CSS SDX10 Ported Build Thread

**Owen Bartley** · **02-01-09, 10:32 PM**

I have finally been able to start my second sub build, and it is long overdue. First of all, I have to thank Sonny and the Shack, and Bob and Creative Sound Solutions for the driver, via this past summer's contest thread. I had some early plans, which I mostly stuck to, and the enclosure is a pretty standard ported 1.56 cubic ft., tuned to 24.5 Hz. It ends up with a 3" port, 17" long with a roundover at one end.

The amp I chose was the BASH 300, also from CSS, which I ordered when I won the SDX. I'll have some bracing built in when I see how the internals look, and it does use a double thick front baffle. It looks like this will share LFE duties with my old faithful Tempest, depending how they play together. Enough talk, here are some pics, and I'll keep updating as I go.

This is a very nicely built driver, with some good looking binding posts.

I almost missed the smell of MDF dust!

This is a pretty small sub, almost like a slightly larger, fatter tower PC case.

It's also packaged pretty tightly, but everything should fit well.

Front firing, and I'll have to do a decent job finishing it since I want it up front in the room.

I got as far as cutting out the amp mounting hole, and rounding over the inside edge.

I know it won't really do anything, but I want to round over all inside edges anyway. Makes me feel better.

More to come soon...

**Owen Bartley** · **02-01-09, 10:32 PM**

*** SPECIAL SIDE PROJECT ACTION ***

Since I wanted to do everything a little nicer, a little cleaner, and a little better this time around, I decided to do the driver cutouts with a router, using a jig, instead of hand cutting with a jigsaw and having ugly wavy lines. This necessitated the construction of the jig. thanks to some very informative posts here at the Shack, I think we were able to get off to a good start.

The jig is made from 1/4" plexiglass. Here it is taped to the original router piece for sizing.

Drilling the holes...

...and countersinking.

Test fit went well.

Out comes the centre hole...

And we taped a line...

...and marked out the measured locations where the pivot holes would be for standard 8" to 15" drivers (for mounting and flush mounting.

UPDATE: Here it is just about finished and ready to try some test cutouts

I'm pretty happy with how it turned out, and it worked quite well in the end.

**Mike P.** · **02-01-09, 10:57 PM**

Nice cabinet work.

What will you be setting the high pass filter to?

**Sonnie** · **02-01-09, 11:25 PM**

I have one of these that I may use in the great room after I move the Pulse out to the HT room. This will give me a good idea of something I can follow. I look forward to seeing the finished project and the results.

**Owen Bartley** · **02-02-09, 06:45 AM**

Thanks Mike. I actually somehow managed to mess up the length on the sides, which is why there's a 3/4" overlap in the pic with the amp. Then when I saw it, I contemplated leaving it as a "design feature" to help protect the connections at the back.

Based on this spec sheet, it seems to have 1db of boost from 25-30Hz, but I haven't been able to determine if there is a rumble filter or not. If that's true, I'll just leave it alone, but I'd rather not have it cutting any of the signal above tuning.

Sonnie, I'll keep you updated. It seems like you have your hands full with your next big project, which I'll be following too! This little guy's not quite in that league, but so far it seems like it will be a great small sub.

**Mike P.** · **02-02-09, 08:31 AM**

The Filter Fc is the frequency of the rumble filter. The default value is 17.7 hz.

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**Owen Bartley** · **02-02-09, 11:19 AM**

Either I was really sleepy when I was looking that up last night, or incredibly lazy. I'll probably just leave it at the default value, but now that I'm looking over it with fresh eyes, and comparing to the Win ISD model you made in my old thread, it might be pretty nice to have the 3 or 4db boost around 25Hz (green). Would that just wreak havoc on the excursion do you think, or would I be safe at reasonable listening levels with 300w? It's still technically above the designed tuning frequency.

**Mike P.** · **02-02-09, 02:19 PM**

With a 22.8 high pass filter and 3 db of boost you'll reach Xmax at 33 hz with 110 watts and have a large hump in the response. With a 20.4 HPF and 1 db of boost Xmax is reached at 33 hz with 300 watts, a much better choice.

