Tritrix TL build photos

[john trials]

I'm just about finished with my Tritrix TL build, so i thought I'd post some photos of the build. First, obviously, thanks to Curt for providing such nice and complete build information. Thanks also to my generous neighbor with the minivan (MDF trips)...I'd never have been able to do this without his help. Also to my dad, who loaned me a router, which also had a circle cutting jig. I think I'm the last one to use this router, about 25 years ago to make a 6' tall stereo cabinet. The circle jig had never been used!

My cabinet design keeps the acoustic path the same as Curt's original TL design, but I added 1 foot to the height (underneath). This raises the tweeter to ear level. The enclosed space under the TL holds some sand for stability (as if lugging these around isn't hard enough without an extra 15 pounds!). The bottom chamber holds the crossover, and is open at the bottom. This allows great access to the crossover. The bottom braces have T-nuts in them, to allow various finishing touches to the bottom. I originally planned on a solid plinth (which I've built), but I've decided to make aluminum outriggers with spikes (I have access to a milling machine).

Since I live in the real world, I'm adding grills. A neighbor came over while I was first listening to the clamped-together speakers and he tried to poke his finger into the woofer. I guess if something is out in the open, someones going to poke at it! I thought kids would be the problem, not adults. I've finished the grill frames, so I just have to apply the fabric.

Finishing was done with latex primer and paint, applied with a roller (to keep with the low-budget aspect of this speaker)...just like finishing off the living room walls. Simple, and it gave a very nice textured finish. A lot easier than spray cans, and a lot cheaper. I used satin black paint. I originally wanted to paint them bright red, to make them stand out in the room, but the WAF changed that decision. I don't regret it. The black looks nice.

[john trials]

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[john trials]

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[brianpowers27]

Finishing was done with latex primer and paint, applied with a roller (to keep with the low-budget aspect of this speaker)...just like finishing off the living room walls. Simple, and it gave a very nice textured finish. A lot easier than spray cans, and a lot cheaper. I used satin black paint.

I did one this way and I am happy with the way it turned out. I find that latex is very fragile... Due to the nature of the paint I used a low sheen topcoat. It is a lot more durable now.

[john trials]

I'm trying to think of tips to help other new builders (this is my first build...Statements are next!).

Make as many cuts oversized, then use a flush trim routing bit. This saves tons of sanding time, and your panels don't have to align perfectly. Of course, on a lot of boards, accurate cuts will save you a lot of pain later on. Spend a lot of time making really accurate cuts. My shop is very limited, so I had to use a hand held circular saw with a saw board.

In one of the photos, you can see some Harbor Freight pistol-grip clamps. These hold things, but their clamping power is WEAK. Go with a better brand (Irwin, etc.) for pistol-grip clamps. Screw-type clamps are MUCH better for glue joints. I found that Harbor Freight screw clamps worked as well as some borrowed Jorgensens. The Jorgensens were definitely better, though.

[john trials]

I forgot to mention using Seal Coat wax free shellac prior to priming. I coated the inside of the cabinet with one coat, and the outside with two coats. Gotta seal the MDF before paint!

[lunchmoney]

Looks solid, well-braced, nice paint job.

Nice work!

[john trials]

Thanks Lunchmoney. I have to add that your builds have been a major inspiration to me making these Tritrix speakers. I love looking at your build photos. I drooled over them for quite a while. Once PE put the Tritrix parts on sale, I immediately got out the credit card.

[jerryanderson]

Your Tri's look really nice, great work. I bet they are fun to move around! Your right on stray fingers....adults do tend to be worse then kids. Dome Tweeters seem to be a strong magnet for poking fingers!

[john trials]

Another tip for beginners: To help with 90 degree joints, use 90 degree clamps (Lunchmoney's build thread shows some good ones) or anything with a reliable 90 degree angle. I clamped some precision 90 degree aluminum trusses used in optical assemblies (overkill) that I had in my basement.

Pistol grip clamps hold things together, but the screw clamps provide the real clamping.

http://techtalk.parts-express.com/attachment.php?attachmentid=8037&d=1270737902

[lunchmoney]

right angle clamps... $9 at home depot... note one on each side... they work great

http://i249.photobucket.com/albums/gg210/djnelsen1/SR71_A.jpg

[gumert]

Great looking build. They look like the came together a lot nicer than my current statement build. Then again, this is only my third build and my first not that rushed build.

Good work.

[johngalt47]

Are you satisfied with the way they sound?

[john trials]

I really like the way these Tritrix TLs sound. I am very pleased with the results. I highly doubt any $200 store-bought speaker would come close to the quality of the Tritrix.

But for me, it wasn't about making speakers that beat the manufacturers. I mainly made the Tritrix to see if I could make nice cabinets with the very limited tools that I own (and borrowed)...a true budget build. I also wanted to see if I enjoyed making them (I did) before going on to something big. I was looking for a fun project that would be useful when I was done...building speakers seemed like a good choice (and it's a lot less expensive than a project like restoring a car).

