Tritrix HT Build with Ceiling Bracket Design

[Soundslike]

Re: Tritrix HT Build with Ceiling Bracket Design

The brackets feature adjustment knobs at the vertical pivot points, on either side of the speakers. In the photo, I've drawn an outline of the four knobs, and laid out an array of holes that will become grooves on the circumference. The outer line of the circles is to locate the center of the holes I'v drilled, and the inner line is the cut line. The result will be shallow grooves, rather than half diameter grooves. The drilling locations were laid out with a protractor. Next, I'll use the countersink in the drill press chuck to add a bevel to the holes.

These knobs will be functional, but mostly decorative. Anything, from a wing nut to a 1/4 20 nut could be used.





In the next photo, you can see the beveled holes, and you'll also notice that I've recessed the center area of what will be our knobs. This recessed/ depressed area was cut with a large Forsner bit. This feature makes the knobs more interesting visually, and could be used to make the them more attractive by adding a round thin metal disk trim piece. Polished brass cut from a door kick plate comes to mind.

Getting all of the grooves beveled (using the countersink bit) to the same depth is important for appearance sake, an easy task with a drill press if the depth stop is used. I'm cutting out a recess that will flush fit a 1/4 20 nut, which will provide the threads needed for the knob to function. The nuts will be glued in with epoxy. The nuts must be on the outside of the knob where they will be pulled into the knob with increasing force as it is tightened -- if placed on the inside the knob will be entirely dependent on the epoxy glue holding the nut in the recess.

The tool I'm using to cut the recesses is, as I'm sure you can tell, one that I made for this task. I ground the chisel blade out of an old hacksaw blade. Not particularly difficult, if you have a bench grinder. Bench grinders are cheap and they're a basic tool for every shop.

When I make knobs the next time around, I'll probably try to improve on the design. These are working well enough, on the finished brackets, but it wouldn't be difficult to twist the nut out of the recess. As I mentioned last night, MDF is rather soft below the surface so it's a good idea not to apply too much force to the finished knob. I have several alternatives in mind, such as welding a nut to a circular shaped piece of sheet metal, or saturating the MDF in the area around the nut cutout with cyanoacrylate (superglue). I'll try to remember to knock out a drawing illustrating the knob modifications I have discussed here, later in the thread.
http://en.wikipedia.org/wiki/Cyanoacrylate



The knobs were next rough cut to shape on the bandsaw, then sanded to a round shape using the same process described earlier. Next, a long 1/4" bolt was inserted through the center hole of the knobs, and into the drill press chuck. Using the drill press for a lathe, the knobs were turned, shaped and sanded using wood rasps, files, and sand paper.

[its_bacon12]

Re: Tritrix HT Build with Ceiling Bracket Design

Your thoughtfulness in planning it out like you have is incredible. You did everything right that I'm sure most of us don't have the patience to do!

What a build thread! Thank you for sharing!! Bookmarked for later date on how to properly execute a build

[Soundslike]

Re: Tritrix HT Build with Ceiling Bracket Design

I think I honestly shed a small tear...

All those TriTrix enclosures...all that attention to detail...the crossover looks awesome...I think I need a hug...:D

That made my day -- I'm still chuckling...

[greywarden]

Re: Tritrix HT Build with Ceiling Bracket Design

Holy crap that's a rediculous amount of work! Wow! Fantastic build again!

[Soundslike]

Re: Tritrix HT Build with Ceiling Bracket Design

After a little experimentation, I settled on a design for the decorative parts of the bracket. In a drawing program similar to Corel, I sketched several different designs until coming up with one for the strap covers I thought would look okay. I then cut out four blanks and cut a channel-like recess in what would be the back sides, to conceal the vertical straps. After tracing the outline of the form in two dimensions on the blank I began cutting on the bandsaw. I first cut the the overall shape as viewed from the front, then taped the pieces back together so the workpiece would stand on edge while I cut the profile shape. The next photo shows the taped together blank being cut along the profile line.



This is a blank after the two cuts have been made. Note the channel I referred to earlier. The bottom piece is waste.



Next, I used a Forsner bit on the drill press to bore a circular recess at the top that would hold decorative discs I hoped would make the covers more interesting. Holes were also drilled for the wood/metal dowels at the pivot point, and the threaded rod where it exited the horizontal pipe. After sanding the profile cut, the pieces were bolted together for sanding on the spindle sander. Bolting the pieces together into one unit, made it possible to sand all pieces into identical shapes (as viewed from the front).



