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About two years ago, I decided I wanted to build a pair of MTM speakers using the Dayton RS series mid woofers. I don't recall my exact reasoning, except that it seemed to me there are lots of designs using this formula, so I think I figured there must be something to it. If I remember correctly, it seemed the most common formula was to use the Dayton RS tweeter, which I think was discontinued around that time. So for those poorly-remembered reasons, and possibly others as well, I landed on Curt Campbell's Slapshot MTM design, which uses two Dayton RS180-P midwoofers and a Morel CAT 378 tweeter. I bought the plans from Rhythm Audio Design (though now I cannot find the plans listed on their website). My wife bought me the drivers for Christmas 2018, and at that time my parents gifted me crossover parts. I had some birch plywood at my parents' house that I bought 20 years ago for building a 2x12 speaker cabinet for guitar (yes, literally 20 years ago, right after I graduated from school and was still living with my folks!).
I sat on the plans and parts for two years, only recently finally getting the motivation to put it all together. I've built a few pairs of DIY speakers, but, excepting for the guitar speaker cabinet and a Paul Carmody Isetta, I've never done all the wood cuts myself, and built from flat-pack kits. My woodworking skills are mediocre at best! I don't have a table saw, and all the straight cuts were done on a too-small table, using a saw clamp-guide and circular saw. I bought a plunge router just for this project. I didn't have enough 20 year old birch ply to complete the project, so bought some more birch ply from the local hardware store. I think I counted five layers, I know it's not the best birch ply. (I once got a flat pack kit from Planet10, they used the 13-ply Baltic Birch wood that comes in 5x5 sheets - really nice.) After five sides of one box was glued together, I realized there was a slight bow to the side panels. I spent an embarrassing amount of time with Bondo and the belt sander!
Almost all the speakers I've built have been finished in Duratex. I like a very plain, utilitarian aesthetic - Duratex fits the bill perfectly. It's easy to use, has a mild non-offensive odor, and cleans up with water. The textured finish also helps cover up my lousy woodworking!
A special thanks to bungelow_ed ! The Slapshot MTM plans I got from Rhythm Audio Design included drawings for both the stand-mount MTM, and also bungelow_ed's floorstanding MLTL variant. My original plan was to build this floorstanding version, and Ed was very helpful in clarifying some of the details on the plans. Thank you Ed! But my wife veto'ed the MLTL version, and insisted I stick with the smaller stand mounts.
Also, a big thanks to the folks at Rhythm Audio Design. The plans were missing a few details, and despite me buying them over two years ago, RAD was still very helpful in promptly and thoroughly answering all my (numerous) questions.
These speakers are going in our basement. As you can see from the pictures, the basement is unfinished. But it still gets a lot of use by my family. Because it's unfinished, it's basically one big open area. Previously I was using a pair of Paul Carmody Speedsters. The Speedsters sound great! But I don't think anyone will be surprised to hear that they fall a little short when it comes to filling a large open area with sound. In this role, the Slapshots sound great! They certainly sound "big". I like fairly modest volume levels, but in this basement, to have an "even" sound in the whole area, the volume needs to be turned up a bit. The Slapshots sound very "effortless" to me: the sound is very clean, to the point where I want to play them louder than I normally like. Instrument separation is wonderful. They also don't seem very directional, especially compared to the Speedsters. In fact, I can stand to the side of one speaker (i.e. in the same plane as the pair) and it really doesn't seem all that different from standing in the sweet spot.
Here's a clamping shot. Only after I had it all glued up did I realize I didn't have enough long clamps as I wanted to do the front-to-back clamping. So I rigged up the strap you can see in the picture to provide some front-to-back tension in the middle.
I pretty much followed the plans to the letter, except for the internal bracing. The plans called for cutting a couple "U" shaped pieces to go inside. I was afraid I wouldn't be able to pull of the necessary cut precision to do this, so I instead glued in some 1-inch dowels for bracing.
Here's one of the front baffles. I used a Jasper jig with my router for the circles. I free-handed the extra bit for the tweeter, and also free-handed the woofer vents.
Here's a shot of the inside, with crossovers and foam lining. I also stuffed these generously with poly fill.
Next post will have pics of the finished speakers, since there's a five attachment limit!
I sat on the plans and parts for two years, only recently finally getting the motivation to put it all together. I've built a few pairs of DIY speakers, but, excepting for the guitar speaker cabinet and a Paul Carmody Isetta, I've never done all the wood cuts myself, and built from flat-pack kits. My woodworking skills are mediocre at best! I don't have a table saw, and all the straight cuts were done on a too-small table, using a saw clamp-guide and circular saw. I bought a plunge router just for this project. I didn't have enough 20 year old birch ply to complete the project, so bought some more birch ply from the local hardware store. I think I counted five layers, I know it's not the best birch ply. (I once got a flat pack kit from Planet10, they used the 13-ply Baltic Birch wood that comes in 5x5 sheets - really nice.) After five sides of one box was glued together, I realized there was a slight bow to the side panels. I spent an embarrassing amount of time with Bondo and the belt sander!
Almost all the speakers I've built have been finished in Duratex. I like a very plain, utilitarian aesthetic - Duratex fits the bill perfectly. It's easy to use, has a mild non-offensive odor, and cleans up with water. The textured finish also helps cover up my lousy woodworking!
A special thanks to bungelow_ed ! The Slapshot MTM plans I got from Rhythm Audio Design included drawings for both the stand-mount MTM, and also bungelow_ed's floorstanding MLTL variant. My original plan was to build this floorstanding version, and Ed was very helpful in clarifying some of the details on the plans. Thank you Ed! But my wife veto'ed the MLTL version, and insisted I stick with the smaller stand mounts.
Also, a big thanks to the folks at Rhythm Audio Design. The plans were missing a few details, and despite me buying them over two years ago, RAD was still very helpful in promptly and thoroughly answering all my (numerous) questions.
These speakers are going in our basement. As you can see from the pictures, the basement is unfinished. But it still gets a lot of use by my family. Because it's unfinished, it's basically one big open area. Previously I was using a pair of Paul Carmody Speedsters. The Speedsters sound great! But I don't think anyone will be surprised to hear that they fall a little short when it comes to filling a large open area with sound. In this role, the Slapshots sound great! They certainly sound "big". I like fairly modest volume levels, but in this basement, to have an "even" sound in the whole area, the volume needs to be turned up a bit. The Slapshots sound very "effortless" to me: the sound is very clean, to the point where I want to play them louder than I normally like. Instrument separation is wonderful. They also don't seem very directional, especially compared to the Speedsters. In fact, I can stand to the side of one speaker (i.e. in the same plane as the pair) and it really doesn't seem all that different from standing in the sweet spot.
Here's a clamping shot. Only after I had it all glued up did I realize I didn't have enough long clamps as I wanted to do the front-to-back clamping. So I rigged up the strap you can see in the picture to provide some front-to-back tension in the middle.
I pretty much followed the plans to the letter, except for the internal bracing. The plans called for cutting a couple "U" shaped pieces to go inside. I was afraid I wouldn't be able to pull of the necessary cut precision to do this, so I instead glued in some 1-inch dowels for bracing.
Here's one of the front baffles. I used a Jasper jig with my router for the circles. I free-handed the extra bit for the tweeter, and also free-handed the woofer vents.
Here's a shot of the inside, with crossovers and foam lining. I also stuffed these generously with poly fill.
Next post will have pics of the finished speakers, since there's a five attachment limit!
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