Decent 18 inch woofer for a 7.5~8 cubic foot bass reflex enclosure? - diyAudio
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Old 9th July 2011, 04:44 AM   #1
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Default Decent 18 inch woofer for a 7.5~8 cubic foot bass reflex enclosure?

I have slowly been building a large subwoofer enclosure for primarily HT in a large, irregular room. It is almost a cube but is not as deep as it is tall and wide, has two circular ports in the front baffle to the bottom left and bottom right of the woofer (was this a bad idea vs a single wide rectangular port like many large enclosures seem to have?) that will be tuned somewhere between 17 and 22 Hz. Many woofers seem to recomend oddly small enclosure sizes, such as the $1,700 Focal 46kx4 18 that recommends around half that ported. The enclosure is made out of regualar plywood (I know, shoot me now) but that is because it may need to withstand some moisture without turning into a little ecosystem, but it is three layers thick, coming out to be 2 full inches all around (1/2", 3/4", 3/4"), I have not braced it yet, but when I threw crap Pyle 18 (blue wave- 85 dB sensitivity, do they get any worse?) in it, it made some good noise with zero significant flex/resonance. Bracing would bring the enclosure volume down to about 7.5 cu ft I'd guess. The enclosure would be meant to cover as low as 20 Hz up to only 60 Hz, maybe just a little more, but not much because the plywood seems to resonate above that. Also because I like "regular" speakers to have a little more fullness, as they do a better job with accurate mid/lows due to their smaller size and much better agility. Low, rich good bass preferable, make that needed, over loud car style bass full of overtones that sounds like a canvas being ripped.

WoofersEtc.com - 46KX4 - Focal 18" 2000 Watt K2 Power Subwoofer

Wait a minute, it's given a frequency response of 50-500.... what kind of bull is that? 96.5 dB sensitivity is great for a large woofer. I thought it was the tighter suspension, smaller surround/lower excursion woofers, which is kind of what this is, that were actually more well suited to large enclosures; however, this thing is said to be intended for fairly small enclosures, though I am leery of the given specs.

Okay, I see on crutchfield it says freQ 20 to 500, that's better. But what's still B.S. is that it says power handling 1000 watts nom. then it says (250 per voice coil) which is bull because if you were using just one or two voice coils (which can be done all right, you just need to recalculate some T/S parameters, I actually ran the Pyle with two different identical non-strapped amps set the same, one for each coil so they could run at a higher impedance because they're cheap amps) they should be able to handle relatively more thermally becuase even though they are all seperate coils, they're all on top of each other. Crutchfield also gives the sensitivity as 93.5 that's a huge difference.

http://www.crutchfield.com/S-Pf1KCLE...r-46-KX-4.html

Last edited by Upstate NY low life; 9th July 2011 at 05:06 AM.
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Old 9th July 2011, 12:10 PM   #2
triode3 is offline triode3  United States
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If you can do 8 cubic feet, build that, port it to 20hz, and buy a used JBL 2245h. I have one in 8 cubic feet ported to 22hz. JBL claims 95db 1w/1m. I find that a good 90W amp can cause devastation in a large room (32'x16') with this setup. Deep, effortless smooth bass.

It may not be the "best" solution, but I picked up a pair a while back for $100 each. Fs of 20hz, not a huge x-max, but its 18" of cone area. Read the papers on it at lansingheritage.org (they even have plans for an 8 cubic foot enclosure and a 12 cubic foot enclosure). If you have the room, its a great sub on the cheap. I have to get rid of mine as it is too big.
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Old 9th July 2011, 01:08 PM   #3
doug20 is offline doug20  United States
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Search for Fi Q18 subwoofers. Its the only 18" choice I know that is even below $300 (I think) and it will work well in a large ported enclosure. Make sure you email Ficar and explain what you want and they will modify the driver to work for that design (ie..change the Q and surround a little bit).

Find a used pro audio 18" is not a bad idea either. IF you only want 20Hz, you could check out the TD18H found at AE Speakers --- Superb Quality, Unforgettable Performance, Definitely.. That is s serious high performance 18" driver that you just need a high powered amp and sealed box, no reason to have 8 cuft ported inferior designs then.
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Old 9th July 2011, 04:08 PM   #4
60ndown is offline 60ndown  United States
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i saw this yesterday, id be tempted, use 2,4 or 6 and it has to out perform 1 single 18.


MCM Audio Select 18" Woofer with Paper Cone and Cloth Surround - 300W RMS at 8ohm | 55-2954 (552954) | MCM Audio Select
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Old 9th July 2011, 04:55 PM   #5
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Sensitivity 100 db/w/m.... that looks like a cheapo. It also has a 27 Hz fs. I mean, that's almost as cheap as the Pyle 18

I like the looks of the JBL

Last edited by Upstate NY low life; 9th July 2011 at 05:01 PM.
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Old 9th July 2011, 05:51 PM   #6
60ndown is offline 60ndown  United States
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Quote:
Originally Posted by Upstate NY low life View Post
that's almost as cheap
ive heard cheap systems that sounded great, and very expensive ones that didnt.

cost does not equate to great sound.
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Old 9th July 2011, 07:30 PM   #7
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You're going to spend almost $2k on a woofer?

Check out the TC 5100...its half the price and will go plenty low!
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Old 9th July 2011, 07:34 PM   #8
imix500 is offline imix500  United States
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Faital Pro's offerings are also certainly worth a look. TC Sounds also now sells a slightly redesigned Aura 1808.
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Old 9th July 2011, 07:42 PM   #9
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So who does buy the 2k woofer and what is for? Exotics? Like the sophisticated Dme people?

And I never said I was going to buy it. I said it caught my attention but was meant for smaller enclosures.
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Old 9th July 2011, 08:35 PM   #10
HK26147 is offline HK26147  United States
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Quote:
Originally Posted by triode3 View Post
If you can do 8 cubic feet, build that, port it to 20hz, and buy a used JBL 2245h. I have one in 8 cubic feet ported to 22hz. JBL claims 95db 1w/1m. I find that a good 90W amp can cause devastation in a large room (32'x16') with this setup. Deep, effortless smooth bass..
A friend of mine who retired from pro sound ( health reasons ) used to use 6 - 8 2245H ( in 8 cu ft cabs /driven by Macrotechs ) outdoors for crowds up to 10,000.
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