Here we see the final shape of the strap covers, with the decorative discs. The final shape was achieved by careful use of a wood rasp and a flexible sanding block. The decorative discs were made in the same manner described in a post yesterday, but with a recessed face cut using the drill press as a lathe. If you look closely, you can see that the MDF has taken on a rougher surface than we are accustomed to seeing. That's because MDF is much harder on the surface, and when the sub surface is exposed, it doesn't have the same smooth look and feel. It looks, and is, softer and much more absorbent. But as we will see, it is up to the task if finished properly.



Here's a better view of the profile. Looks a little like a dog bone, doesn't it...

I think I'll take this up again in the morning...

[Soundslike]

Re: Tritrix HT Build with Ceiling Bracket Design

This photo shows the bracket assembled, but bare nakid... Well maybe not completely nakid; I've used masking tape to cover the brass plated pipe to protect is as much as possible from dings and scratches. I got the pipe from a home center where they were getting rid of slow moving stock. It was made for a ceiling fan -- one of those long extensions that lowers the fan. I think I paid three bucks for the pipe. I rounded the top and bottom of the two vertical straps for appearance sake. The threaded rod will be trimmed later. I typically wait until I'm sure about the length before trimming -- once it's gone, you can't get it back...



I imagine most everyone knows what steel strap and all-thread rod is, but for those that haven't used it before, I gottcha covered. You'll notice the layout marks scratched into the strap. The top line marks the final width of the piece, and the crossed lines mark the location where the pass through hole will be drilled. When you're working with metal, be sure to drill holes before cutting the material into small pieces. Drill presses tend to grab metal and a lot of thrashing around can result. Larger pieces are easier to hold on to. By the way, when purchasing all thread rod, skip the metals department and go over to the electrical department. There you'll find long lengths of rod intended for hanging electrical conduit, fixtures, etc. It's much cheaper..




I think I mentioned that there are a lot of MDF discs in this bracket project. Here's one of eight I made for filling the PVC pipe column.


In this next photo, you can see the two lengths of PVC pipe that will be used for the column, along with the discs that will be glued inside to make the column solid. I used Titebond (wood glue) to glue the discs together, but the resulting assembly will be glued to the PVC with epoxy. The PVC pipe was cut using a mitre saw fitted with a blade that I can afford to dull.



I wanted to make sure the MDF discs were perfectly aligned with each other while the glue dries. To achieve that, I first applied glue to the individual pieces, then pressed them together inside the PVC that was to become their permanent residence. After about 20 minutes, the glue sets up enough to allow removal of the clamp, and removal of the stacked and glued discs from the PVC. Another trip to the disc sander cleans up any irregularities and the stacked discs can be glued into the PVC with epoxy.



Next, I needed to cross bore a 1" hole through the columns, through which the horizontal pipe would be fitted. This had to be accurately done, otherwise the the bracket would end up crooked, and the speaker would hang as though it had just been through a long overnight party with a bunch of rock stars. I made the jigs you see in the photo to hold the column in position during the boring process. The lines you see marked on the PVC and vertically down the bracket, are to determine the centerline of the column where the hole will be bored, and to make it possible to spot any shifting of the part that might occur. Creeping into view at the top of the photo, you can see the Forsner bit I'll use to bore the hole. The tops of the jigs don't fully enclose the PVC at the top to allow room for the Forsner bit.




In this photo, I'm boring through the PVC. Notice the large handscrew clamp used to hold everything in place.



Here's what the finished piece looks like:

[Soundslike]

Re: Tritrix HT Build with Ceiling Bracket Design

Five of the eight speakers in this build will be used in home theater (HT) for my daughter and her family. Two will go to my son and his family for their two channel system. In the HT system, sealed variants of the Tritrix design will be used for the center channel, and for the L & R rear surround channels.

The drawing below shows the design I came up with to suspend the surrounds from the ceiling. We opted to mount the surrounds on the ceiling because of the open design of the family room/kitchen where the system will be installed. There are no other suitable surfaces on which to mount the speakers, in the near vicinity of where the audience will be seated. And owing to the often mentioned SAF, mounting on pedestals wasn't going to work -- they would look rather like wood stoves sitting just behind the sofa.

Normally, one would probably opt for smaller surrounds in a situation like this, but a design with similar voicing would be necessary. Curt and Wayne's MTs would work fine, but would end up costing about the same as the Recession Destroyer kit and, I'd still have to build a single MTM for the center channel. Another factor in the Tritrix's favor was the vertical dimensions of the two -- the horizontally mounted MTM would fit closer to the ceiling. And honestly, I thought they'd look pretty cool and business-like up there.