I cannot make critical comments, though. My only reference is a pair of 26 year old AR45s (a 3-way with 10" woofer) with new surrounds on the woofers. I like the Tritrix better than the AR45s (anyone want some AR45s?). I do not have a lot of listening time on various speakers.

My next project is a pair of Statements. After they are finished, I'll hopefully gain some knowledge into fine sounding speakers and be able to comment more on the qualities of different loudspeakers.

[johnastockman]

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Wow, nice work! As a former long-term employee of a local high-end audio store, SQ was the main reason I got into DIY...not mainly to save money, but because with all the mid & uber-priced speakers I've heard and sold, it was a listening experience with some Speakerlab DIY designs that convinced me you could get better SQ for less money. Besides, what I saw and heard with some of the high-end speaker companies was, well, not what you'd expect for the high price tag. I built a pair of Curt's TriTrix ported 2-ways in a .25 ft3 cabinet and they trounce similar offerings from the retail market that cost 3-4 times what I have into the TriTrix's...even with some factored in for my time. The Statements are on my short list for a nice higher-end DIY design...the designs I've built have been more budget-oriented, but the SQ belies the modest amount of time & money I have in them. Again, very nice work! I look forward to seeing the Statements come together.

John A.

[john trials]

johnastockman, thanks for the nice compliments. I wish I had a wider knowledge of different speakers, like you. I'm thinking sometime I may mess with the crossover on the Tritrix just to see the effects on the sound, and gain some knowledge into different filters. I'm sure if I design my own loudspeakers, I'll learn a bunch!

Don't hold your breath waiting to see my Statements! I am amazed at how little free time I have now. I have everything necessary to build them (except veneer). Realistically, I hope to have them done by the end of August. I'll post a build thread over on HTGuide later in the summer.

[Rightbrained]

Nice work John !
The Statement project you are planning next will be a lot of fun . The project will require a lot more work but ,trust me , you will not be disappointed at all.

[john trials]

I have a hand truck, which will be good for moving the Statements from the basement to the garage (I could carefully carry the Tritrixes...but what a pain...many trips up and down...and a big risk of putting a ding in them). I do the gluing and finishing in the basement, and the routing and sanding outside.

I do need to make some saw horses before I can work on the Statements.

[john trials]

I machined some simple outriggers from scrap 1/2" thick aluminum. A bit of sanding and Scothbrite make the scrap aluminum look pretty good. Nothing fancy, as the mill I have access to is a 1942 Bridgeport...no CNC.

The hex head mounting screws will be replaced with socket head cap screws which will be hidden by the machined counterbores...not that they can be seen unless you're laying on the floor!

The spikes are just 1/4-20 threaded studs with sharpened ends.

My ears are not sensitive enough to know if this made a change...for me it's purely cosmetic.

http://www.observedtrials.net/otn4/outriggers small.jpg



ADDED: Curt's thoughts on stuffing the Tritrixes


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There are at least 3 factors at work here on finding the optimum stuffing the TriTrix, or any TL enclosure. An unstuffed line will exhibit strong enclosure resonance at multiple frequencies above the tuning frequency due to the standing waves and acoustic impedance of the line. Stuffing the line ameliorates these issues, and smoothes the response. However, too much of a good thing (stuffing) also has the effect of damping the output of the terminus. Fortunately for us, typical stuffing materials do not damp the lower frequencies as much as the higher ones, so to a certain extent we can have the best of both worlds. Hence axiom one for stuffing:

1) Stuff the line until the bass output of the terminus just starts to be attenuated. -Use this as a starting point and adjust your stuffing from there.

The position of the stuffing and the density of the stuffing has a bearing on the damping level with respect to frequency. In general, the last 1/4th to 1/3rd of the line should be left open. Adding stuffing here will attenuate the terminus output, and ultimately turn it from a TL enclosure to an aperiodically damped sealed enclosure. In general, more dense stuffing from the driver end of the line down to the middle of the line, tapering to less dense from that point, will provide better damping and terminus output than a lighter, but linear stuffing density.
Axiom two:

2) Start with a light equal density stuffing, and if necessary add additional stuffing to the middle and closed end of the design. (Leaving room behind the drivers for them to breathe, of course.)

Room modes, and speaker position in the room will affect the perceived bass response at the listening position. If the speakers are required to be somewhat closer to the front wall than normal, extra stuffing can help attenuate the ‘excess’ bass from the additional room loading. In other words you can to a certain extent tune the bass response to your particular room requirements.

3) Do your listening evaluations with the speakers in their intended listening positions in the room.

Stuffing a TL is like putting chocolate syrup on your ice cream. It’s not rocket science, so don’t get carried away worrying about linear stuffing density or weighing each handful of stuffing. Start out with 2 equal piles of stuffing. Use the TLAR method to determine the initial amount to add to each enclosure. Listen to the result. If changes are necessary, add /remove/reposition a handful or two at a time in each enclosure to keep things relatively equal. You will be working through the driver holes, so some creativity may be required to obtain the stuffing placement you desire.

