14 coats of hand-rubbed lacquer. Final coat will be satin finish though. The K-apertures will be natural blonde satin finish BB ply. These are another birthday present for my wife (the usual present from a guy who likes speakers - fourtuantely for me, she has a need for them in multiple rooms and likes the sound ). Design is based on jhofland's plans of the set that he gave me.

X do the jhofland plans exist as plans we can copy?

 

[Skylar88]

Wow, that looks great, X.
A quality finish for quality sounding speakers.

 

[baswamin]

I completed my mini-k's which I gifted to my nephew on entering teens. Thanks XRK for this idea and guidance.

Thanks
Balaji

 

[xrk971]

Nice work, Baswamin! Those look great for foam core. How do you like the sound?

Pretty impressive gear collection you have too.