Damaged Goods - TSCM type enclosures for the wet Klipschorns

[garyeanderson]

Damaged Goods - I got some plywood to enclose the backs of the wet Klipschorns

Monday 11-29-2010

I have been thinking of this option for a while. My room is a square of 17 foot 3 inch and although the corners are good. The house has settled an inch or 2 in one corner since I rebuilt it in 1983 so the corners aren’t all that plumb and true. Rather than fix the problem it sounds like a good excuse to enclose the backs of one of the sets of Khorns that arrived this year. I wanted to do it on the cheap and was thinking about MDF but I haven’t worked with it and Lowes has it for a decent price of $30 a sheet. Decent hardwood plywood is around $50 from the same source and Boulter Plywood in Somerville seems to have it for more money but may be a better quality. I figured I need 3 sheets to do the pair and started looking at the TSCM threads on the forum to get a good idea on what Klipsch did. I also read the posts by Indyklipsch, Dean and Greg about their exploits with klipschorn backs. So with that bit of knowledge in hand I did what I usually do when its time to go shopping and started hunting around on craigslist. I started searching for the terms plywood and birch and didn’t find much but did a search on sheet and got a hit down in Rhode Island. Seems a Cabinet manufacture had collected and stored a bunch of its damaged goods in a building and never got back to it to do anything with it and contracted someone to dispose of it. $5 a sheet for hardwood veneered MDF and some "lumber core" plywood for a bit more. I thought about it a bit and decided by the time I got there to look at it and if I didn’t buy anything I’d be out $20 just in looking. It wasn’t until I saw a Roberts 720 tube amp tape deck for $40 on the other side of Providence that I figured it be worth the trip to see the "lumber core". So Saturday I made arrangements to meet the seller of the Roberts 720 in Attleboro yesterday and also got a phone number for Steve with the "Lumber core" in Cumberland RI about 10 miles from Attleboro. Steve and I met about 10 am and he showed me the MDF and I wasn’t to impressed but the "lumber core" turned out to be 9 ply ¾ inch (7 core pieces) with White Ash on one face and Birch on the other. Two full sheets of 97x49 inch and 2 not quite half sheets. He also had 2 full sheets of fork lift damaged Mahogany 4x10 ft. ¾ inch (7 core ply) that we loaded into the back of the pickup. Total price for the plywood was $40, the total for the trip was about $100 for the tape deck and lumber.

There is enough of the White Ash but not quite enough of the Mahogany to do a TSCM clone of the Khorn bottoms. I need to wait for some warmer temps to do any work, as it will all be mostly done outside.

So fast forward 2 weeks yesterday Saturday December 11^th

I made arrangements on Wednesday with a friend of mine to help cut the White Ash Plywood. Well lets call it what it is, I brought it over to his Cabinet shop with my drawings and I helped with the Layout holding the straight edge in place and answered questions. He proceeded to mark the parts out on the plywood and do all of the sawing.

In 2 hours he had the 4 tops, 4 sides and 2 backs cut and were loaded in the back of my pickup. It would have taken me all day at least and I probably wouldn’t have got to it till spring.

Today I got off to a slow start as usual and wasn’t going to start but the clouds moved in so I got the tape measure out and marked some hole locations on one of the top trapezoids. The next thing I knew I had the other trapezoid screwed to the bottom of on of the Klipschorn bass bins that I bought on ebay in July. These were the $500 beauties that play pretty nice but look like hell. I tried to center the back off of the bin but it wasn’t working out so I centered the front of the bin with the openings at or as close as I could to 13 and 5/16 inches on both sides. I got as far as putting 4 screws into the bottom to lock it into place so it wouldn’t move around and then 2 more screws into the new tailboard. I need to make a run to Lowes in the morning and get some more screws before I start to drill more holes. The pictures don’t look like much but I think it will work out O.K. The only thing we didn’t cut were the side braces and I want to do those after the bass bins are in the enclosure. I am not sure about the hatch opening yet, I am thinking that I am not going to cut them, if I need to access the Woofer, I will unscrew the bass bin and slide it out. I made the height about a 1/16 of an inch extra so that its possible to remove the bass bin from the enclosure, I guess I see if it works, if not I can always plunge cut the access doors later.