The decision to go with the Tritrix speakers, meant I'd need a sturdy mount. I wanted to come up with something that didn't look like it was derived from brackets in the home shelving bin at Home Depot, or made by a blacksmith shop. Yesterday, I wrote about what I believe to be the two approaches to ceiling mounts, and the balance requirements for adjustable mounts. These mounts needed to be adjustable with two pivot points. These requirements would make it very tough to design something made of wood with adequate joint strength. Simple MDF construction would be out of the question. I wanted to be able to sleep at night knowing that these surrounds weren't going to come crashing down.

After giving the matter some thought, I decided to use brass plated pipe, steel strap, PVC pipe, and all-thread rod, fitted here and there with MDF covers shaped to impart a molded look and hide the ugly parts. If we start in the attic, there would be short length of 2 X 6 placed perpendicular across two rafters in the ceiling. Through the 2 X 6, a 1/4" all-thread rod would extend down vertically into the living space below, first passing through a solid column that would conceal it, and provide lateral stability. A length of 1" pipe would be fitted through a hole bored horizontally in the column extending out on both sides sufficiently so as to clear the enclosure. Inside the pipe, another length of 1/4" all-thread rod would traverse the entire length and extend out the ends where they would each pass through a steel strap. The main purpose of the horizontal all-thread rod is to hold the steel straps securely to the end of the horizontal pipe. The horizontal rod is held centered inside the pipe by a MDF disc drilled with a center hole, in each end. The steel straps extend down vertically to a point just below the speaker pivot points, on each side of the enclosure. Wood/metal (refers to the threads on either end) steel dowel installed on both sides of the enclosure extends through the steel straps.

The column was made from 2 1/2" PVC pipe (the drawing incorrectly specifies 4", 2 1/2" is correct) made solid by glued-in MDF discs. The two all-thread rods conflict with each other where they pass through the same location defined by the center lines of the column and the horizontal pipe. To resolve this problem, the horizontal rod was halved and each piece was welded to opposing ends of a short length of 3/4" wide steel strap. A 3/8" hole was drilled through the strap through which the vertical rod passes.

[Hearing Specialist]

Re: Tritrix HT Build with Ceiling Bracket Design

I think I honestly shed a small tear...

All those TriTrix enclosures...all that attention to detail...the crossover looks awesome...I think I need a hug...:D

[Soundslike]

Re: Tritrix HT Build with Ceiling Bracket Design

Once again, I guess I pressed the "Submit Reply" button before I was through....

Referring back to the crossover on a stool photo, notice that I've used black heat shrink to mark the negative side and red for the positive side. I used lamp cord mostly because it was available, and also by doing so, I could be sure the wire has sufficient capacity. I've yet to come across a good rule of thumb to use for selecting a wire gage when wiring drivers, or the crossover network. I'm sure there is guidance somewhere -- maybe someone can point in the right direction.

Before I move on, I wanted to recommend an inexpensive tool that's very handy for straightening out wires, something you often need to do when making a crossover network, if neatness matters that is. These are sheet metal bending pliers, available at, uh, Harbor Freight, for a song. I'd like to claim that I'm strictly a Snap On guy, but I'll readily admit that I buy more than a few things from there. Anyway, using the pliers - just insert the wire lengthwise and clamp gently, rotate, and repeat. In a later photo, I used these pliers to straighten out a driver frame.



In the next photo, I'm installing one of the crossover networks in a vented enclosure. I've chosen to attach the network near the vent, and on what will be the bottom panel, since the speaker will be used in the horizontal position, either as a surround or center channel. Note to self: Remember to cut away the insulation material in the area where the binding posts come through the back panel so you don't have to do it through the driver opening. That was a bit of a pain... I got the little LED light you see in use here at Ikea, and it's proven to be handy for tasks like this.




Here's the bent driver frame I mentioned.. And over in the background, you can see the finished speakers. This driver goes in the last one.



Using the wonder-pliers to straighten the frame... It worked fine; the patient has been returned to perfect health.



In the following photo, I'm using PE's speaker gasket tape, to provide a seal on the back side of the frame. The seal is necessary because the driver was made to be rear mounted with the gasket on the front edge. I've used locally available weather-stripping for this purpose, but I've yet to find a type that's as well suited as the PE product. I cut the tape at an angle, where the two ends meet, to increase the end surface area, and that should improve chances for a perfect seal.



In this last photo, I'm using a hole punch tool, called a revolving punch, to restore the hole the mounting screws will pass through. I suppose a drill could be used, but the results are going to be messy, and you run the risk of damaging the gasket to the point where you get a poor seal.

