Tempest DIY. A few questions please (1 Viewer)

[Chris_Campbell]

Hello all, I'm nearing completetion of my tempest sonotube sub, and I have a few questions. But first, here is a little info to help: it's approx 9.2 ft^3, receiving 750 watts, tuned to 20 hz, with ports 15.1 inches long (2x4" diam).
1. Unfortunately due to build complications (and this being my first DIY) I couldn't get one of the ports to stand exactly verticle in the enclosure. Will this cause a problem? It's tilted about 10 deg to one side.
2. I'm using plumbers PVC for the ports, and no flares

Will this cause problems?
3. I'm planning to run the speaker in series because my amp (carver pm350) won't do a 4 ohm mono load, but will do 16 ohm mono (interestingly puts out 750x1 @16ohm, and only 350x2 @8ohm stereo). Will this cause any problems over a parallel config?
4. So far I'm not using any kind of stuffing or batting. Is this really neccessary?
Thanks folks for all your help the whole way through. I just hope this thing comes out to be more than a hack-job.
Chris

 

[DanWiggins]

Chris,
1. No problem.
2. You'll lose a bit of output at peaks; for most listening levels, though, it won't be a real problem (typically you'll be running less than 100W into that design; peaks will be higher, though).
3. No problem with series connection. And the power ratings of the Carver just mean that it's current - not voltage - limited.
4. I'd recommend some lining. Use either R-9 fiberglass around the inside, or 3 layers of 1" thick polyester batting (like used inside quilts). Personally, I go the poly route, because it's easier to use and less itchy. Also bunches easier, if needed.
Hope this helps!
Dan Wiggins
Adire Audio

 

[Chris_Campbell]

Thanks Dan, you've been a great help! Do you know where I might be able to acquire this stuff?

 

[DanWiggins]

Chris,
I assume you mean the polyester batting? Pretty much any fabric store will have it. Ask for quilt stuffing. It comes in a sheet form (typically either bagged, or off the bolt. Cheaper to buy off the bolt).
Dan Wiggins
Adire Audio

 

[Neil Joseph]

I was wondering the same thing about the lining. Is egg-crate foam good to use or would this polyester batting be better?
orangeman
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[Patrick Sun]

Use whatever requires less work. Both should be fine.
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