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Discussion Starter · #1 ·
First off thanks to all for the help on this. I have a 15" cerwin vega that I am happy with. Has plenty of output but just don't quite go low enough. So I am now ready to build my own.

The amp I will be using is the O audio 500. Seemed to be the best deal on a amp I could find, plus has plenty of adjustments compared to the bash 500 at parts express. As far as the woofer goes the Fi SSD 18" seems to be the best deal on a good woofer I could find. Not sure how good it will be for home audio use though. I was also thinking of using the Dayton Titanic 15". I haven't been able to find any other good large woofers in this price range.

Design goals for this build: Make a sub that will play as low as possible (atleast 18hz or lower) and as loud in those frequency's as possible with the power on hand. Stay in the $265 range for the woofer. Box size limited to the 15 cubic foot range. I am completly open to suggestions so please feel free. Box and port sizes would be appreciated. The room is 17x14x8 and one side opens up to the rest of the house. Thanks again guys. Can't wait to see what you guys have to say.
 

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Discussion Starter · #3 ·
Ok sounds good to me. Box will be around 48"Wx20"Tx26"D. I will be placing the sub in the center of the front wall under my projector screen. I really don't know where the best placement for the port would be (front, side, or rear) I have heard that the ports being in the back of the box keeps the sound in phase with the woofer. Don't know how true that is. i have always placed them firing in the same direction of the woofer. I hit 151db on the dash of my car with 1 fifteen and 1,100watts. So I wouldn't think that the port was out of phase with the woofer. I really would rather go with a slot port instead of a round port. I've never had problems with port huffing when I use these type of ports. Plus it will be easier to make long and bend it around the inside of the box. What size would the port need to be with 18hz tunning frequency? Thanks again for the help.
 

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Discussion Starter · #5 ·
Oops. No that isnt what i have to work with. Just did the math wrong on the 14 cube box. Just throwing some measurments out there. I am really not limated in size much. I can go 8' wide 24" high and around 30" deep. Ill build whatever it takes to acheave the really deep bass that I want. Just wanna make sure after I go through all this work, that its going to perform great.
 

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Discussion Starter · #7 ·
Rite. Ok now all I need is advice on port placement and size. Again I would really like to stick with a slot port. Especially if the port should be placed on the front or back of the box. Unless it would be good to place the port on eigther side of the box. Then a round port shoud work since it wont have to be bent to fit the box.
I ordered the amp today. Gotta sell some of my rc stuff to get the rest of thr money for the woofer. I can't wait to get started. Its always been my dream to build a huge sub. Plus the fact I have never evan seen a 18" woofer in real life. I will post plenty of pics when done. Do you guys think making the box 1.5" thick with a 2.25 front baffle will be good enough with bracing? Or shoukd I go thicker?
 

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Just to throw this into the pan. Here's a model of the following:

14 cu ft SSD 18 tuned to 18hz with the 16hz hpf. 500 watts input power

14 cu ft SSD 18 tuned to 15hz with no hpf (max excursion is reached at 14hz). 1000 watts input power

8 cu ft SSD 15 tuned to 18hz with the 16hz hpf. 500 watts input power

I think with the 500 watt plate amp you would be just as well to go for the 15" driver. You are only 2db down from the 18" and you are 6 cu ft smaller. You do loose a little in the upper bass area but you would be EQ'ing your response flat anyway and it depends on your room what your actual response will look like. Also the same goes with room gain too.

With the 14 cu ft tuned to 15hz and 1000 watts you would be 12db up with the same box tuned higher and hpf. If you are set on the 0 Audio amp then I would go for the 15".
 

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Discussion Starter · #9 ·
Wow I really appreciat you goin to the trubble of mockin that up for me. Hmmm. I really had my heart set on that ssd 18 :'( So as far as woofers go. Should I get the ssd 15 or the Dayton Titanic 15? Or is there a better 15" in my price range?
 

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Discussion Starter · #11 ·
Hmm the titanic does look pritty good. Is the green line the 18 with 1,000 watts or 500? Looks like it would get down 3-4 more hz at 2-3 more db than the titanic. If thqts with 1,000 watts then The titanic is def the clear winner. If its with 500 though seems like it might be worth it? 3db at that low of frequency would be very noticable rite?
 

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Discussion Starter · #13 ·
Ok yaeh thats a no brainer then. What imwould be the best placement for the port ( front, rear, side) what size slot port should I use for the 12 cube box? Thank you very much for the help to. Thats defanitly ganna saze me some money and work
 

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It kind of depends on how you want to do the port. A slot port can really be anywhere. I put the port going down the back off my subs firing out the top.

22" wide by 44" high by 28" deep would be around 12 cu ft. You could do the port 20.5" by 2.25" by 40".

You can do the port any size or shape just make sure port resonance is higher than 150hz and velocity down to the mid 20's or below.
 
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