**Owen Bartley** · **02-02-09, 03:02 PM**

Thanks Mike, I guess that makes my choice easy. It's amazing how thoroughly I've forgotten how to model a speaker and check parameters like that after a few months away from it. And I can always tweak the response with the BFD if I want to add a little more low end boost and tame earlier humps.

**Owen Bartley** · **02-03-09, 07:06 AM**

Small update today. I decided to order one of the flared port kits from CSS to compliment the CSS amp and driver, so I should have a 3FP kit coming soon.

Now I have to adjust the length for the flares on each end to keep my tune, but is there a formula for that, or a general rule of thumb? I was set on a 17" port without the flare.

**Mike P.** · **02-03-09, 11:23 AM**

A flared port 19 inches long would tune your box to 24.5 hz. The 17 inch port will tune the box to 25.9 hz. You can order a 2" extension piece and another connecting ring from CSS.

**Bent** · **02-03-09, 12:43 PM**

Owen, any chance you can confirm the cutout and heat sink plate measurments on the 300 watt BASH?

**jmuir** · **02-03-09, 01:19 PM**

Owen - Excellent work on the cabinet and circle cutting jig. Glad I clicked on it because I never would have taken into consideration the impact of the flared port on the tuning. If you like the 3/4 inch overlap of the side panels to the back panel, just say it was intended in the final design. People will never know the difference. I do like the fact that it kind of blocks the view of the amp terminals from the side. Cannot wait to see the finished sub.

John

**Owen Bartley** · **02-03-09, 04:22 PM**

Thanks Mike, I sent a quick email over to Bob at CSS, and if he catches it, I'll have a 19" tube (although that may not fit), otherwise I'll just extend it myself to a length that isn't too close to the rear wall.

Bent, off the top of my head it was exactly 6" x 10" measured, but you have some room inside that, and I think I ended up making it about 1/8" smaller in both dimensions. I'm not sure on the outside measurements of the plate, but I can check it for you tomorrow night when I'm home.

John, thank you! I may just leave them as-is, depending on how I decide to finish the sub and if it will make things difficult or not. I like your point about hiding the connections, I hadn't thought about that. Actually, I might even glue one on the top to match!

**Bent** · **02-03-09, 04:42 PM**

Thanks Owen, I'm toying with the idea of a SDX-10 and BASH 300 in the convoluted tube Idea I'm playing with on another thread.
I'd stand the amp on edge and install it into a cutout on the side of the tube - a challenging feat in-of-itself.

**Owen Bartley** · **02-03-09, 05:51 PM**

I'll have to check out your thread... I'd be interested to see another build with this driver! I know there are a few around somewhere. I would have liked to put it in a larger, lower tuned enclosure, but sometimes you just have a need for a reasonable sized sub (I know some would disagree with me

). I know I'll have more options for giving this li'l guy a good home.

**Owen Bartley** · **02-06-09, 11:24 PM**

Still plugging away a this when I have the time, and we made some more progress tonight. Finished the circle jig (updated above), and cut some holes. It worked pretty well, except at the point of entry, where it left a bit of a groove. It was a bit hard to get started.

First we measured out the mounting location. My original plan called for a centered mounting, but since the Precision Port I ordered flares from 3" to 6 1/4", I had to move it up and over a bit. I THINK I have enough room now... otherwise I'll work something around.

A test cut with the jig.

Here's the inner baffle

And the outer baffle. It fits quite snugly, but I don't think that should be a problem.

And the final baffle positioned together.

Still couldn't get perfect circles, although they're much better than cutting with a saw would have been. That's all for tonight, next time I'll probably set up the port, cut some braces for the side panels, and maybe get started with assembly. I'm still thinking about finish options, but it will probably be pretty simple.

**Bent** · **02-06-09, 11:53 PM**

Owen, it looks like your router might be wandering a tad - not a lot though.
it's either the pivot pin or the router base.

