# CSS SDX10 - Best alignments?



## Owen Bartley

I was just wondering what those of you who have bought these subs (and those who are hoping to win one  ) have done with them, and I couldn't seem to find any build or design threads. 

I'm thinking the recommended ported alignment of about 1.5 cubes may work nicely for a little guy, and could be a great project sub for me to work on with a friend who insists he doesn't need a sub, although he badly does. I think I could convince him to find room for a small one, but I don't think the sealed version with an F3 of 44Hz will impress him enough, or deliver enough beyond what his Paradigm Phantom towers already do. 

Any firsthand experience with either one? Recommendations for an 80/20 HT/music setup where size is a constraint, and low is more important than loud?

E: Hmmm... after doing some thinking and sketching, I think a 12w x 15h x 20d should be able to fit the driver and 3 x 17" port on the face, and gives about 1.77 cubes internal (with 3/4" MDF) before driver and port. That would leave me a little bit shy of the 1.5 needed, so maybe bumping the depth would give the port some more room to breathe, and give me the required internal net volume.

E2: Looks like 13 x 16 x 22 gives me a net volume of about 1.58 cubes, assuming the driver takes up about .12cf. I have a feeling this will be pretty close to the size limit this guy would be willing to accept, so I may have to look more closely at the sealed alignment, although it wouldn't be my first choice.


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## eyekode

I have been thinking about this too .
I think the options are:
1) a sealed music sub
2) small ~1.7ft^3 tuned to ~28 hz (4" port ~22", would require a bend and it is questionable if it you could fit it anyway ).
3) ~4-5 ft^3 low tuned. This might sound silly but it models pretty good with some eq if you don't have huge SPL requirements. It is good for ~103db at 20hz with only 200w!


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## Owen Bartley

wow, eyekode, that's a big "little" sub! lol But hey, I guess you can't argue with results. Unfortunately, if I do end up working on this project for a friend, he doesn't want anything big, so I'll have to stick to a limit of about 1.5 cubes (internal net volume) on the high end. What about tuning that version lower? I believe the posted recommended ported alignment had a 3" flared port 17" long, and tuned to about 24Hz. Would a tune closer to 20Hz help the response do you think?


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## eyekode

hrm... my problem with the recommended alignments is the 3" port. The air velocity will be pretty high. But dropping the tune in such a small cabinet does not seem to help. The frequency response actually rolls off faster. Need more volume for an EBS-like alignment. I actually liked tuned a little higher with a 4" port.

I think the only real problem with any of these setups is how quickly you will hit Xmax! 50w at 10Hz does it. To make it fool proof will require a high pass filter.

And yes a 4-5ft^3 enclosure for a 10" driver is silly .


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## Owen Bartley

It's not silly if it sounds good! 

You're right about the high pass, that would be a good idea on a driver like this. I guess I could look into a plate amp that has something built in, but I can't remember offhand who (if anyone) offers one like that these days. Research time!

Edit: I think I'm still liking the small-ish ported box and I mocked up a quick design:










The BASH 300w amp from CSS looks like a good match for this driver, plus they ship cheap in Canada.


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## mgboy

IMO - with small drivers like that ported is almost a must due to the low displacement (yes, even with nearly 20 mm of xmax) but I sure do love the look of small sealed cubes with little subwoofers. 

2.4 cubes tuned to 20ish Hz with two heavily flared 2" ports? I was modeling it earlier and IIRC something like that sounded good, I'd have to check again.


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## Owen Bartley

Mike, I know what you mean, this would look great in a small sealed cube, I just don't think it would hit hard enough on the low frequencies. The size would be perfect for my buddy, but too bad! If I'm building this thing for him, I'm going to get him a bit closer to a "proper" sub with better low end extension... but I will keep his sensitivity to size in mind, so this is kind of a best of both worlds design.


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## Owen Bartley

Well, thanks to Sonnie, the Shack, and CSS, it looks like I'll have one of these bad boys coming to me. I am still fairly set on this ~1.5 cube ported box, I just wanted to check to see if anyone thought the 300w BASH amp from CSS would be a poor match for any reason. I know it doesn't have a subsonic filter, but I'm not hugely worried about that if it is set up carefully. I could step up to the 500w if there would be a reasonable improvement, but if it isn't necessary, then I'll stick with the 300w. I'd also like to give CSS my business since they generously provided the sub for the Shack contest.

E: After doing some reading, I've seen a few mentions of the BASH 300 using a HPF at around 20Hz, which I'd be OK with, but someone also said (maybe just early versions) had it at 30Hz, which I'd want to change.


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## Owen Bartley

I received my SDX10 and BASH300 today, and I'm pumped to start this project. I don't know when I'll actually get to begin, due to a backlog of a few other projects, but man is this going to be a sweet little sub. The SDX is really solid and heavy and appears to be built like a little tank. I have a good feeling about this one.


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## BoomieMCT

Just out of curiousity - did you model this design in WinISD or Unibox?


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## mgboy

I haven't gotten mine yet - hopefully it'll arrive next week. Good luck on the build.


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## Owen Bartley

BoomieMCT said:


> Just out of curiousity - did you model this design in WinISD or Unibox?