[garyeanderson]

The photo in the previous post is a trial just to see what it sounded like and just how big it was, it’s pretty large. One side was 44 inches and the other was close to that. They are just clamped in place and nothing too serious. The plywood was already cut when I bought it so I just moved it upstairs and rigged it the best I could. The sound was O.K. and it warranted a larger investment in time.

[garyeanderson]

The backs are 11 3/8 wide long point to long point both edges mitered at 45 degrees x 38 ½+, the sides are 33 1/2 wide x 38 1/2+ tall with one edge mitered at 45 degrees. The trapezoids are 24 inches deep and 57 ¾ inches with the both ends nibbed back so the sides come square at the fronts.

[garyeanderson]

full view of the trapazoid top

[garyeanderson]

One last picture of today’s limited progress.

[jacksonbart]

That lamp really ties the room together.

[garyeanderson]

The lamp is a freebe from my late aunt, It still has the dust on it from this summer when I building the heavyweight La Scala bass bin clones. Anyway I had a number 2 pencil that I was marking the location of holes on bottom of the trapazoid so I could start at the bottom of the foundation and hopefully get it square. I couldn't see the X's I had just made to drill the holes. The lamp has a 250 watt bulb so a blind guy like me can see where he is about to screw up... Glad you liked it.

[garyeanderson]

I made a little progress on of the enclosures. Not to sure what’s has happened but the one side needed to be trimmed. There was a problem with one of the sides in that it had a cup to it and when the miter was cut it lifted in the center. Oh well I had the extra length anyway so I got the skill saw out and re-cut the 45 degree miter and trimmed of the bowed end. Look ok to me so I guess I’ll keep drilling a few more holes before I take it all apart for gluing. I got some more masking tape and paper towels so that I can be ready for any glue rain. I won’t be using all that much but I’ll tape and paper off the white ash just the same. I may get to it tomorrow if everything continues to go as planed.

[seti]

That is really cool. I need to find a pair of khorn lf bins soon

[sootshe]

Very interesting..............progress is coming along nicely..........I'll be very interested in your thoughts of the sound when you have them complete.

Great job. []

[garyeanderson]

Hi Seti

Better hurry, I seem to be finding all of the local problem Khorn's...

I have never been known as the patient type of person. I no sooner put the last screw in the enclosure I spun her around, flipped the HF cab upside down, got some longer thermostat wire that was sitting over in the corner and wired the network to the bass bin. I proceeded to toss Hot Tuna and played "Sea Child" and a few others at moderate volume. I have (4) 1 and 5/8 inch screws holding the bottom of the bass bin and (6) more 2 inch screws into the tail board but it still was putting out significant bass and it was 30 inches off of the solid wall and a bit more than a foot in front of the window. The top and sides were vibrating pretty good so things can only get better when its glued, screwed and the braces installed and the top secured to the bass bin.

[garyeanderson]

I am still not exactly sure what I did wrong but there are definitely problems with the cabinet that I am building. My equilateral trapezoid is not equilateral. I am out on the diagonals by a half an inch. Oh well it will still work just fine but its making fitting the braces a bit of a pain it the butt. Anyway I managed to get the braces cut for the one cab, I am not sure that I can fix the issues even if I can identify where I messed up so I will concentrate on this enclosure and worry about the next one later. I guess that’s what I get when you buy $20 worth of Ash plywood and you only get just enough, The problem was I got all there was and the choice was to make something else or wing it and pray I got it right. Well I didn’t so now it’s time to just make it work.