What size hole is required for the port?

I used a hole saw and a vacuum to do a few holes for port flares (they happened to be the right size) in 3/4" mdf.
the vacuum would pull the dust out before it could clog the teeth and build up too much heat. Also, if you turn piece over you'll avoid tearing the far side of the hole.

**Owen Bartley** · **02-07-09, 12:22 AM**

Yeah, being my first attempt, I'm sure I wiggled it a little bit. I think next time I'll cut 9/10ths of the hole and then go back over the rest of it once or twice quickly to clean up any bumps, and then finish the cut.

I'm not sure what size the cutout is for this flare, but that's exactly what I did for the cutout in the plexiglass jig, so if I can use it here it would be great. Thanks for the tip.

**ISLAND1000** · **02-07-09, 12:56 AM**

Hey Owen,
What do we know about the frequency response of the SDX10 above 40hz? I'm trying to put a 2 or 3 way together for mains starting with a 10" like the SDX10? Looking for ultra-smooth that'll play at 110db.

**Owen Bartley** · **02-07-09, 09:44 AM**

Hey Phil, I really have no idea how this driver performs in the upper range, and I couldn't find much when looking around either. I did find one thread about the SDX10 vs SDX7 in a tower speaker, and it sounds like they were leaning towards the 7, or dual 7s.

The official PDF isn't much help, and all I know otherwise are the T/S Parameters:

Fs: 26 Hz
Qes: 0.47
Qms: 4.0
Qts: 0.42
Vas: 53 L
Re: 3.5 Ohms
Xmax: 18.4mm
Sd: 300 cm^2
Le: 1.42 mH
BL: 11.8 Tm
Mms: 112 g
Pe: 300 W

I don't think this driver would have the finesse for a 2 way design, but maybe it could work well as a woofer in a 3 way. I'll look around a bit and let you know if I can find anything else, and if you do, shoot me a link. I'd be interested to see it.

**ISLAND1000** · **02-07-09, 02:34 PM**

OK, I'll keep an eye peeled for info.
I like your box dimensions and the port placement, I guess you'd call it "classical" shape and placement.
Did you find the plexiglass (see through) an advantage when using the router?

**Owen Bartley** · **02-08-09, 07:52 PM**

Thanks Phil. I wanted something a little easy on the eyes with this project. I really wanted to do a curved top, but couldn't figure out a practical way to do it, and I really wanted to get going, so I stuck with a pretty standard box shape. It will be interesting to see how the Precision Port fits in (I'm anticipating I might have to trim the port flare a little), but it should be pretty enough to have in the front stage without cringing.

**Owen Bartley** · **02-11-09, 09:52 PM**

Haven't had time to get anything done lately, but I have looked at it with my newly arrived precision port, and now I have some more port questions (Mike P., these may be for you). The port lengths I have to work with are as follows:

- centre tube: 17"
- centre tube and front flare: 20"
- centre tube and both flares: 23"

The length I have available for the port from the outside front baffle where it will be mounted to the INSIDE rear wall is 19 3/4". This is even after I add 3/4" with a new top and bottom to fill in the 'lip' I was left with (described in post #5). The original design used a straight 17" port, with no flare, just rounded over at one end. Right now I'm thinking about just using the flare at the front of the box, and cutting the centre tube to about 14", giving me a total length, including flare, of 17". I know it puts me closer than ideal to the rear wall, and I only have 2" of clearance when I should have at least 3", but I really want to keep the tuning as low as possible. Would this be a tragic mistake? Would it be tuned somewhere around 25Hz?

**Bent** · **02-11-09, 10:56 PM**

Owen, I realize your port is going to be offset w.r.t. the driver, but is there any chance you can add a re-base to gain an additional 3/4" for rear port spacing ala Thomas' W's AS-15 Klone?

My version (which I never did veneer, is a little more visible)

this effectively moved the port flare forward 3/4 inches to gain me the same in clearance behind the inside flare.

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