Speaker cab build

wilrecar77 · Post by **wilrecar77** » Sat Aug 03, 2013 3:48 am

Hey y'all. I found an Electro-Voice SRO 15" speaker at goodwill for $50 and figured it'd be cool to make a cab for it as a project. From what I've been able to find, it looks like one of the SRO's from the 60's or 70's rather than the later ones that were made under license by Kustom, though I don't think there's any real sonic difference between the two types. It's a big sumbitch and weighs around 25 pounds. Curiously, on the back of it rather than having a serial number, it just says "serial". I really dig the sound of it, it's extremely clean and has a sensitivity rating of around 103dB. I compared it side by side with the 4x12 loaded up with Celestion g12t-75's and it's just as loud at the same amp volume despite being rated at 8 ohms compared to the 4x12 at 4 ohms. I can dig it. It sounds pretty similar to the 4x12, in that is is very wide and clean, but it is a little bit less piercing. I guess the buzz word to use would be "sweeter" sounding.

I built the cab using plywood for the baffle and 1x12 pine boards for the rest. The interior bracing is made from 2x2. I didn't really feel like going through all the work to cut out a decent dovetail or finger joint using a jigsaw so it's just butt joints at the corners with lengths of 2x2 keeping everything square and rigid. I did the covering with some tan canvas I found on amazon and 3m spray adhesive. I wanted something made of a natural fiber so that whatever I use to lacquer it with will be able to soak in. I haven't lacquered it up yet, but I ought to be doing that soon. I haven't decided whether to use polyurethane or bondo resin but I'm leaning towards the bondo because I have some left over from another project and that shit cures up rock hard. On one hand, the polyurethane ought to be flexible enough not to crack if the wood expands or contracts, but the pine is so soft that I feel the bondo + fabric might be a bare minimum for abrasion resistance. It looks a little boring so I might get a friend to paint up the outside before I lacquer it. It's covered in canvas after all!

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It's 23 1/2" tall, 23 1/2" wide, and 11 1/2" deep. I still need to get some corners for it and figure out the handle situation. I think I'll go for the surface mount flip out type on either side but I'm not sure yet. All in all, the project has been around $120 so far, and I consider that to be pretty good being that a new speaker isn't much less than that.

Dave · Post by **Dave** » Sat Aug 03, 2013 11:26 am

Lovely work sir! Thanks for sharing, I love seeing all the steps!

wilrecar77 · Post by **wilrecar77** » Sat Aug 03, 2013 1:31 pm

Thanks man! My upholstering could be better, but it looks pretty good from the outside. I'll try to get a picture of the back of the speaker later today.

HNB · Post by **HNB** » Sat Aug 03, 2013 5:32 pm

Nice work!

wilrecar77 · Post by **wilrecar77** » Thu Aug 15, 2013 5:24 am

So much for anything getting done "later today"! Oh well, in the meantime, I ordered some flip out handles and corners from amazon. I still haven't polyurethane-ed it. It's been crazy humid and rainy out here this summer. Here's some pictures of the cab in it's current "finished" state.

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The handles look skewed for some reason. The metal base is lined up and square with the lines of the cab, but the handle itself sits at an angle in the hinge assembly. I think it's because of how they did the spring inside. It kind of throws off the look of it, but they function perfectly and that's what matters.

I dig the corners. They're smaller than I thought they would be, but again, they work and that's what matters. The whole thing has a different vibe than most cabs I've seen.

When I get around to doing the polyurethane I'll do another update and I'll try to get a demo of how it sounds. Again, thanks for the nice comments. I'd love to see more cab builds on the forum! I really like that feeling of looking at something I made and being proud of the fact that it works and I made it. I imagine many of the people on this forum are similar with making guitars. I started this project because I saw a cool speaker, but I've noticed that many people on the forum have problems transporting cabs and amps on public transport because of size. Why not make a custom cab that fits your needs?