Passive Radiator CSS SDX10 Design and Build

[EngineerNate]

I have had an SDX10 for ages that started life in my car. I haven't had a car system for ages so it's sat in my shop in a sealed car box for a long time. I finally have a little space for a system so I'm giving it a proper home.

After corresponding with Dan at CSS I decided on a dual passive Radiator design at 2.5cuft and 9 washers on the PRs, giving an F3 of 19hz.

I bought 4X of their closeout PRs and a second SDX10 so the first wouldn't be so lonely.

I used CAD to design the enclosure and take volume measurements. They will double as speaker stands, and are some point I'll make a third to help cancel out room modes.

The boxes are golden ratioed, because why not!

I have a few free days before Thanksgiving I'm hoping to use for assembly.

Cheers
Nate

 

[Curvature]

Nice driver and project.

https://audioxpress.com/article/test-bench-the-sdx10-home-audio-woofer-from-css-audio

 

[EngineerNate]

Nice driver and project.

https://audioxpress.com/article/test-bench-the-sdx10-home-audio-woofer-from-css-audio

I think several other subwoofer drivers probably equal it at this point for pure bass duty, but I already had one purchased back when XBL-2 was the new hotness, so the barrier to entry to getting another was lower than with another driver.

That said, it's ability to play cleanly very very high for a subbass driver opens up interesting possibilities for using higher crossover points to reduce distortion in my main speakers (since I can run the two in stereo and use them as speaker stands, eliminating issues with localization).

If I build a third sub, I may choose a larger driver or do a similar looking cabinet with two drivers in push pull, just to keep life interesting.

Once I've gone through a full build on these and verify the flat pack fitment, I will post step and DXF files for anyone who wants to build a copy.

 

[ThatSoundsGood]

Nice! My living room sub is a CSS 10" with dual PR's and I love it.

 

[EngineerNate]

Finally got my shop cleaned up and started assembly on these. Step 1 is to laminate the sides.

First, I align the side layers (in this case, a bottom) and clamp. Then using a drillmate and a sharp brad point bit, I drill for two locating pins:

By going in reverse first and letting the brad points score the surface, you can get an extremely clean hole:

Next, setup a vacuum bag, coat the mating surfaces with titebond II, put into vacuum bag and pull vacuum. Then check for leaks!

That’ll do. That’s about 3,763 pounds of force clamping the two together and to my makeshift granite plate, to make sure they stay flat during the layup.

Bagging materials are standard low loft poly fill to allow for air to escape, 6mm polyethylene sheet plastic, and butyl caulking tape. I bought the vacuum pot on Amazon, it acts as an accumulator and helps things pull down fast.

Now I just need to do this several more times. Once I get the process down I think I can do a couple at once, stacked up vertically in the bag with a sheet of poly between.

Cheers,
Nate

PS-mark your sides before you start rolling glue. Ask me how I know.

 

[EngineerNate]

Tops and bottoms laminated and ready for assembly. Backs next. I’m doing the panels you’ll see in-use most last so I learn as much as possible before doing the visible ones.

 

[Oddball]

Great project. And nice shop .

 

[EngineerNate]

Great project. And nice shop .

Thanks!

I spent my Christmas vacation cleaning and organizing it so I could actually do this project. It was a hot mess before, we did a massive renovation in the bonus room next door and my shop space got turned into a storage unit. A very dusty storage unit.

 

[EngineerNate]

All panels laminated, and the bracing is glued up.

I'll clean up the squeezeout and start corner chiseling things this week. This is the fun part.

 

[john61ct]

Different PR project, MBM focus

ISO passive radiator reco's for Mid-Bass coupler design

Noob here, what follows is from just reading, so please correct any misconceptions below, I realise I'm swimming deep way over my paygrade... This is not a trueSub use case, the point is bass reinforcement, using a single PR in the front to increase midbass SPL bandpassed well above 60Hz, maybe...

www.audiosciencereview.com

More context from the quotes here

Schiit Happened: The Story of the World's Most Improbable Start-Up

Ah, the infamous vertical Dual-Byggy-Stand :smirk:

www.head-fi.org

would appreciate any feedback, but please respond at the thread first linked

 

[EngineerNate]

Got all the corner chiseling done and the first pair of panels glued up today.

Going to buy more pipe clamps before I do another side.

 

[EngineerNate]

More progress tonight. I got the second side glue up done and got the PR holes cleaned up and back chamfered.