amp and box for diy 12w7

Car boxes are tuned with a very small area in mind (a trunk). So they will sound and perform very different in an open area. In a car I think a w7 needs 1.5cf for a ported box if my memory is correct. I think you would want much more like 5-6 cf in a HT environment.

Hi Thomas,

Is that the same as the 12W7AE specifications wise?

Free Air Resonance (Fs) 27.2 Hz
Electrical “Q” (Qes) 0.514
Mechanical “Q” (Qms) 7.807
Total Speaker “Q” (Qts) 0.482
Equivalent Compliance (Vas) 2.33 cu ft / 66.0 L
One-Way Linear Excursion (Xmax)* 1.15 in / 29 mm
Reference Efficiency (no) 0.249%
Efficiency (1 W / 1 m)** 86.2 dB SPL
Effective Piston Area (Sd) 84 sq in / 0.0542 sq m
DC Resistance (Re) 2.47 Ω

?

For home theater use, a simple sealed box may be your best friend to keep port noise out of the equation and box design and size reasonable. 2-3ft^3 should be your absolute minimum. At 1000W, a 2ft^3 box will just barely let you touch on the Xmax rating at 10hz. A larger box will let you hit Xmax with less risk of thermal failure. I would personally want more like 3-5ft^3.

The Crown XLS series is rated for 4 ohm bridged loads. The driver you have in mind is 3 ohm.... I suspect it won't be a problem, just keep an eye on the amp, be careful you don't overheat it.

The JL recommended sealed and vented boxes for the driver are not what you want for a HT sub.

Personally, I think the driver has the greatest potential as a killer HT sub when loaded into a really radical 6th order bandpass bordering on compound horn/line type box... It's the only way to get a box design that both allows the driver to stretch it's mechanical legs without running out of thermal power handling, while also getting generous box gain. It would be a complicated custom build, probably around 10ft^3 external dimensions when all said and done though.

Regards,
Eric

at 5 cuft, if you plan to play at reference levels you may want to incorporate an amp or EQ that will allow you to put a high pass filter in place to protect the driver, as you will overexcurt with rec. power in a 5 cuft box.

yep, it does I do believe the actual load the crown will see will actually be a little lower than 3 ohms, in regards to the w7 specifically. Where most HT subs will show slightly higher impedance than their actual rating, the JL W line actually measures less. Will you still be ok? perhaps, but definitely keep an eye on the amp and make sure it isnt heating up too quickly.

The Hpf on the crown will not go low enough for your use. I have an xls1500 and the hpf doesn't go below 50hz if my memory is correct.

The natural crown rolloff might work fine for you in that case as well. The Crowns including the xls series start to roll off a little more than other amps at around 20hz. I ran my F-20's without a HP the whole time I had them.

I run my f20s without a hpf on my crown xls-1500. I wasn't sure about the rolloff, but wasn't hearing any indication the drivers were straining at any point.

If you're okay sacrificing 20hz output that will work very well. 5ft3 tuned to 25hz gives a natural 2.5db peak at 28hz, but when you set the 30hz HPF it flattens out to a -3db point at 25hz. You can also dump the entire 1400 watt bridged output of the qsc1450 into the sub while only hitting 20mm excursion.

You can do the same thing with a much cheaper Behringer EP4000.

the ep4000 is the same as the ep2500 just renamed. the eq.2 is a great "Quick eq" unit but the hpf is a little querky on it. I had one in my chain for a little while. for a 20hz hpf, and all you need to work it, just look at one of the beringher Inukes, they will have built in dsp as well (just eliminates one less piece in the chain) if you arent too concerned, then the berry 4000k and the eq.2 will work just fine. only two bands of eq on that though and you might end up needing more if you really want to get the sub dialed in.

IIRC the eq.2 has no gain so WFO in=out AKA unity gain...

Behringer makes a rack piece called the MIC2200 it'll do what you need. It's a bit odd though as the filter goes only down to 20hz and if you want a lower cutoff you need to boost with the built in PEQ, with that you can make good filters down to 10hz. You'll need to use REW to measure and dial in the filter.

Is the HP to gain output or protect the driver, or both ? I own (4) 1450's, they put out a good deal of current before any sign of clipping. I only clipped them once when i made an error EQing, my bad.

Nothing like clipping all four Adcom 555mkII's bridged, they gave up pretty quick LOL.

3.5cu ft sealed would be great, the RMX1450 would power that fine, then get ahold of a MiniDSP, plenty of EQ power to do everything and more, if you have the gear to measure with. Do you have measurement equipment....

Yup, bridge it for 1450watts for a single driver. We (as seasoned members) are trying to get more people involved in measuring to help integrate. Trying to keep the science that brought the product to their door.

Setting the HPF sometimes doesnt put it exactly where you want it. other than that it is a peach


EQ.2 DOES have gain control on it... PM me and Ill sell you one if you are interested I also have a berry mic220, dunno if that one is for sale yet or not though!!!

Just checked out some vids on utube about that driver, LMAO holy cow, does it do 4" peak to peak, what a world class machine. You may want to look a little closer at some models to be sure your ducks are in a row, hate to miss out on any of that insane woofage !!!!

I would try to let the box limit its throw and maybe rethink the amplifier.

Impressive video's though.......