The bass response will come up as the drivers break in. A few hours playing music through them at reasonable levels should be close, but they may continue to loosen up a bit more with time. Hence, amiom four:

4) Allow time for the drivers to break in before making your final stuffing adjustments.

Listen to a variety of music. Like voicing, it has to sound good over many different genre, and certainly the bass output varies significantly from artist to artist.

C
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[AudioMixer]

Hi John, from a new comer to this cool forum - I don't mean to ask a silly question here but is this the same kit from PE?
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-701&FTR=300-701&CFID=10106761&CFTOKEN=72523349

:)

[johnastockman]

Hi John, from a new comer to this cool forum - I don't mean to ask a silly question here but is this the same kit from PE?
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-701&FTR=300-701&CFID=10106761&CFTOKEN=72523349

:)

Yup, that's the same design. John built his own enclosures, but those PE knocked-down cabinets are a really good deal. Same TL and bracing, though.

John A.

[john trials]

The kit I got was the 300-700 (drivers and crossover parts) which is a great deal, when you consider that originally, the parts were $170 total. I built my own cabinet.

[krillen09]

Speakers look great. I think my next attempt at Tritrix TLs may look remarkably similar to this...

[john trials]

Thanks for the compliment.

It's been a few months since these were finished, and I still really like them (even though I now have Statements on my nicer stereo system). The only change that is not in any of these Tritrix build photos was the grills (front and back). Black grill cloth on black enclosures...it looks really nice.

The only thing I'm not pleased with is some subtle shifts in the glue joints that are showing through the paint if I look really closely in the right light. I'm going to veneer my Statements (they are bare MDF right now), but I'm going to use them for a month or two before I veneer them, so hopefully the glue joints will settle in that time.

[lunchmoney]

The only thing I'm not pleased with is some subtle shifts in the glue joints that are showing through the paint if I look really closely in the right light. I'm going to veneer my Statements (they are bare MDF right now), but I'm going to use them for a month or two before I veneer them, so hopefully the glue joints will settle in that time.

That's the nature of mdf. It expands and contracts slightly. Short of veneering, I doubt there's any way to completely eliminate this from happening. A thorough sealing of the mdf prior to painting helps a lot, but still doesn't eliminate it completely.

[john trials]

Yeah, I did seal these inside and out prior to painting (2 coats of Seal Coat).

I was thinking of taking them apart, resanding, then repainting, but I really hate the 'finishing' part of any project (I'm a perfectionist, but I know I cannot achieve a finish that meets my desires!). If it works (sounds) fine, then that's what I really care about. I'm going to leave them as-is.

[fish-24_7]

It is tricky. I know you used Seal Coat. Have you ever tried different sealants? I wonder if you could have gotten better results with, say for example, 60/40 wood glue & water?

[arlis_1957@yahoo.com]

yeah, thats the one. he just made them taller with a false bottom.

john, those out riggers are pretty nice. similar to mine.

[john trials]

It is tricky. I know you used Seal Coat. Have you ever tried different sealants? I wonder if you could have gotten better results with, say for example, 60/40 wood glue & water?

I've never tried other methods of sealing the MDF. This was my first build. I don't think a change in sealant will affect the shifting of the glue joints, though...but that's just an intuitive feeling. I think the stresses in the glue joints take time to settle out. Although I'm not sure if what I'm seeing is due to MDF expanding and contracting with a change in moisture content or if it's due to the relieving of stress in the glue joints.

With my Statements (which is my 2nd build), I'm going to listen to them for about a month or two before veneering. There is no sealant on the outside faces (the inside has 1 coat of Seal Coat). When I decide to veneer, I'll sand the outer faces, then put on one or two coats of glue, and do the iron-on method for attaching the veneer...hopefully the joints won't show through!

[john trials]

yeah, thats the one. he just made them taller with a false bottom.

john, those out riggers are pretty nice. similar to mine.

Thanks for the compliment. Those outriggers were fairly simple. I wish I had access to a CNC machine so I could really do something creative. If you like those outriggers, stay tuned...I've got some massive outriggers for my Statements (which weigh over 120 pounds each...the Statements, not the outriggers!), but I will not reveal them until I veneer them in a month or two (over at HTGuide). I'm also thinking of asking my father-in-law (a blacksmith) if he could make some claws, which would make cool outriggers...although that might be more work than he's willing to do.

[kevinr]

"That's the nature of mdf. It expands and contracts slightly. Short of veneering, I doubt there's any way to completely eliminate this from happening. A thorough sealing of the mdf prior to painting helps a lot, but still doesn't eliminate it completely."

Does Baltic Birch Plywood share this same issue in building ?

[arlis_1957@yahoo.com]

i think the trick is to put the "end grain" where it is not visible once placed in their home. if they are to be painted, seal, use lots of primer on the end grain, and then paint.