12 inch car sub in B&W 801 cabinets? - Page 2 - diyAudio
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Old 25th December 2012, 03:44 PM   #11
sreten is offline sreten  United Kingdom
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Quote:
Originally Posted by audiomagnate View Post

No, 801s use 12 inch bextrines. I have entered enough data, and it looks
like sealed vs. vented means down 11 dB at 20 Hz vs down 5 dB vented.

That is rather huge. It looks like I'll be doing some cutting. It doesn't seem
to matter much which vented system I use i.e. 3dB shelf, Quasi Butterworth
etc. A 4 inch port 24 inches long is what it calls for, more or less.
Hi,

Can't argue with the numbers, that is what I found. Its best to optimise
f-6dB or f-10dB to get a sealed like alignment (but much deeper) with
very good powerhandling in the very low bass (due to port tuning).

18Hz tuning looked very good to me, nice room friendly roll-off,
which will sound almost as tight as sealed, just a lot bigger.
(I choose tunings based on what looks good to me depending on
the shape of the rolloff - which determines transient response.)

rgds, sreten.
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When your only tool is a hammer, every problem looks like a nail - Abraham Maslow

Last edited by sreten; 25th December 2012 at 04:08 PM.
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Old 27th December 2012, 06:52 AM   #12
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This has to be the cheapest way to build a good sub. My next project will be a pair of 15" car woofers installed in a pair of very large and very well built Pioneer HPM-150 cabinets.

Step one: Buy large, well built vintage speakers with at least some salable drivers and or other parts.

Step two: After selling off original drivers on auction site, plug any holes left by missing drivers.

Step three: Purchase appropriate car woofers off of local CL after running the numbers of said drivers through WinISD using your vintage cabinet's volume. It's amazing how cheap people sell 12 and 15 inch car woofers, often new in box for a fraction of the original retail. Excellent drivers can be had for as little as $30 each!

Step four: Install new car woofers, port, maybe new terminals and/or plate amp, damping materials, and there you have it! If you've done it right you have a very low cost, or maybe even free (if the original drivers are valuable) excellent sub. A bonus is that they can be built in pairs.

Someone else HAS to be doing this.

Last edited by audiomagnate; 27th December 2012 at 07:13 AM.
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Old 30th December 2012, 10:04 PM   #13
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After running lots of locally available woofers through WinISD, it looks like the MBQuart PWH 302 will offer the best response, down only 3 dB at 20 Hz in my 3.9^3 box tuned to 18 Hz.Here's a link to the TS parameters if anyone wants to check my work. http://www.maxxsonics.net/manuals/mb...fs/pwh_302.pdf

The curve looks almost too good to be true so I'm worried that I made a mistake.

Last edited by audiomagnate; 30th December 2012 at 10:09 PM.
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Old 30th December 2012, 10:43 PM   #14
sreten is offline sreten  United Kingdom
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Quote:
Originally Posted by audiomagnate View Post
After running lots of locally available woofers through WinISD,
it looks like the MBQuart PWH 302 will offer the best response,
down only 3 dB at 20 Hz in my 3.9^3 box tuned to 18 Hz.
Here's a link to the TS parameters if anyone wants to check my work.
http://www.maxxsonics.net/manuals/mb...fs/pwh_302.pdf

The curve looks almost too good to be true so I'm worried that I made a mistake.
Hi, the numbers pan out FWIW, rgds, sreten.

Flat to 40Hz and -3dB at 20Hz.
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There is nothing so practical as a really good theory - Ludwig Boltzmann
When your only tool is a hammer, every problem looks like a nail - Abraham Maslow

Last edited by sreten; 30th December 2012 at 10:48 PM.
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Old 30th December 2012, 10:47 PM   #15
6L6 is online now 6L6  United States
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Remember to try stuffing the port with a big wad of rolled-up speaker stuffing or even a few socks to try aperiodic loading. I've found it to be the best for a music subwoofer.

It costs nothing to try, and nothing to revert if you don't like it.
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Old 30th December 2012, 10:53 PM   #16
sreten is offline sreten  United Kingdom
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Quote:
Originally Posted by 6L6 View Post
Remember to try stuffing the port with a big wad of rolled-up speaker
stuffing or even a few socks to try aperiodic loading. I've found it to
be the best for a music subwoofer.

It costs nothing to try, and nothing to revert if you don't like it.
Hi, porous foam lining the port to detune it works a lot better, nearly always, rgds, sreten.
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There is nothing so practical as a really good theory - Ludwig Boltzmann
When your only tool is a hammer, every problem looks like a nail - Abraham Maslow
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Old 30th December 2012, 11:19 PM   #17
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Glad to hear the numbers pan out. I will pick one up tomorrow after testing it. It seems whatever woofer I plug in, the solution is always a four inch, two foot long tube, plus or minus a very small amount. What should I use to make the tube? What if there's no room for a tube that long?

Last edited by audiomagnate; 30th December 2012 at 11:23 PM.
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Old 30th December 2012, 11:32 PM   #18
sreten is offline sreten  United Kingdom
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Hi, Porting at Subwoofer-Builder.com , rgds, sreten.
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There is nothing so practical as a really good theory - Ludwig Boltzmann
When your only tool is a hammer, every problem looks like a nail - Abraham Maslow
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Old 31st December 2012, 10:30 AM   #19
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Those bizarre looking external flared ports are interesting. That shape is easy to make on a ceramics wheel.
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Old 1st January 2013, 10:52 PM   #20
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I have one sealed version going. That woofer sure does move more than I'm used to. Less sensitive than my big Infinities.
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