# CSS SDX10 PR Tuning



## halesway (Jan 4, 2009)

So started with the kit and all is well. Actually got two, one for me and one for a buddy. 

Well here goes - I've got a little issue with the box I built as my buddy who picked up the other kit, re-mapped the cut list based on the fact that we stumbled into some sweet 2' x 3', one inch (wait an important detail comes later) MDF cut-offs at a local finishing carpentry shop for $2 a piece.

My buddy emails me the new CAD drawing of the cut list from the 18" cube plan (compensating for 1in material) from CSS which has been built on here many times before (all which look 'very nice'). 

I grab cut sheet, start blasting out the panels, make a router jig, practice cutting holes on some leftovers, dial in the jig, build a dust table for the router and 'job-mate' work bench.....take the 18.5 inch square front piece, make my cuts for both boxes and I'm off to assembly.

I begin the assembly...um something's not working. Wait a minute, I double check my material measures and everything lines up...matches my cut sheet and then I realize...and almost cry, the material is 1 1/4 inch thick MDF. What. Someone made a poor assumption (thickness from guy at shop wihtout checking and making new drawings), and some idiot cut all the panels without checking - there, I'm sharing the blame equally with my buddy.

So needless to say I assemble 1 of the boxes yesterday, but at some point I'll have to figure out how the 'diminished' volume effects the tune. Doing some quick math in my head (without the box anywhere near me) the interior measure is now 16 inches x 16.25 inches x 16, 2.41 cubic ft or 68.25L.

That being said, I'm a total noob at building or designing a sub box. I used the kit to get my feet wet and based on the amount of proven builds on this forum.

So I need a) help figuring out where to go from here.
b) how to tune the two PR's on said box.
c) advice on bracing, thus far with one side still open I can add bracing but this is 1 1/4 inch MDF.

Ok - let me have it. Any feedback is appreciated. If I grow some, I'll post pics, but glue, screws and clamps on a first time box sure isn't very purdy. Another quick question (after using the cut-offs, and them not being 'square') I've got some 16th of an inch tolerance issues....I'm guess nothing that a little silicon, wood/body filler and sanding won't take care of?

On happy note I bought/ordered PSB Imagine T's, a C and S's all in Cherry to finish off the theater room I've been playing with for the last 12 months.

Thanks fellas....feed back and advice welcome.


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## Mike P. (Apr 6, 2007)

> Doing some quick math in my head (without the box anywhere near me) the interior measure is now 16 inches x 16.25 inches x 16, 2.41 cubic ft or 68.25L.


Verify the internal volume and we'll figure out the tuning.



> advice on bracing, thus far with one side still open I can add bracing but this is 1 1/4 inch MDF.


No bracing required with that thickness, the panels are strong enough.


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## halesway (Jan 4, 2009)

Mike P. said:


> Verify the internal volume and we'll figure out the tuning.
> 
> No bracing required with that thickness, the panels are strong enough.
> 
> ...


measurements confirmed +/- a 16th.

16x16x16.5 internal volume.

Cheers


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## Mike P. (Apr 6, 2007)

There's only a few liters difference in volume between your thicker paneled no bracing box and the kit plans. Adding 6 washers per PR ends up with the same frequency response and output as the kit.

View attachment 25926


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## halesway (Jan 4, 2009)

Mike P. said:


> There's only a few liters difference in volume between your thicker paneled no bracing box and the kit plans. Adding 6 washers per PR ends up with the same frequency response and output as the kit.
> 
> View attachment 25926


Thanks for plotting that Mike. Much appreciated. Now time to try and get this thing up and running by the 10th as our daughter is having her 6th Bday party in the uncompleted as of today theater......

The next 10 evenings (afterwork) are going to be busy finishing trim and finishing the wire runs and completing the install in my modest theater room.


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## Mike P. (Apr 6, 2007)

Post some pics of the build progress, we'd love to see it.


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## halesway (Jan 4, 2009)

I'm acutally a bit embarrased by me lack of carpentry skils, but I may snap a quick pick after first coat of 'filler'...haha. My box is no where near as nice as any on here. I have some aspirations to get better, but we'll see how it turns out.


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## halesway (Jan 4, 2009)

So I've got this box going and have filled, sanded, filled and sanded then primed, filled, sanded and primed again. Didn't turn out awful for my first box. I'm not sure yet if I'm regretting not grabbing the router and a round-over bit and 'softening' the look some, but I could always do that on a second box. I snapped a pic on my phone after my first coat of primer, sealer and I'll see if I can get it on here. This working in an unheated garage in Alberta is a drag, and then having to haul it into the house to 'fill and spray' is getting tedious.

Last night I grabbed the weigh scale and dropped the box on. Without any 'hardware' or the PR's, sub or AMP, just the MDF, this thing weighs 52.8 lbs. For an empty box. 

Tonight I'll spray a coat or two of flat black (want it to hide in the darkness of my theater room) and see how it looks. 

Question about hurricane nuts....I've read a number of different ways of using. I read guys who've 'drawn' them in with the bolt. I've read of guys 'hammering' them in, and I've also read of guys using a 'c-clamp' to squish them in? Thoughts - cus I haven't done it yet. I'm also a bit nervous (because I haven't measured) wether the hardware is long enough due to the thinkness of my MDF, but I'll check that tonight.


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## Mike P. (Apr 6, 2007)

Which ever way you would feel more comfortable doing all three ways will work. And we still want a pic!


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## halesway (Jan 4, 2009)

Yeh the install of the huricanes sucked.
SHould have done them early and left them until late.

I probably had three on each strip out of th MDF. Just got the PR's and driver installed last night.

Plugged in and well it's ok. I realize now an 18inch cube on my front stage of my theater room is too big. So this box will make due until spring (tired of trying to moderately heat the garage, then carrying box back in house to glue, screw and fill) and I'll build this brute into a 'end-table' type of configuration.

Wondering about the SDX7 as they would look appealing on the front...then having the 'end-table' mid room between my two chairs in my front row.

I how have 4 embarrasing pictures on my phone of this build and once I figure out how to post/host and resize them I'll put them up.

Along with that I'll shoot up a pic of my almost completed theater room with my new PSB Imagines.
Cheers


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## halesway (Jan 4, 2009)

Oh forgot to mention I acquired an Anthem MCA20 with which I could power a couple of SDX7 'mid-subs' for front fill....oh to dream.


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## Mike P. (Apr 6, 2007)

The SDX7 isn't much for low end, 1 cu.ft. tuned to 30 hz would be the best it could do. 100 watts with a HPF at 27 hz would be maximum. 100 db at 30 hz would be it and then it drops like a stone.


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