GTHill's Kappa Perfect 12VQ MidQ Build Thread

[GTHill]

Well, I started the build of the subwoofer designed and posted by avaserfi in this thread: http://forums.audioholics.com/forums/showthread.php?t=45528

My build will be a bit different as I will be adding my own flavor.

I am building it out of MDF for a few reasons:

- I have a ton (almost literally) of it lying around.
- It is almost 33% less expensive than cabinet grade plywood
- It is my first speaker build
- I don't think that MDF with my additions will be much of a hindrance to the sound. However, it is my first speaker build so what the heck do I know.

General notes about the build:

- I'm not using any mechanical fasteners for the wood part of the build.
- I'm using mortise and tenon with the Festool Domino. This is an incredible tool and provides a superior joint to almost any other, including screws.
- I have a few surprises that will most likely be viewed and probably are bad ideas, but we'll see how it goes.
- I'm gone on business the next few weeks so updates will be sporadic for a few weeks.

Special thanks to Andrew for the build plans!

Gene

 

[GTHill]

Here are some inital pictures. You can see the mortise and tenon joinery at work here.

 

[GTHill]

The is this morning. I wanted to test the strength of the joints so I set a 5 gallon bucket of water on the end of the port. This is the equivalent of 40lbs and this didn't even stress the joints. I was really impressed!

Gene

 

[GTHill]

In this picture I just completed the brace assembly and am lining it up for installation.

I cut mortises through the the port and then lined up the brace. I shot a bit of spray paint through the mortises to get perfect alignment on the tenons.

Gene

 

[GTHill]

This is a picture of the brace installed. As you can see, I rounded the intake portion of the port. In addition, I routed every edge that has airflow "around" it. Will it make a difference? I'm not sure, but it sure feels good to make it look good.

Gene

 

[GTHill]

I have primed it with BIN (spray can) which is a great for MDF. Painting MDF can be a challenge because the edges and routed portions soak up the paint and will expand the MDF. NEVER use a water based paint or primer on MDF. It will actually expand like raising grain. BIN is the best thing I've used so far and I'm very happy with it.

I have put a few more coats of primer on it since this picture was taken.

I'll cut the rest of the box soon (maybe tomorrow) and do a dry assembly. It is going to be imperative that everything be precise so there won't be any leaks or rattles.

Gene

P.S. The port is upside down in this picture. Sorry!

 

[Haoleb]

I am building it out of MDF for a few reasons:

- I have a ton (almost literally) of it lying around.

Your gonna be sorry! I'm glad I didnt go with the MDF simply because of the added weight. You might want to consider casters


I've been looking forward to someone else getting started building this subwoofer. I cant wait to hear what you think when its done!

 

[GTHill]

Your gonna be sorry! I'm glad I didnt go with the MDF simply because of the added weight. You might want to consider casters


I've been looking forward to someone else getting started building this subwoofer. I cant wait to hear what you think when its done!

I know that it will be heavy and I actually like that it is going to have a lot of weight. Actually, you will see when I get done, it will be even heavier than most people think.

Gene

P.S. Nice work on your build. It looks great!

 

[Haoleb]

P.S. Nice work on your build. It looks great!

I think yours is definetly shaping up to be quite a step above mine, I like the way you joined everything together. I thought about doing biscuit joints on mine but just decided to take the easy way out instead.

Any ideas what kind of finish your gonna put on this? I'd love to see someone do something like rosewood veneer that would look outstanding!

 

[GTHill]

I think yours is definetly shaping up to be quite a step above mine, I like the way you joined everything together. I thought about doing biscuit joints on mine but just decided to take the easy way out instead.

Any ideas what kind of finish your gonna put on this? I'd love to see someone do something like rosewood veneer that would look outstanding!

Another reason why I have MDF instead of "regular" wood is because I don't like a lot of wood look, especially on my home theater equipment.

I'm probably going to go with an automotive paint finish. Maybe... flat or satin black? Or... Ferrari Red.

Gene

 

[annunaki]

Another reason why I have MDF instead of "regular" wood is because I don't like a lot of wood look, especially on my home theater equipment.

I'm probably going to go with an automotive paint finish. Maybe... flat or satin black? Or... Ferrari Red.

Gene

I believe the term for Ferrari red is Rosa Corsa Red I could be wrong though.

 

[GTHill]

I believe the term for Ferrari red is Rosa Corsa Red I could be wrong though.

It's actually Rosso Corsa, but yeah you are right. I didn't want to post that because some wouldn't know what color I meant. I still have some left from the last panel touch up... hmm...

Gene

 

[gus6464]

It's actually Rosso Corsa, but yeah you are right. I didn't want to post that because some wouldn't know what color I meant. I still have some left from the last panel touch up... hmm...

Gene

What glue are you using for your sub? I saw that you recommended BIN for primer and I was wondering what would you recommend for paint? I am not looking for glossy or anything and just regular black.

 

[GTHill]

What glue are you using for your sub? I saw that you recommended BIN for primer and I was wondering what would you recommend for paint? I am not looking for glossy or anything and just regular black.

I'm using the original Titebond. I'm not a glue expert, but I will tell you this stuff is super strong. In my strength testing of the Domino joint, its always the wood that breaks before the glue or the Domino itself.

With proper sanding and primer, you can use spray can black from off the shelf. If you want to go high end, you can buy DuPont bumper and trim paint. It has a great satin look, but it is $10 per can.

I will probably go with automotive paint, but with proper prep work you can have a great looking sub with spray paint. It's all about budget.

Gene

 

[GTHill]

I cut the rest of the pieces for the sub enclosure this evening. I dry attached the bottom with Dominos. The bottom is going to be first piece installed permanently, but I have to line up all of the other pieces before permanent installation. I need to do that so I can pre cut all of the Domino mortises. This also provides a perfect view of how it will look on the inside fully assembled. I need to ensure that the braces and port has a tight fit to the outside walls. So far, it's looking good, but I won't know until I start fitting it together piece by piece.

I ordered all of the components that I will need to finish the project. I went with everything that Andrew recommended. I haven't added up the total bill yet, but I expect it will be around $800 or so. The upside is that when I build the next one, I can use the same amp and EQ, so it will only cost approx $300.

I will be testing this sub head to head against my Paradigm Servo 15. I'm excited to hear the results!

Gene

 

[Djizasse]

It's looking good
Rosso Corsa, a couple of varnish layers, some wax and quick detail.... hmmmm
I would really like to see that.

Keep up the good work

 

[annunaki]

It's actually Rosso Corsa, but yeah you are right. I didn't want to post that because some wouldn't know what color I meant. I still have some left from the last panel touch up... hmm...

Gene

I knew it was not quite right.

 

[Haoleb]

So any progress? Inquiring Minds want to know

 

[GTHill]

Unfortunately I work away from home this week and next so I haven't done anything more at this point. I did pick up some more tools (clamps and circle jigs) while I was here in Dallas so that will be helpful. I will be working on it tomorrow so we'll see how that goes.

My wife has informed me that UPS has showed up quite a bit so I guess the speaker, amp, EQ, OC705, and misc parts have arrived.

More updates to come this weekend!

Gene

 

[GTHill]

Well, I got home and unpacked everything and I'm still missing one box. It should be at my house on Monday, but I'm working out of town this week, so no real updates.

The box is almost put together, but I have a few design issues to work out before I finish. I'm off next week so that should free up some time for the project.

Gene