I made a pattern for the braces last night and I tried it on both sides, unfortunately it didn’t fit both sides. So this morning I re-did the patterns and made a couple of templates out of birch plywood. They were only fair, so I made some notations and took the cut-offs from the trapezoids and headed over to the folks house where the table saw is, the templates were made with a skill saw and looked like they had been cut out with a tree chipper. Seeing I had the grain all going across I wanted these the same orientation. That presented a problem. I forgot that they needed to be mirror images of each other to look right and due to the way the cut offs worked out they weren’t quite large enough, Luckily I caught myself before I screwed up and only had to modify the shape of the braces. Instead of being un-equilateral trapezoids in shape like an airplane tail, I trimmed off a backs and turned them into diamonds. I got them home and two fit nicely and two needed some more trimming to balance out the look. So it’s too late to glue today so I guess I’ll take the rest of the day off. More as thing develop…

[garyeanderson]

One more picture of the cab with the braces fitted. There are no screws in them yet but they might work ok. If there is still too much vibration, I can run a vertical brace in behind out toward the ends on the left and right hand sides.

[twistedcrankcammer]

Gary,

Looksjust like a TSCM Bass Bin...

Roger

[garyeanderson]

Hi Roger

I want to thank you and Michael for the photos in the Klipsch Pro section.

http://forums.klipsch.com/forums/t/116843.aspx

It helped me a lot to decide to build them, and also how to build them. I guess that if I had been planning to paint them black I would have laid them out differently. I got a good price on the Ash plywood and I guess I worked it the way I did so that the top had no end grain showing. Anyway I think they will work nicely and when I fix the fronts of the bins they will look good too.

I have been doing some measuring and I have found my screw up. I am going to leave the first one the way it is as I don’t think I could fix it and have it look as good as it does now. Luckily when we laid them out all of the tops and bottoms were identically flawed. Some how an extra ¾ inch was added. We must have measured to the wrong side of the ¾ inch plywood. I guess I will re-cut the remaining top and bottom as its only one cut, the sides will need to be shortened too. I will update the dimensions that I posted earlier when I get it straightened out and verify that they assemble more easily. Who knows maybe someone else will want to move really heavy speakers around. I might even do another pair for downstairs.

[twistedcrankcammer]

Hi Roger

I want to thank you and Michael for the photos in the Klipsch Pro section.

http://forums.klipsch.com/forums/t/116843.aspx

It helped me a lot to decide to build them, and also how to build them. I guess that if I had been planning to paint them black I would have laid them out differently. I got a good price on the Ash plywood and I guess I worked it the way I did so that the top had no end grain showing. Anyway I think they will work nicely and when I fix the fronts of the bins they will look good too.

I have been doing some measuring and I have found my screw up. I am going to leave the first one the way it is as I don’t think I could fix it and have it look as good as it does now. Luckily when we laid them out all of the tops and bottoms were identically flawed. Some how an extra ¾ inch was added. We must have measured to the wrong side of the ¾ inch plywood. I guess I will re-cut the remaining top and bottom as its only one cut, the sides will need to be shortened too. I will update the dimensions that I posted earlier when I get it straightened out and verify that they assemble more easily. Who knows maybe someone else will want to move really heavy speakers around. I might even do another pair for downstairs.

Gary,

I wouldn't paint them Black either, in fact, if I had the equipement, I would venner all 7 of them, maybe all nine.

Congraulations on the bravery it takes to undertake such a prodject in the first place. [Y]

Roger

[garyeanderson]

Yesterday I didn't get a lot done but I did manage to drill a dozen holes in the two sides to secure the four braces, I even got the screws in. I played a couple more tunes after rearranging the La Scala clone bass bins. This was one of the reasons for enclosing the backs of the Klipschorns as I couldn’t place the clones back against the wall without blocking half of the sound of the Khorn bass bins. I still need to glue the first assembled enclosure up but I think that will happen when all of the parts are drilled and fitted to both bins.

