I'd like to compile a post (maybe even a sticky!) which contains the frequency response curves for various subs under different environments. If anyone has any, please post them here and try to mention as much as is known about the testing environment (box type - sealed/ported/etc, sub size, THD, etc...).

Admins: if this catches on, this post will get kind of graphics-intensive. I hope you guys let it go this time.

 

and this explains why a lot of people aren't fond of the L7's in a sealed enclosure...

 

Here's a 12W7 which I found somewhere, but there were no details on the environment.

 

You need to keep in mind that there are so many variables associated with these graphs, that any sort of a comparison is virtually impossible.

In-car response is going to be drastically different than a response shown in an anchoeic chamber. In-car response from car A to car B is going to be drastically different.

And of course, this isn't even taking into account the enclosure that the woofer is in. Fooling around with the enclosure volume is going to have a tramatic effect on the response, which is why the most important information you can get for a subwoofer is an accurate set of t/s parameters.

I'm even very hesitant to trust the recomendations of the manufacturers these days. All of the hype is toward mega high excursion small box subs, so companies will fib a little bit to make their product look better in that regard. The Kicker is a perfect example. Judging by the frequency response of that sub that you showed, my guess is that the "optimal" sealed enclosure would be somewhere in the range of 5 or 6 cubic feet.

 

Oh, most agreed. That's why I was wanting as much about the testing environment posted. The strange thing is I agree that a 5-6 cu ft sealed box should smooth everything out, but Kicker states that the max size for a sealed box is 2 cu ft? I understand the smaller size helps with damping/cone control, but whatever...

 

I'm bored so I downloaded the T/S specs of that Kicker woofer and plotted it out in WinISD. We were wrong... it only needs 4 cubes.

For what it's worth, in 2 cubes, the box Q is .83, NOT .707 like they indicated. However, to Kicker's credit, the plot doesn't look much different.

I think part of the problem here, other than having a higher box Q than indicated, is that the high inductance and either cone mass or weak motor is causing a high frequency rolloff starting at around 70hz, which is just pathetic.

If kicker would use a higher quality motor assembly, or at least add a copper shorting ring or two to drop the inductance a little bit, this might not be such a bad sub other than the huge box requirement.

I also threw in the ported alignment that yields a .707 box Q. As you can see, it's MASSIVE. But, their tiny enclosures give a lot more output at the tuning frequency, which is exactly what the typical boomer idiot wants. You should see what this thing looks like in a 1.75 cubic foot box tuned to 50hz. There's a 7dB bump at 50hz compared to a box with a .707 Q.

 

The other thing that makes me wonder is if those specs are from a broken-in sub. I bought a pair of the 12s for a sealed box and upon first powering them on, they'd only play one note (an exaggeration, but seriously -- more or less that's how it sounded). They've only got maybe 6 hours of play and as the surrounds loosen I hear more & more frequencies emerging. On second thought, maybe a pair of 12W7's would have been better, but they would have cost just about twice as much. For the typical BOOM system, these subs would work great. I appreciate SPL, but SQ is also very important. I'll just EQ the livin crap out of these to get them how I want.

 

EQ will help, but there's no substitute for a low distortion driver.

I'm just finally getting my system in my Corvette going. I'm using an Adire Koda woofer and this is a very clean, very detailed driver. Once I get my massive midbass gap filled, I can't wait to really find out how detailed this driver is.

I think that for my IROC I'm going to try a Dayton Reference HF subwoofer or a Peerless XXLS. These drivers seem to exhibit extremely low distortion. I've heard a cardoid arrangement with a couple XLS woofers in a home environment and I was extremely impressed with the sound.