# Need help with new sub.



## ace27 (Feb 24, 2008)

Hi, I was looking at buliding a new sub. Something sealed with a couple PR's to help keep the overall size small. Right now I have a SDX-15 sub and a ep-2500. I was looking at WinISD and was thinking of something around 3.5 to 4 ft3. As for the PR's I saw the 18" 2100g ones at CSS and the 15" 1400 grams and have no idea what to pick. I have never used PR's and dont know a whole lot about them. Im interested in what others have used. Thanks!!


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## Mike P. (Apr 6, 2007)

What size box is your SDX15 currently in? Sealed or ported?


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## ace27 (Feb 24, 2008)

Its in a 12.5 ft3 box that is ported. Its not that its a bad sub its just that I would like to make one a little smaller. If I can use one or two PR's to help the build out I will.


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## Mike P. (Apr 6, 2007)

Tell me what the tuning frequency is on the 12.5 cu. ft. and I can model a comparison for you.


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## ace27 (Feb 24, 2008)

Its around 15 hz.


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## Mike P. (Apr 6, 2007)

Green is what you have, 12.5 cu. ft . tuned to 15 hz. Both pink models are in a 24" cube with a pair of the CSS 15" PR's. Shown is the various tuning by adding washers to the outside of the PR. a Hi-Pass filter is required at 18 hz to protect the PR's from over excursion. Input power is 1000 watts for all models.


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## ace27 (Feb 24, 2008)

Mike, thanks so much for the replys they are great. I have a little problem on my end, I can't get the same numbers on WinISD that you get. I picked the SDX-15 sub and checked the specs to the ones on Funky Waves, as goes for the PR's, I went with the 1400g ones with the specs on CSS. In WinISD I left the added mass to cone at zero and still get a tune of 16.74hz and can't get it any higher. Not too sure what I am doing wrong. Thanks!!


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## Mike P. (Apr 6, 2007)

Here are the specs for the CSS APR's that I modeled with. 

http://creativesound.ca/pdf/APRG.pdf


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## ace27 (Feb 24, 2008)

Hey Mike thanks for the link that is a way better PR to use, better than what I was looking at. The ony prob is I still cant get my WinISD to look like yours. Here are my specs. VAS 463,FS 19HZ, XMAX 33MM,QMS 7, SD 800CM2,2 PR's, 0 mass added and the SDX-15 sub selected. This looks like the set-up I will go with it just would be nice to be able to see what will happen when I add more mass to the PR. Thanks.


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## Mike P. (Apr 6, 2007)

Here's the project file. Save it to the Projects folder in WinISD. Add or subtract mass in 45 gram increments as that's what the supplied washers weigh. Have fun!

View attachment SDX15 2xAPR15 HPSA1000.wpr


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## ace27 (Feb 24, 2008)

Thanks again Mike for the post, I see what I was doing wrong, I had no weight on the PR's. One question to ask however. On the CSS page under the link to the APR-15 it also says that the washers are also 45 grams as well but the specs page says the are 50 grams.....Not too sure what is the right one to follow. Thanks!!


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## Mike P. (Apr 6, 2007)

Use 45 grams per washer, thast's what they have been measured as.


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## ace27 (Feb 24, 2008)

Thanks for the spec mike. I ordered the APR's and a few other items from CSS today and asked what was the right number to go from and was told the same from them as well. Hope to have the stuff by the weekend and can start to build the box!!!!!


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## Mike P. (Apr 6, 2007)

Sounds good! Take lots of pics and start a build thread! :T


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## ace27 (Feb 24, 2008)

Mike, I have another question for you. Would it be worth it to stuff the box or not? Thanks in advance!!


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## Mike P. (Apr 6, 2007)

If you were to measure the sub in room and find it had a peak in the response then yes. Build the sub and see how it performs first.


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## ace27 (Feb 24, 2008)

I was able to put some time into a box this weekend and here is what I got.










































So far I am ver happy with the quality of this sub. The two PR's are great!!


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## Mike P. (Apr 6, 2007)

Looks good. What did you finish the cabinet with?


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## ace27 (Feb 24, 2008)

Thanks, I used a rubberizer undercoating. I turned out better than I thought it would.


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## ace27 (Feb 24, 2008)

Well I picked up a RS spl meter and was trying a few tests with the sub. What I found was that with a 30 hz test tone playing, I sit in my sweet spot and have the meter set on 80db C weighting and slow action I am at 80db on the nose. As soon as I move left or right the meter will climb, and fast. I can easily get 10 db more as I get closer to the walls and stay the same distance from the sub as the main listening position. If I get into a corrner it is even worse. What can I do to even out the bass level throughout the whole room??


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## Mike P. (Apr 6, 2007)

Try different sub placements if possible.


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## BigHonu (Nov 14, 2009)

Build another sub!


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