Kitchen Cupboard 3-way Build

[Harpo]

I've been building seat-of-the-pants 2 ways since I was 12 (I'm 67 now), and having retired I thought I'd try a 3-way. I lack both the agility and space to handle large power tools nowadays, so these will be based on Klearvue wall cabinets. Yes, I know particle board is not ideal, but these are 3/4" and very solidly built. Baffles will be 3/4" plywood, interior will be braced and damped. Here's a list of the components with part numbers, followed by links for same:

PRV Audio 10MB800FT 10" Professional Midbass Driver 8 Ohm	294-2988
PRV Audio 15SW2000 15" Pro Audio Subwoofer​	294-3007
PRV Audio D260My-B Mylar Horn Compression Driver 8 Ohm	294-2992
PRV Audio 3DF400/1800 Three-Way Crossover Board 400/1,800 Hz	294-2869
B&C ME45 1" Exponential Horn 90x40 2-Bolt	294-622
Parts Express Gold Recessed Binding Post Banana Jack 5-Way Speaker Terminal	260-309
KLËARVŪE Cabinetry® 18"W x 14"D x 40"H Wall Cabinet - Box Only	4780022
KLËARVŪE Cabinetry® 18"W x 14"D Shelves - 2 pk	4783504
3/4 x 2 x 4 Oak Plywood Handi-Panel	1254541

​​
PRV Audio 15SW2000 15"
PRV Audio 10MB800FT 10"
PRV Audio D260My-B Mylar
B&C ME45 1" Exponential Horn
PRV Audio 3DF400/1800 Three-Way Crossover
18"W x 14"D x 40"H Wall Cabinet​

Power will be a 2x10w EL34 tube amp, high sensitivity is the goal. Available volume for the 15" is quite small at 3.8ft^3, but tuning to 38Hz looks pretty good in WINisd.

Though I'm very computer literate, I've never used anything but rudimentary calculations for speaker building in the past. I've become familiar with WINisd but I'm not sure it's really trustworthy, and I also have the DATS V3.

Any input or comments are welcome!

Kind regards,
Harpo

​

[Harpo]

Assembled, now on to testing and tuning!

[Steve Lee]

These look like they should sound very live!

[Harpo]

I'm very pleased so far, here's an earlier shot. The crossovers are temporarily mounted on the side to ease adjustments. I've also upgraded the horn drivers to the D260My-B, my original choice was having trouble keeping up. The mids live in their own internal box, and I'm trying a few different things for porting.

[Harpo]

I ended up with rather unconventional porting, but it works very well. I bought an assortment of nylon bushings and spaced the horn away from the baffle, providing a port in the front. Using different bushing lengths I tuned with DAT V3 until I hit my target 40Hz, which ended up taking 1" spacers.

This sounds and measures much better than the rear ports I was using, it gives a smoother path around the internal mid box (outline visible in post above).

[DrewsBrews]

Using kitchen cabinets, Why didn't I think of that! lol. Standard wall cabinets are 30" tall (12" deep) I think, but you can find 36"+ too


I love Menards. Ugh stop this.. I'm getting bad ideas now.

[Harpo]

Testing and tuning is done, now time to improve the looks. The baffle is oak plywood, I'm using oak veneer to finish the edges and cover the screw holes. The rest of the cabinets will be semi-gloss black, roller applied.

I was told on another forum that this combination of parts simply would not work with my 2x10w EL34 Chifi amp, that these drivers though very efficient would not respond to low wattage. It was also suggested that the high power crossovers would be too resistive. They were wrong, the little amp easily pushes these to 110dB with no issues and great sound.

I was also told these cabinets would not work, they would be full of buzzes and leaks, which was also incorrect. The sides, top and bottom of these cabinets is 3/4" particle board, the back is 1/2" but I added a layer of 1/2" plywood so it is now 1". The mid box (outline visible above the crossover in Post #4) is the only internal bracing. This mid box is lightly stuffed, and the woofer has 1/2" batting behind it. No buzzes, no leaks, no problems. I suppose if you applied the 1000w that these components will handle there would be some buzzing, but you would also be too deaf to hear it.

That brings us to design software. WINisd recommends a 40 cu ft box and tuning to 23Hz. Since I already own a refrigerator and don't need two more in my living room, I opted for a smaller box. Only 3.8 cu ft is available to the woofer in my design, and I tuned to 40Hz (which is also the Fs). They play down to 35Hz just fine, I'll post measurements soon.

Sorry for the rant, but I'm very happy I haven't met any such folks here. This seems to be a friendly place where experimenting is encouraged, and need not be backed up with endless armchair science. I'm all for simulation and measurements, but I've been building speakers for too long to place complete faith in them alone.

[Billet]

I like the contrasting oak trim around the edges. Nice work all around!

[Steve Lee]

It's nice to have a squared substrate/frame to built upon - makes assembly much easier than from scratch.
Good work.

[Harpo]

Stain and first coat of finish on, masked for painting. Also visible is the lining/stuffing I've selected, as well as my sloppy jigsaw work.

[Harpo]

One done, tentatively. I used different lining on the low end, so I'll test this one against the other and fine tune from there.

[DrewsBrews]

Lookin' good!

Check out pocket hole jigs. I got the Harbor Freight one years ago, but seems to have doubled in price since then. Basic Kreg brand ones are $20 if you already have a clamp and square. Simple to use once you get used to it. Would leave you with no screw heads to fill.

Dang I guess I'm getting too used to working on my build with a 12" woofer. I didn't realize those were 40" tall cabinets and 15" woofers. Guess I glossed over that. They don't look that big in the photos but those must be monsters!

[Harpo]

Lookin' good!

Check out pocket hole jigs. I got the Harbor Freight one years ago, but seems to have doubled in price since then. Basic Kreg brand ones are $20 if you already have a clamp and square. Simple to use once you get used to it. Would leave you with no screw heads to fill.

Dang I guess I'm getting too used to working on my build with a 12" woofer. I didn't realize those were 40" tall cabinets and 15" woofers. Guess I glossed over that. They don't look that big in the photos but those must be monsters!

The Kreg pocket hole tool is a great idea, I live about 10 miles from their factory and never even thought of that. I notice they make a lot of saw guides and clamps now too, rather tempting.

These are a bit large, they're 18"W x 14"D x 40"H . Klearvue makes even larger ones too, up to 36"W x 14"D x 40"H. This is the style I used: Klearvue Cabinets They even make shelves that are great for partitioning off inside.

[Harpo]

All done!

[unclejunebug]

Very cool idea using prefab kitchen cabinets for the enclosures! You'd never know by looking at them.