[Soundslike]

Re: Tritrix HT Build with Ceiling Bracket Design

The following photo gives a better view of the completed crossover with the leads attached. In this build, and a previous build of Tritrix TLs, I've opted to complete the enclosure construction and painting before installing the crossover networks. I've seen several builds where the builder either left one panel off for access to the interior of the enclosure, or the baffle or back panel was made removable. That seems unnecessarily complicated to me, when a proven, finalized, design is built and no revisions are anticipated. I suppose another reason for access panels is to make wiring easier, but I didn't find that task difficult with any of the Tritrix variants. You will have to make a wiring harness of sorts before inserting the crossover however.

[Soundslike]

Re: Tritrix HT Build with Ceiling Bracket Design

Referring back to the photo of the finished crossover, you'll notice that the leads from all components pass through the board. Connections are made on the underneath side, as mentioned earlier. Except for the terminal connectors, all components are secured with hot glue. Zip ties were added to the inductors, because of their weight, and because networks that are installed in the vented enclosures could end up either vertical or horizontal, depending on how some future owner chooses to use the speakers. The leads (wires) that pass through the board also serve to secure the components.

In the next photo, the underside of the board and the connections are shown. I made the connections using as much of the component leads as possible, rather than add wire simply for the sake of neatness. I wondered if adding wire would change any of the values because, at least in theory, added length and additional connections could add resistance. I rather doubt that any detectable difference would result, but why, I reasoned, take the chance just to make the underside look neater.

I followed the basic wiring rule that requires a good physical connection, before solder is applied. I think the logic is that the connection won't spring loose, in the unlikely event it get hot enough to melt the solder.

All of this spaghetti means that some provision must be made to make sure the wiring will not be in direct contact with the enclosure when the network is mounted. The green rectangles you see are double-sided tape, with the protective wrap still in place. Small pieces of 1/4" hardboard have been glued to the board to provide additional clearance, and the tape is stuck to the pieces. The unusual sizes and distribution of the mounting points were dictated by available space, or the lack thereof. Once pressed in place inside the enclosure, the board is firmly mounted and unlikely to come loose. If the board is to be mounted on the top or sides of the enclosure, I would recommend a more permanent method, since gravity will do its best to unstick the tape.

[Soundslike]

Re: Tritrix HT Build with Ceiling Bracket Design

Between the popularity of the TriTrix TL knock down kit and all the very well informed info here I'm wondering if it wouldn't be prudent to make this a sticky. I get the feeling the OP has quite a bit more up his sleeve yet for this thread and I can't help but think that even experienced speaker builders can benefit from the advice that is posted here.

I've seen "Stickys" but I'll have to admit I don't know what needs to be done to make that happen. You're right, I do have a lot more to post. I hope it's useful information.

[Soundslike]

Re: Tritrix HT Build with Ceiling Bracket Design

Using the measurements produced in the CAD drawing, I made this template, again out of 1/4" hardboard. It's the same as the actual boards I will make for the eight crossover networks I need. In the photo, I'm in the process of transferring the holes (where the component leads will pass through the board) to another board. I placed the template over the identically sized board and carefully drilled the first hole in one of the corners. To anchor one corner, and improve accuracy, I inserted a pin through through both. Next, I placed the board edgewise on the workbench which aligned the board with the template, and drilled a second hole through which a second pin was inserted. The purpose of the second pin is to keep board and template in the correct position relative to each other while the rest of the holes are drilled.



In this photo, I'm drilling through the template into the board below. I'm only marking the board with the drill, making a small dimple in the board where each hole goes. The actual drilling process was done with a drill press, several boards clamped together in order to speed up the process. Obviously, it isn't absolutely necessary to use a drill press, but it does avoid the occasional errant hole drilled at an angle. By the way, the reason I used the drill to mark the hole locations is that other methods you see on the bench, such as the nail and hammer, or the scratch awl, bounced things around too much.
As you can see in the photo, I didn't bother sanding the edges of the boards considering it to be "uncraftsmanlike," because after all, they're going inside the enclosure where they won't be seen. I probably will next time, if only to avoid posting a photo showing, gasp, rough edges.



In this next photo, you see a finished crossover network, with leads attached to the terminals.

[jcpahman77]

Re: Tritrix HT Build with Ceiling Bracket Design

Between the popularity of the TriTrix TL knock down kit and all the very well informed info here I'm wondering if it wouldn't be prudent to make this a sticky. I get the feeling the OP has quite a bit more up his sleeve yet for this thread and I can't help but think that even experienced speaker builders can benefit from the advice that is posted here.

[Soundslike]

Re: Tritrix HT Build with Ceiling Bracket Design

I'm interested in how your crossovers turned out, I have my parts, in waiting for payday to come around, so I can get started on them.

Thanks for the question -- here's more on the crossover networks (in the following posts).