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View Full Version : Size of sealed box vs loudness



ultimate157
09-08-2006, 06:41 PM
First off let me say this: Assume a perfect install.

I have an Eclipse 8200. the SQ of this sub is amazing. However, there is no SPL at all. my previous 2 10" pioneer TS-W250R's had the ability to vibrate my rear view mirror.

I have the 8200 in a 1cube sealed. Recommended volume is .75 to 1.25.

However, I had some people on here tell me i needed like 5-8 cubes for it to be loud.

My question is this: All variables the same, is a higher volume box, sealed, for this woofer, going to be louder than a 1cube?

Also, how can I tell if a woofer is being cramped in a box?

amr952
09-08-2006, 06:44 PM
I am not sure about this but I will take a shot.

I beleive that it will get louder, but you will also start to lose control over it. So I beleive the power handling will go down as box size gets larger.

So It will be eaiser to over exert than if you had it in a smaller box.

EDIT 5-8 cubes souds rediculous though.

ultimate157
09-08-2006, 11:38 PM
Bump. Anybody know if you can tell if a sub is being restricted due to a box boing too small?

phantom240
09-08-2006, 11:43 PM
thats a possibility. Try ported as well.

heyman421
09-09-2006, 12:06 AM
if the sub is cramped in a sealed box, you will have an output peak, and a high freq. rolloff.

the bigger the box, the less presence of a 'peak' and a lower frequency -3db rolloff.

A ported box on the other hand, will gain ouput as you increase size, if you keep the tuning frequency the same.

There's a lot of variables here.

But no, i wouldn't expect more output in a larger sealed box. Only a lower rolloff frequency, and a smoother response curve.

ultimate157
09-09-2006, 12:15 AM
My problem is this woofer is designed for sealed boxes only. It says many places never to port this sub.

My problem i'm having is a very strong peak response. It's very loud (im guessing) around 45-50hz. lower than that it drops off like a rock. However, i've been told this woofer is a low end monster, which puzzles me why there is no low end response.

quicky specs: (its the 8200)
http://www.eclipse-web.com/sw8000/image/8200spe.gif

I'll get the 0db test tones out tomorrow and give you guys some numbers to work with.

Also, i get the POP whenever i turn my system off. how do i stop this?

vetkilr
09-09-2006, 08:50 AM
If your only gonna run that opti at 4ohms then Id make a box around 2 -2.5 cubes for it then to get more output from the sub and youll be happy again.

skeptikal
09-09-2006, 11:46 AM
However, I had some people on here tell me i needed like 5-8 cubes for it to be loud.
Also, how can I tell if a woofer is being cramped in a box?

really man whoever told you that is completely ref*cking tarded adn you should not take them seriously. Puttin that sub in a 5-8 cube box would really just make the sub flutter and give you absolutely no output. Putting a woofer recommended for 1 cube sealed in a 5-8 cube box would almost make the woofer act as if it were IB (or the enclosure to big for the sub to see it).

x2 on the porting idea. maybe add more power. loudness is really all in the design of the enclosure and you could actually end up doing more damage to your sub putting it in that big of an enclosure.

acold7dusta
09-09-2006, 11:55 AM
i think when the guy said 5-8 cu ft i think he meant ported, NOT sealed

ultimate157
09-09-2006, 12:49 PM
this sub can never be ported. ever. never.









ever.

skeptikal
09-09-2006, 01:02 PM
this sub can never be ported. ever. never.






ever.

well i wouldn't expect it to get any louder than it already is man.

squeak9798
09-09-2006, 01:55 PM
really man whoever told you that is completely ref*cking tarded adn you should not take them seriously. Puttin that sub in a 5-8 cube box would really just make the sub flutter and give you absolutely no output. Putting a woofer recommended for 1 cube sealed in a 5-8 cube box would almost make the woofer act as if it were IB (or the enclosure to big for the sub to see it).

Vb = Vas/(qtc/qts)^2-1

Vb = 8.27/(.707/.42)^2-1 = 4.51cuft

;)

Likewise, in that 4.51cuft enclosure, the F3 would be 26.9hz...extremely low for car audio, given the transfer function (cabin gain) of the vehicle is going to be adding tremendously to the output at those low frequencies. So yeah..in a car, it should be a "low end monster" in a Qtc .707 alignment.


It sounds to me, given your description, that the enclosure you are using is simply too small. Larger enclosure will have less peak output, but more output at lower frequencies as it will have a lower F3. This will in turn give you the low frequency extension that you are needing. And with the increased compliance of the larger enclosure, it will allow for more output at higher frequencies with the same level of power. With too small of an enclosure, the compliance decreases (inversely; "stiffness" increases), hence more power is necessary for a given output level. This could also be a culprit in the lack output you are experiencing.


My advice; Try a bigger enclosure. If you can fit it, build an enclosure of ~4.5cuft and try it out. From then you can begin adding filler to the enclosure to drop the net volume (like scraps of wood) to find the enclosure volume that best suits your goals.

squeak9798
09-09-2006, 01:59 PM
If you want to learn more about how enclosure volume affects the response of the enclosure, do a search. Myself and others have extensively described the relationship.

ultimate157
09-09-2006, 02:48 PM
If you want to learn more about how enclosure volume affects the response of the enclosure, do a search. Myself and others have extensively described the relationship.

Sweet, thanks for the re-assurance. I've got a Jeep cherokee cargo area to play with, so volume is no problem ;)

I was just dissapointed that a 12" running on 700w is much quieter at most frequencys than my previous 100w x 2 10" $70 subs.

I guess a 4 cubic foot box is in order :naughty:

edit: the peak is between 35 and 45 hz. those frequencies are very loud. Anything below is barely audible. anything above my 6.5's, even with the crossover slope, is louder.

ultimate157
09-10-2006, 12:17 AM
If I put my sub in a 4.5 cube sealed, I can only give my woofer 700w RMS as it is a single 4 ohm VC and I'm running a 2000D.

Is there going to be any problem of physical damage with an enclosure this big?

squeak9798
09-10-2006, 12:20 AM
Keep in mind that though the enclosure is "big" in physical dimensions, the subwoofer needs a large enclosure....so to the subwoofer, it's not "big".

You should be fine.

At worst, the subwoofer will let you know when it's not happy with the power.

phantom240
09-10-2006, 10:43 AM
Bottoming out IS quite loud.

ultimate157
09-11-2006, 02:56 PM
I got the 4.399^3 sealed done, nice n air tight. The stupid thing still acts like its in a bandpass enclosure. Bottom end is a little better, but still drops off after 35hz.
Top end drops off after 45hz.
I'm going to take my previous setup, two 10" pioneers, wire them to 8 ohms (drawing only 325ish watts from amps) and see if its the amplifier. I'm pretty sure its not because the SSF is set to 20ish hz, and the LPF is set to 80ish hz.

ultimate157
09-11-2006, 03:41 PM
Time to bring this to another section -- Opti isn't putting out enough power. I hooked up my old amp, 200w rms x 1 moves it more than my opti 2000D? wtf...