Aaahhhh.... well, actually, I haven't modeled it yet. :dunno:

I have both around somewhere, and I know I SHOULD, but I was going off the manufacturer's recommended design. I'm still a while away from cutting any MDF, so when I get a little more time I'll probably model it in one of them, just to get an idea of what it looks like, and if there are any little tweaks I can make.


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## BoomieMCT

Owen Bartley said:


> Aaahhhh.... well, actually, I haven't modeled it yet. :dunno:


Two demerits! :devil:

Many good manufacturer's designs work well but it is always good to double check and make sure its going to do what you want. Also this will answer questions about port size, port airspeed, etc. blah blah blah. ALSO it is good before you buy to compare products.


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## Owen Bartley

lol... OK, OK, you caught me. I've been revising the look of the box anyway, so I will model this puppy out before deciding on final dimensions and porting. There wasn't much competition for the driver since I won it in the last Shack contest, but boy was I impressed with it when it arrived. I did want to experiment to see if I could tune it a little lower than the manufacturer spec box, so once work and a few previously started projects get out of the way, I'll input some numbers.


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## Ricci

Try modeling this one. 
2.7ft vented 
19hz tune
4" x 31" port (bend it)
Bash 300 amp.

I think it looks great. Should have solid output down to 17hz and be amp limited from there on up too. Kind of like an SVS PB10.


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## mgboy

I like the looks of 2.5 tuned to ~21


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## Mike P.

Got my curiosity going so I did some modeling for this sub:

Green - recommended ported application - 1.5 cu.ft. tuned to 24.5hz
Yellow - recommended sealed application (volume adjusted to achieve a Qtc of .7) 
Pink - Josh's suggestion - 2.7 cu.ft. tuned to 19hz
Blue - Mike's suggestion - 2.5 cu.ft. tuned to 21hz.

All four alignments handle 300 watts. All ported alignments have a subsonic filter at 20hz.


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## Owen Bartley

Ah, you guys! :nerd: lol 

Thank you all for the suggestions, and Mike for the comparison graph. Now I'm wondering myself if I should increase the volume. I might be able to push it out to 2 cubes, but I'd like to keep it as small as possible. Something in between Mike's (blue) and the manufacturer's (green) might be just the ticket. Maybe 2 cubes tuned to 21Hz or so. I also have to keep in mind that the larger the port is, the more it displaces my external dimensions. I do like lower tuned subs though, since you only really have to worry about over-excursion below tuning freq. (usually?).


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## Mike P.

At 2 cubes tuned to 21Hz maximum excursion is at 18 hz with 300 watts input. SPl at 20 hz is 104db. With a subsonic filter applied at 19 hz, maximum excursion is never exceeded and SPl at 20 hz is 101db.


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## Owen Bartley

Thanks Mike!

I think I like that model. I tried to run it in WinISD, but was having problems so I went to Unibox. I modeled it at both 1.5 and 2 cubes, and it doesn't look like it gives up a lot between the two. If that's true, I'd stick with the smaller one. If there's more than I saw with this quick job, then I suppose I could live with the extra size. I know the 3" port is a little skinny, but with a flared end, will it really be a problem?


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## Mike P.

With 1.5 cu.ft. tuned to 21hz with a 20 hz subsonic filter applied and 300 watts input, the maximum airspeed is under 26 m/s at 19 hz with a 3 inch diameter port. With a 2 cu.ft. box and all other inputs staying the same, the airspeed increases to 32 m/s.


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## Owen Bartley

Thanks Mike, I suppose 26 m/s is getting pretty high, but it isn't ridiculous, and I think it's doable. I'll run a few variations, but I think I'm getting pretty close to a final choice. I'm still very much open to input though!


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## Mike P.

I'm not sure what to say about this air speed issue. I just finished testing a IXL-12 in 3.5 cu.ft. tuned to 18 hz with a 4 inch diameter flared port. With the plate amp I was using, modeling showed 38 m/s at 18 hz. I tried test tones from 15 to 25 hz and I don't hear anything except the tone and the effects it has on the room. (Windows, doors and walls vibrating) There is a lot of air moving in the port, but no "chuffing sound" or any port noise that I can distinguish. I do know Collo did some port testing and found compression and turbulence start around the 26 m/s point, I think, but at 38 m/s I'm not hearing "port noises". I don't know, maybe different people hear different things. :dontknow:


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## Owen Bartley

I think the turbulence starts at different speeds for different diameters... the smaller the diameter, the lower the turbulence begins. So theoretically with 3" I'd hear it sooner than with 4", but to move up to a 4" port, it would have to be significantly longer to achieve the same tune. I can just chalk this up to a design compromise, and live with some minor chuffing at high volume with very low frequencies.


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## eyekode

Owen Bartley said:


> I think the turbulence starts at different speeds for different diameters... the smaller the diameter, the lower the turbulence begins. So theoretically with 3" I'd hear it sooner than with 4", but to move up to a 4" port, it would have to be significantly longer to achieve the same tune. I can just chalk this up to a design compromise, and live with some minor chuffing at high volume with very low frequencies.


I do in fact hear air turbulence around where it is predicted with a 4" precision port. For my design this was ~97-100db or so @20hz if memory serves. That being said I don't care because by this point my windows/blinds/lamps, doors and even Tv are making more noise then the port.


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## Owen Bartley

Finally got my build started HERE.


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