# SDX15 mid Q sealed enclosure pics



## M4rk_23

I made it to CSS specs. I haven't finished the outside yet or plan to anytime soon so these pics are just to show the internal bracing.







Note the magnet fits snug to both side and rear braces. Also the rear brace I cut an opening to let the vent in the magnet breath easy.







Holes cut in misalignment to break up internal waves as much as possible.







Thoese big holes were cut with a 4 1/2" hole saw and had to be done on a bridgeport mill in low gear cause of the strain that big hole saw creates. 46 in total for 2 boxes it was a long night of fighting with pieces of plywood trying to be ripped from my hands.


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## Blaser

Welcome to the Shack Mark!

That's a great job you're doing!! :clap: What's the net volume of your enclosure? How will you power that beast?


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## M4rk_23

It's 3.4 ft^3 as per CSS plans for a sealed mid Q enclosure. The bracing design and all is from their plans the only difference is I cut holes instead of pockets with a router. Thanks for the welcome but I've been around here for quite some time I just read mostly ;-) I actually have 2 of these beasts left and right subs and there powered with a QSC PLX 3602 so each is getting about 1250w at 4 ohms. I use a Paradigm X30 for a preamp and a Behringer BFD 1124P for an EQ. They are running right up to xmax without the amp clips lights blinking at all so I got plenty of headspace. I'm plenty happy with my setup much thanks in part to you guys here and what I've gotten from reading on here and audioreview.com. I can't stress enough how valueable net forums are to me. I pretty much won't buy anything without doing research and asking around on forums first.


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## Blaser

With a box that size, I doubt the amp will be able to make the woofer move as much as Xmax on typical program material (even though modeling says Xmas at 20 Hz with 1250 W).:T

Any chance we can have a REW FR?


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## Mike P.

Nice work on the bracing, Mark. Are your subs strictly for home theater or are they for music too?


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## M4rk_23

Blaser said:


> With a box that size, I doubt the amp will be able to make the woofer move as much as Xmax on typical program material (even though modeling says Xmas at 20 Hz with 1250 W).:T
> 
> Any chance we can have a REW FR?


Ya I'm not really sure how to tell if I'm reaching xmax or how to measure it really. I wired one at 2ohms giving it 1800w and ran sweeps with them beside each other. There was not any noticeable difference in excursion visualy. I also pushed the one getting 1800w to see if I could get it to pop at all and it never did then it started getting warm to the touch on the dust cap and I stopped immediatly. I think I was playing a song that has a bass line that hits harder than anything in my collection and not sweeps when I was trying to get it to pop. Sweeps will make them pop in the lower Hz I think around 40Hz is where it does first then it dies back off 30hz and lower if I remember correctly. There was no equalization when I ran the sweeps. So I determined there wasn't a worth while gain in running at 1800w and that it was likely I would end up burning up a voice coil. I usually use that song to see what the max volume I can play a speaker at is. I turn it up till I get a little pop then back it off a couple. I actually haven't setup my BFD yet other projects take up my spare time right now so I don't have a graph to share yet.

My stereo is geared for music but it is hooked up with the TV. I have Paradigm Studio 100's V.2 for my mains it's a good sounding setup so far. :bigsmile:


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## Blaser

M4rk_23 said:


> I wired one at 2ohms giving it 1800w and ran sweeps with them beside each other. There was not any noticeable difference in excursion visualy. I also pushed the one getting 1800w to see if I could get it to pop at all and it never did then it started getting warm to the touch on the dust cap and I stopped immediatly.


Do never do that specially with sweeps (I suppose you're using sine waves). You can *EASILY* damage your voice coil or bottom out the driver. :raped::nono:

You can be glad your drivers are still surviving! I was speaking about typical listening material which is far less demanding that these kind of tests...


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## M4rk_23

Ya when I say pop it sounds worse than it probably is. What I actually do is get my ear right net to the cone and slowly and carefully turn up the gain untill I hear what I assume is the voicecoil bottoming. But I can just barely hear the slightest tick right next to the cone and as soon as I do I back off a few and leave it there. I do that with a loud song not sweeps just so I know how far I can push and so I don't do it unknowingly cause I wouldn't hear it from across the room. I've never blown a driver in this way it may not be the right way to find out just how far a driver will perform but it's worked so far. I would like to hear of a more technical better way to do this if someone could chime in. When I was pushing the one with 1800w with a song and couldn't get a tick out of it is when it got warm and I stopped. Yes with sine waves or sweeps I could hammer them to death I'm sure but I sure won't. So I now have them wired at 4ohms and run my amp right up to the clip lights with pretty much no fear of doing any hurt on them cause they sure won't pop before I get a red light. Again if I'm doing any wrong let me know cause so far they haven't had much play and I don't want to hurt them. Ok now I got more pics coming for you all thanks to Mike P for messaging me and asking. Just maybe not today got to get them uploaded and it's late or early I dunno pick.


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## M4rk_23

Ok here's the rest of my pics.

A few more from the inside...
















Just needs finished with some sanding, roundover the edges, black paint, and some spiked feet
















I made some aluminum spacers to make the socket caphead screws fit flush








I routered a pocket for the binding post plate to inset a little but not completely. It's kinda hard to see in this pic though.








Not bad work for a cnc machinist and a wooden boat building hobbiest :bigsmile:


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## M4rk_23

Oh and almost forgot here's my entire system


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## Ricci

Very nice set-up with the Studio 100's and all. 

"Amber is the color of your energy" " Woh...Ooohh!"

Nice poster too.


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## M4rk_23

That poster has been there for probably ten years :blink: It used to have black light on it made it glow but they had to go cause they vibrated to much. Imagine that :huh:

Oh and the subs actually sit back in the corners I just pulled them out for the pic. Someday I use REW and find out where they actually should go.


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## eyekode

Couple Q's:
How loud is your QSC amp's fan? Can you hear it from your seating position if the sound track is quiet? I.e. no background music and pauses in the dialog.

Have you tried stacking your subs as opposed to having one in each corner? When I had two subs I could not get good in room frequency response with them spaced out so far.


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## M4rk_23

The fan isn't to bad you can hear it if it's quiet but I'm also only about 8ft from it. I really mostly listen to just music and loud at that so I never hear the fan unless a song goes quiet after a hard bass section. Then you'll hear the fan cause it's on high but I also have a window airconditioner running so I'm not real concerned with ambient noise in my bedroom. I haven't really played around with the subs positioning yet there wired into L and R pre outs and not the sub out so I have them in stereo configuration. My room isn't very big and these subs are so big and pushing so much air I don't think it really matters if I find a sweet spot. Sure it will be better when I do and I'll probably wonder how I ever lived without it that way but too many projects for me right now to be worried with that right now. Sounds like a good winter project. :bigsmile:


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## kouack

Hello i'm building the same box, Did you put any stuffing inside like suggested? Santa should be here this week with my Xmas presents 2 SDX :jump:


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## gwil

How low do they play? i am building the same exact thing dual sdx15 sealed in 3.4ft^3, and would like to know they can hit low for those movies that demand it.


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