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Could you please recommend BASS DRIVERS for an OPEN BAFFLE SUBWOOFER used in the following set up:Application: home PA (DJ sound system for dance parties)
Room size: 30'x20'
Equalization/crossover provided by: DBX driverack PA
Rest of system: Panasonic 100w/ch digital amp, Fostex FE206E sattellites in small sealed boxes (equalized, high pass @ 180 Hz)
Budget for subs: $300
Goal: the best quality bass for $300Please, don't tell me to use sealed or ported subs. I want diapoles for their sound quality and room acoustic properties.
I have enough room for big subs and a great DBX eq for frequency correction.
Thank you
Herman
Follow Ups:
Basically what you want are drivers with low Fs (under 25, but under 20 would be better), low Q for good sound quality (under 0.5), and lots of X-max for the capability of playing at a sufficient volume at the lower frequencies (the less x-max that you have, then the more drivers you need). Cast frame drivers would be better than stamped frame drivers. I would recommend the same drivers recommended by the infinite baffle people. See this:http://www3.sympatico.ca/bonaz/IB-Sub/IBdrv-01.htm
There is a trick that you could use to get a decent output at lower frequencies from open baffle. Providing that you only need the open baffle sub to work below 100 hz (above 100 hz you will have resonances caused by this box design), then you could build a W-style box where the mechanical forces cancel each other (see Linkwitz design for the Phoenix open baffle sub). Then you could attach a second rectangular box to the common opening on one side of the box that addes to the path length (having a path length from one side of the woofer to the other side of the same woofer of over 40 inches or more) and reduces the point at which cancellation takes place to a much lower frequency.
A more efficient system with similar sound quality to open baffle would be to do an infinite baffle system providing that you have a separate room available to you that could serve as a very large "box" for your woofers.
Retsel
"Please, don't tell me to use sealed or ported subs. I want diapoles for their sound quality and room acoustic properties."Then there is nothing to say, because an "open baffle" will not work for a sub. The front wave will cancel the rear wave. Sorry, physics is a real, uh, problem.
that's patently incorrect, and in fact, dipole subs have an enormous amount of verbeage 'wasted' on them.it also wires two woofs, front facing in phase, rear out of phase-- to mitigate said cancellation.
best take a look around online before stating something won't work.. dipole bass is real, and physically possible, and certainly appreciated for its sound quality- especially in the application noted.
take a peek at the linkwitz labs (of that acoustician of minor import-- e.g. linkwitz-riley filter, which i presume you've heard of) website. pretty cool stuff.
d
d.
I know what an open baffle is, and I know what a dipole is.Take a sealed bass cab. Remove the back panel. Now it is "open baffle". No bass. Same effect as the 17 yr old with a pair of 6x9's sitting loose on the back deck of his 77 Chevelle, who wonders why his speakers won't make any bass, but is too lazy to cut some holes and mount them properly.
Here in the real world, as a working musician, and having built speakers for about 40 years, I stand by my original statement.
"an open baffle will not work for a sub"
That's not entirely true. With proper placement, the right room interactions, lots of big drivers and a huge amount of power it can be done. It's not as practical as a horn loaded sub that can knock plaster off walls and blow out candles fifty feet away with only one woofer and a hundred watt amp, but it can be done.
Thank you, Bill. My point exactly.For a $300 budget in a 20' x 30' room, OK, I'll take that on.
There are a gazillion places on the web, or you can email me, where you can find the plans for the JBL 4530 aka Eminence Scoop aka Fane Scoop(you get my drift) 15" "scoop" or rear-loaded horn bass cab.
Buy your birch cabinet plywood, carpenter's glue, and some screws and start building. If you are never going to move these to clubs, leaving them permanently in your party room, save some money by using MDF, but ONLY if they are never going to be moved.
Stick in an Eminence Kappa-15. Not the Kappa Pro-15, or the Kappa-15LFA, just the plain Kappa-15.
Or if you can get a good buy on cabinet grade birch ply, and watch where you buy your drivers, you may be able to build two of these cabs using the less expensive Eminence Gamma-15.
These two drivers, the Kappa-15 and Gamma-15 have high EBP (around 100) and low fs (below 40 hz, the cutoff on these cabs) and are well suited to this cab design.
You can save time, money, and aggravation by leaving out that curved section in the mouth, and just putting in a flat section at a 45* angle. Make that piece 22 1/4" w x 18" (the inside width of the mouth is 22 1/4" wide), and cut the top and bottom edge (the long edges) at a 45* angle. It will work just as well.
Also, these cabs will have big flat tops on which you can stack your midwoofers and hf horns. Either that, or your partygoers will leave their empties there.
OK, so the Scoop only goes down to 40 hz. But it will really do some damage from 40 hz - 100 hz.
While I wouldn't recommend any traditional rear-loaded horn or 'scoop' as a sub, Danley's tapped horn is a rear-loaded design that works well. As far as front loaded horn subs go there are more than a few that come in under $300 build cost, I've got a couple on my website, there are others.
I think a BR box would be best here, too, but if you are set on an open baffle design, you want a driver with a Qts as close to 0.7 as possible. Eminence makes some pro drivers with a highish Qts (about 0.6 or so, if I remember correctly). The 15" Definimax 4015LF has a Qts of 0.5, the 18" Kilomax Pro 18 has a Qts of 0.56, the Delta 15A 0.53, the Delta 15B 0.61.
Maybe this will help.
For a DJ system?Aint gonna cut it...
Go to Speaker asylum cause your not talkin pro audio gear here
Richard Greene bassnut will steer you on a dipole sub setup
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