Bracing for TritrixMT

[ckmoore]

In doing probably a little too much research before starting my TritrixMT build, I saw some people talking about bracing for this particular design, but I did not see that mentioned on Curts site.

My first question, is does this particular design, (using 3/4 BB plywood in my case) need any internal bracing?

And, isn't bracing size very crucial since it will change the internal volume?

I understand the need for bracing, but it seems it must be calculated correctly as it will change the volume.

[[email protected]]

Re: Bracing for TritrixMT

does not his sight state that the size makes so its not nessasary?

[ckmoore]

Re: Bracing for TritrixMT

If it does, I did not see it listed on the build page.

Thats why I was a bit taken aback from other build articles talking about bracing..

[[email protected]]

Re: Bracing for TritrixMT

if your using 3/4 mdf i would sure you dont have to worry about it. if using 1/2 just use a couple of 3/4 dowles.

[rogoll]

Re: Bracing for TritrixMT

Look at the video PE did on YouTube illustrating how to assemble their kit. It will give you a good idea of what type of braces they used. Scroll down this page and take a look --> http://www.parts-express.com/pe/show...number=300-701

[lunchmoney]

Re: Bracing for TritrixMT

There are those who think bracing doesn't matter...

And then there are others (Wmax in particular), who feel that extensive bracing is absolutely critical for a speaker to sound its best... I've never heard a speaker braced to the extent that he goes, but he's got some solid-sounding theory (forgive the pun) to back it up... I'd love to hear one of his hernia-inducing designs someday.

I'm somewhere in the middle, and like to build my cab's with a fair amount of bracing... without a doubt I'd be bracing those speakers of yours.

So how do I conclude this? As well as it being sound theory that just plain makes sense...

The only thing close to a meaningful comparison I've ever heard is hearing my dad's unbraced BR-1's compared to my well-braced SR71's... of course they are very different speakers, but they do have nearly identical dimensions and internal volume... anyways, the BR-1's sound very resonant compared to the SR71's... you can hear the cabinets "singing along" in comparison.

So from this I've concluded with reasonable confidence that bracing is well worth it... here's how I braced the SR71's... relative to the entire build, it wasn't much work at all... so why not?

[waynew]

Re: Bracing for TritrixMT

Due to the size of the TriTrix MT, bracing is optional. If you are using 3/4" Baltic Birch, you will have plenty of stiffness. If you feel the urge to put alittle something something in there, go right ahead....but you don't have to. The pair that Curt and I made for the debut didn't have any bracing, but we did dip the MDF in possum snot (not to be confused with Wombat Urine!!!), and everyone knows that possum snot takes all vibrations out of cabinets. NASA started using possum snot on the hubble due to it's anti-vibration characteristics and have been very happy with the results. Curt and I will be selling Possum Snot in the near future...as soon as we can figure out how to collect it in large enough amounts. My idea is breed Possum's that have allergies...once we get a good brood that has a lot of Hay Fever, and Pollen allergies, we will then expose them to those allergens. We will toss a coin as to who extracts the snot from the kleenex tissues until a better collection system can be designed!

Regards,

Wayne

[lunchmoney]

Re: Bracing for TritrixMT

I'd be careful. I've heard that possum snot has a bad tendency to clog the kanooter valves.

[ckmoore]

Re: Bracing for TritrixMT

Got it.

3/4 BB... GTG
3/4 MDF... find a possum.

Oh, and everyone knows, possums use handkerchiefs, not Kleenex's.... come on... jeez.

[[email protected]]

Re: Bracing for TritrixMT

just build the box and thump it with your fist if it sings a little brace it if it does not, take it in the house:D

[curt_c]

Re: Bracing for TritrixMT

just build the box and thump it with your fist if it sings a little brace it if it does not, take it in the house:D

[brianpowers27]

Re: Bracing for TritrixMT

Personally I like the idea of a window brace about 1/3rd of the of way up going from front to back and side to side. Scoop out the driver cutout. I imagine that 3/8" ply wood be sufficient.

BTW: Doesn't 3/4" seem a little heavy for this small box? I imagine 1/2" with a brace should be very dead. You could even laminate 1/4"mdf to a 1/2" bb ply to achieve damping and stiffness.

[johnastockman]

Re: Bracing for TritrixMT

This is the TriTrix ported 2-way I made. About .25 ft3. I used a window-pane type brace between the woofer and tweeter so it ties the front, back and side walls together. In the right-hand pic, looking into the box from the front.



I've added bracing to many commercial speakers and subwoofers with good results, meaning a noticeable improvement. Especially commercial subs that typically don't have any bracing. Some doweling or pieces of scrap work well for internal braces. I use bracing on anything about .25 ft3 and larger.

John A.

[WmAx]

Re: Bracing for TritrixMT

Did you actually measure the wall responses with an accelerometer? I find it hard to believe the resonances are that high using conventional materials. More common, is to have panel resonances in the 150-250 Hz range with average bracing, or up to 600-700Hz with conventional 'heavy' bracing (which is still not really very effective bracing). I am assuming normal 3/4" MDF and the average 7-9" spans of bracing used by DIYers and 'high end' speaker makers.

-Chris

[WmAx]

Re: Bracing for TritrixMT

Personally I like the idea of a window brace about 1/3rd of the of way up going from front to back and side to side. Scoop out the driver cutout. I imagine that 3/8" ply wood be sufficient.

BTW: Doesn't 3/4" seem a little heavy for this small box? I imagine 1/2" with a brace should be very dead. You could even laminate 1/4"mdf to a 1/2" bb ply to achieve damping and stiffness.

Nah, here is a minimally acceptable box for a small 2 way bookshelf speaker(3/4 MDF external, 3/8" of visco-elastic dampening, 5/8" internal shell, solid oak matrix bracing, with no brace exceeding about 3" from any other brace point. Acoustical dampening is 6# high density rockwool fiber - far more effective than the common materials used - in effect zero reflected energy exists in this design over about 200Hz (and the small dimensions make issues under this band irrelevant)). Of course, I presume critical music playback is the priority. For background music or HT use - I don't believe this level of build is required - those are far less critical applications:



-Chris