# Not 100% happy with my new sub



## dougc (Dec 19, 2009)

Let me clarify, LOVE the sub (CSS SDX15), not in love with the new enclosure I spent tons of time building. 

I have had it up for a couple of days now and am happy with how it sounds for movies, but not so much with music. I need to get a subsonic filter for it for sure since I had some distortion on louder low end tones. It digs DEEP for the low end in the explosions and machine gun fire when I watched Heat last night, and it blends well with my mains. This part fits the bill, it's what I wanted it to do for movies.

In music, it lacks the punch and sheer volume of bass that the sub produced when I had it in the temporary small slot ported spec box made for an old 13w7. I actually am much happier with the overall sound it produces in that box for all music. I would say that the temp setup is easily 4x as loud with no distortion. SPL is not my main goal for the project, but I want it to be there when I turn the dial. The temoporary box won't dig quite as deep as my new enclosure, maybe 5% of the lowest frequencies are not produced. The first thing I noticed with the new enclosure is how low it reaches (and then how not loud it is).

I am considering using an identical design of that temporary box with the exterior to match this build if I can get the subs to blend. *Is there an issue of using two differently tuned subs together?* The one I just built for the deep end and building another smaller enclosure to cover the loud, punchy sound I am missing from music.

Here is a pic of the new enclosure:









Here is the new build thread:
http://www.hometheatershack.com/for...s/24901-dual-sdx-15-6-8-cu-ft-tuned-19hz.html


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## Mike P. (Apr 6, 2007)

What is the net volume and tuning frequency of the temporary small slot ported box?


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## dougc (Dec 19, 2009)

2.375 cu. ft. 
tuned to 34.59hz 
f3 31.0
25.25 in. x 17.25 in. x 16.5 in.
slot port 2.0 in x 15.75 in x 25.375 in.
port extension 7.875 in.


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## Mike P. (Apr 6, 2007)

Pink is 6.8 cu.ft. tuned to 19 hz. Orange is the small slot ported box, the hump in the 50 hz range is the "punch" you are looking for. Yellow is 6.8 cu.ft. tuned to 19 hz with 3 db of boost at 50 hz. That should give you back most of the punch.


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## dougc (Dec 19, 2009)

hmm... guess I need to get the b2 before I build the other one. 

I would guess that the actual output of the pink line would be 20-30db less all the way across and the orange line is closer to accurate right now as it is. *Is there anything that I could have screwed up in the build? Too much insulation?*


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## Mike P. (Apr 6, 2007)

> Too much insulation?


Good point. Remove the insulation and see how it sounds. Any chance you could get a SPL meter and take some measurements?


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## dougc (Dec 19, 2009)

I will try taking the insulation out of the ends first. There is only a single layer on the back wall, which I will leave at first. I just ordered the B2, and the 2nd SDX15 is next on the list before he sells out, so I will try and track down the spl meter after that


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## Ricci (May 23, 2007)

Ddi the enclosures get placed in different locations when they were listened to? That would make a huge difference. As you can see from the grpahs that Mike posted the difference would only be 3 or 4 db near 40-60hz between the small ported and the deep tuned ported pink trace.


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## dougc (Dec 19, 2009)

That is the weird part Ricci is that the only change between the two is the enclosure. All other settings were unchanged. The sub is placed right under the main speaker on the left


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## Mike P. (Apr 6, 2007)

Since you are hearing more then a 3 or 4 db difference near 40-60hz you should verify that the coils are both working and the sub is wired correctly. A process of elimination will help narrow down where the problem may be.


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## dougc (Dec 19, 2009)

The difference is HUGE. At least a few times more sound before I installed it in the new enclosure. I already checked the phase, I will check the sub again when I yank the insulation. I'm anxious to figure it out. I'll do these things before adding the b2 to the mix - which will get here next week.


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## Mike P. (Apr 6, 2007)

If the difference is that much then I would first verify the coils are both working.


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## dougc (Dec 19, 2009)

Update:

- Both voice coils work. I received the B-2 and the 2nd SDX-15 and set it all up. 
- I removed all the insulation except what is directly behind the sub on the back wall.
- I set the HPF at 20db on the b2, the sub still distorts at a max of 90db at almost any frequency I try
- The b-2 doesn't really do what I had hoped, but it does allow for some more control
- I put the new sub in the small slot-port enclosure for comparison between the two 
- I haven't metered the small enclosure, but it is loud as hell, and reaching nearly as low as the new enclosure, prefect for music (for me)
- both subs are powered by it's own EP2500

Side by side, both sound amazing together: punchy in the small enclosure, and the new enclosure is so deep it gives my wife a stomach ache, she says. I am considering building a similar small enclosure tuned the same and round port in the front to match the other. I will meter both side by side when I get home tomorrow and post the results.


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