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Discussion Starter · #1 ·
Use: 95% Home theater, occasional gaming and music
Space: basement dedicated HT room; Studded drywall with insulation over cinder block; acoustic drop ceiling; approx 14' x 22'

I put quite a bit of time and effort into my HT about 4 years ago. Everything is wonderful, except the sub. I neglected it. Right now I'm using a pair of JL Audio 12" subs in a sealed truck box. They were great in my extended cab S10, but they SUCK in the HT. I'm powering them with a Peavey PV 8.5C amp.

So, I think I want to go with a ported design to get the low end. A large enclosue is fine. I've built automotive boxes before, but they've all been sealed. This will be my first ported one.

The Tempest-X2 15" looks like a good driver. I honestly don't feel like spending hours debated/researching T/S parameters and such. I just want a good quality, high bang for the buck driver.

I'm generally a hands on, do it all myself kinda guy. However, I don't think I need to reinvent the wheel with the enclosure design. Are there any sources of preconfigured designes out there?

Would my Peavey PV 8.5C be a good power source for this sub or would you recommend a plate amp? Obviously, I'd need to invest in a subsonic filter if I use the Peavey. I tried to post a link to the amp specs but the site won't let me just yet {4 more posts to go :)}.

Surely I'm not the only one out there that wants to build a sub, but doesn't want to spend hours reading specs and working with design software calculating port dimensions? ...or am I? I'm an electrical engineer, so I could do it. However, free time is short when you have two kids in grade school and a wife that works.

Thanks in advance for helping out a newbie!
 

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Discussion Starter · #3 ·
Currently looking at a sonosub design. What are the pros and cons of sonosubs (tubes)?

Pros: light weight, easier to build

Cons: ???
 

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Discussion Starter · #6 ·
Designing a sonotube is easy if you state how much power you will be using. Once that is known I can post a diagram for you.
From the Peavey manual:

PV-8.5C: 425 W RMS into 4 ohms: 550 W RMS into 2 ohms (per channel)
850 W RMS into 8 ohms; 1100 W RMS into 4 ohms (bridged)
 

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Here a graph of the ball park SPL without room gain with 1000 watts. You'll need a hi pass filter at 16 hz to protect the sub from over excursion at the lower frequencies.

rob spl.JPG

Here are all the dimensions you need to build a 22" diameter sonotube with a 6" diameter port. The legs need to be 4" high.

rob sono.JPG
 

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Discussion Starter · #12 · (Edited)
I did some modeling of the JL Audio 12W4s that I have. They don't look too bad. I might just build proper enclosures for them first. If they don't meet my expectations, I'll sell them and build one with a modern driver.

WinISD seems to spit out ideal parameters for you, right? How do you adjust for a LLT design? Box volume x 1.5 or 2. Then increase the port diameter?
 

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Discussion Starter · #13 ·
Both tuned to 15Hz with 1000 watts

Tempest X:
port 6" diameter 14.35in long
18 ft^3

JL 12W4:
port 6" diameter 21.5in long
13 ft^3

Thoughts? Keep in mind that I already have two of the JLs.
 

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Discussion Starter · #15 ·
Upload the JL file so I can have a look.
Thanks for the offer Mike. The JL 12W4 is a stock driver in WinISD. However, some more investigation show the Xmax of the JL is only 0.4 inches (WinISD lists it as 0.34). That will severly limit power handling at the low frequencys. Even a traditional ported design will be limited to about 108dB at 100w.
 

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Discussion Starter · #17 ·
I think I'm gonna go with a Maelstrom X in a LLT sonotube. How does this look for a start:

20 cubic feet
24" diameter enclosure
8" diameter port 24" long
tuned to 15Hz
powered by a 1,000W Peavey PV 8.5C amp

Thoughts?
 

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Discussion Starter · #19 ·
I just ordered a Maelstrom 18". I picked up a 8" X4' sonotube at Home Depot. I had to go to a concrete supply store for the 24" X 12' sonotube. Bringing the big sonotube home in the minivan was interesting but uneventful.

Any reason not to use MDF for the end plates/caps?

I think I'll start a new thread for the build.
 
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