I spent about 4 more hours on the set of parts for the second Klipschorn enclosure today. I ended up re-cutting the trapezoids on one of the equilateral edges where the layout was messed up. They are now more or less equilateral. The sides needed to be shortened too. When I put the two side back to back they were parallel but the mitered ends we off in opposite directions so I squared up the miters up first. I then shortened the overall length to 33 inches. So here are the final dimensions that I am hoping will work out a bit better than the first set, at least in the ease of assembly.

The backs are 11 3/8 wide ("the back width plus a bit" = 9.25 + {"2 sides at 3/4 inch" = 1.5 x square root of 2}) long point to long point (10 inches showing on the outside) with both edges mitered at 45 degrees x 38 1/2+ tall, the sides are 33 wide to the long point with one edge mitered at 45 degrees x 38 1/2+ tall. The trapezoids are 24 inches deep and 57 inches with the both ends nibbed back so the sides come square at the fronts. So the layout on the trapezoid is measure out 24inch along the length, 34 inch and the last point of the layout is 58, with the ends of the trapezoid nibbed back the final overall length becomes 57 inches. 3 full sheets of plywood or MDF is needed if nothing go'es wrong. I’ll let you all know how it works out when it happens. I guess I posted the last photo for a while, my beater Olympus camera stopped focusing just like the first one I had. It may be a while before I get it replaced.

[tromprof]

I have always wondered what I would do if I ever moved and lost my corners for my K-horns. Now I know, your bass bins look fantastic!

[garyeanderson]

I have always wondered what I would do if I ever moved and lost my corners for my K-horns. Now I know, your bass bins look fantastic!

Hello Tromprof

Thank you for the complement, I think that the K-horn’s speak for themselves. My corners are fairly good but I needed to stuff around the HF cabs to get a good seal and looking at the corner from beside the bass bins I could see ¼ to 3/8 of an inch of gap between the walls and the tailboard. It was even more around the baseboard of the room so I thought that for some short money I could do this winter project upstairs where it’s warm and hopefully see what I was loosing. The first enclosure is a bit of an oops and may not be 100% of its potential because of my screw up in the figuring and layout translation. The enclosure is 45 degrees on one side but the other is ¾ of an inch out of being a 90 degrees to the other side. There are some leaks too and so far I have only screws holding it together but it still delivers on the bass side. I this is with 10 screws securing the bass bin (6 in from the tailboard and 4 on the bottom) in the enclosure. At the moment it is 2 feet off the back wall abutting the window, this is probably it home as the La Scala bass bin clones are now clear of the Klipschorn bass bin final air path.

I have been working on the other K-horn bass bin, this is the more water damaged of the two bins. It had some fairly bad delaminating of the lower side ply’s, the first ply was separated 4 to 5 inches up the side and several more layers were delaminated near the back. I used about 2 ounces of yellow glue that I pushed into place with a 7-inch nail file and then put a layer of wax paper over the plywood. I had cut some ¾ inch thick corner reflectors that were not used on the La Scala clone project and that seemed to be a good piece to spread the load that I was going to exert on the to K-horn bass bin. The next was a 1 ½ x 2 ½ bit of maple right on top of the spreader plywood to give it some pressure. With another block of maple just like the first I wrapped a 2 inch wide ratchet strap around the bottom of the bin. I ended up putting nearly all of my weight on the ratcheting handle to get some glue squeeze out. After 3 or so hours I removed it all and I was pleased to see that it worked quite well. It was the worst of the problems other than the missing bits of birch on the front, one of those is being glued as I write this. I am not expecting them to look 100% but If I am to spend more the $50 on them I want them to look pretty good. If I can get the fronts to be flat then I’ll invest in some Ash veneer and tape the edges of the plywood with Ash too. Come spring I’ll recap the networks if I have the money…

[Tom Mobley]

>>> "Some how an extra ¾ inch was added. We must have measured to the wrong side of the ¾ inch plywood."

I hate it when that happens. I do stuff like that pretty regularly. I'm blaming it on old age.