Adam's Kit81 Project

After a bit of research on home theater speakers, I finally decided on the Kit81 set from Adire Audio. It's a pretty simple DIY kit that includes a pair of 8" drivers, a pair of tweets, and all of the components to the passive crossovers along with a bunch of instructions and schematics. Seeing as how I liked my Adire car speakers so much, I figured I would give these a shot.

The first step was to pick the enclosure. Adire gives blueprints for sealed, vented, and transmission line cabinets. I ended up picking the vented for the added low end extension and ease of construction.

Before you can do anything you need the right tools, I built these with a 4x8 sheet of .75" mdf, a simple table saw, drill, dremel (with the router attachment of course), clamps, and a crapload of liquid nails.

The cutting went easily enough, table saws are like a gift from god. All of the large holes were cut with the dremel, and the port and tweeter holes were cut with a simple 2" hole saw. Afterwards I went in with the dremel/router and gave the port hole a 45 degree chamfer to make it a bit nicer looking

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After all the cutting, it's time to start the assembly. Again this went easily enough, load up the joints with liquid nails, line them up and put on the clamps, drill and screw, repeat.

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One cabinet mostly done, one to go

A simple 2" diameter and 4.75" long pvc port in the front panel gives the towers a 32.5hz tune, which will let them extend cleanly into the 20hz range without a problem. To mount the pvc I gave the 2" hole in the front panel a .375" deep notch on the backside for the pvc to slip into, similar to the way you flush mount a speaker into its baffle.

Both towers are nearing completion

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Everything looks good, so it's time to mount the front baffle onto each tower and sand the joints down

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And as it turns out, spring break simply isn't long enough to get much done and I kind of ran out of time, so I made the trip back to school with a pair of nearly completed and unpainted towers. Still have to build the crossovers, mount the crossovers and drivers, cut out a hole for and mount the terminal cups, and paint the towers. Looks like the painting and terminals are going to have to wait for summer, at least this gave me a chance to break the drivers in. And no, the flaming purple tub is not mine, but the ancient tv certainly is. Unfortunately I don't have any pictures of the crossovers, but they're not a work of art anyway. Just imagine a 6"x6" piece of plywood with a crapload of inductors, caps, and resistors mounted to it and you'll get the general idea.

Ah summer is here, time to get to work on the painting. On a side note, Liquid Nails is a major PITA to sand....but I finally got it done. I painted them using simple spray paint, 2 layers of primer and somewhere around 5-6 layers of semi-gloss black.

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And they're finally done, I think they turned out great. Of course this being my first "pretty" build there are a few imperfections, but all in all I'd say they were a success

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And one last picture of the final setup. I know it's a mess but hey, as long as it works...

 

They sound amazing, I'm a bit too lazy to do a full review right now, but I'll do a short one. They started off a bit harsh, but after many hours they broke in well and the tweets mellowed out. The bass goes easily into the high 20's and sounds very balanced. If I get a bit giddy with test tones I can get some port noise around tuning (as things are falling off my shelves), but for normal listening there's never a hint of whistling from the ports. The midrange sounds smooth and natural, and the treble is very detailed and for the most part laid back. At very high volumes the tweets can still get a little bright, but it's not severe and it's nothing a little EQing can't fix. The sub in that picture stays off normally, it's tuned a bit high for home theater use so it gets a little peaky around 30-35hz, and the towers go low enough to cover the whole frequency range without any problems anyway.

 

Update 9/24/10: I've finally decided to upgrade my towers. The Kit 81s have served me well for over six years, but it's time to move on. They have been great, and sound as good now as when they first broke in. Regardless, I've moved on to the Zaph ZRT 2.5s for my primary stereo setup. Perhaps I'll move the Kit 81s to a secondary sound system in another room, who knows.

 

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