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Subwoofer and Subwoofer Encloser questions.


MaStaMooN

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My sub is a 5 year old Eclipse Aluminum 12" 88120, 500w RMS (i think). From the little bit of info i can find on the sub, it wants between 1 and 1.5 cuft of airspace for a sealed box.

 

My amp is a Phoenix Gold zx600ti (over 600w RMS).

 

Im trying to find a sub box for this sub that will fit behind the back seat on the right. Cant find a square box that fits locally, but found a 'wedge', that fits how I like, but according to the sound shop, has .9 cuft of airspace.

 

I listen to mostly rock type music, but do listen to some 'good' rap/hiphop now and then so I want it to perform well for both. Not looking for massive SPL obviously, but not looking for pure SQ.

 

So I got 2 questions. If a sub manufacturer says its sub performs best with a certain size box... is that size they list the airspace left AFTER the sub is installed or without the sub?

 

Second, will I be doing this sub an injustice fitting it in a box .1cuft smaller than "recommend" size box. This also will depend on the answer to my first question... if they want 1 cuft after the sub is installed.. than this box will not work at all.. it will be way to small.

 

Sadly this box at the shop is all they carry that will fit and they want 50 bucks for it. They said they could build me something that will be the right size and fit where I want, for " a couple hundred bucks"... but id just do a wickedCAS box for that price. Another shop told me around 150 for a built box... which I think it still to much for my needs. But if its between having a sub or not, I might have to go that route... if that wedge will not work.

 

Help me out here, what do you guys think?

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I'm using an Eclipse Aluminum 8122 12", 500w RMS in a Wicked CAS box on the passenger side. As far as calculating the volume, have you tried a calculator like one of these?

http://www.carstereo.com/help/Articles.cfm?id=26

I did calculations and a good volume for be was around .6-.8ft^3. The Wicked CAS boxes are .75ft^3, so it ended up being just about right.

 

I would guess that the manufacturer recommended volume would be the volume with the sub, so you would have to compensate, but I honestly don't think the sub volume would make that big of a difference unless you're a super audiophile.

 

For the space issue, a way to fake a larger volume is using Poly-Fill or similar material. Having a box that is too small will reduce efficiency of the sub and will probably raise the natural frequency of the box, making it not bump as low as you want.

 

Hope this helps.

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I've been in car audio a long time and used to compete. I used have a WRX with a 12" Infinity perfect sub in a 1 ft box and it sounded okay but not up to my standards. Finally got a box with the right dimensions (1.5 cf) and it really made a difference. Low frequency extension turned excellent. Moral of the story is go with recommended size not smaller. A liitle larger works well too.

 

I recommend the wicked box too but you will have to drop to a 10 inch sub. The Jl version is very good but expensive.

 

You will not get very good bass from the location you are trying to do. Ive tried it before without much success (then again I am more meticulous than most)

 

Airspace requirements already take into account the basket, coils , magnet.

 

Polyfill may fool a sub to some degree but will never make up for proper airspace. I read sometime ago realisticly you can increase the space that bway not much more than .25 cf. In fact overdampening affects sound quality adversely.

 

I'm headed the wicked box direction with a custom Image dynamics 10" sub for my LGT wagon. The box fits great and is reasonable. You should look into that direction.

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The specs for my sub are as follows:

 

FS 28Hz

Qts .29

DCR 3.1ohm

Vas 2.68 cuft

Xmax 1.17"

 

putting those numbers in and picking a Qtc in the range of .9 to 1.2 as the calculator suggests, shows the Vb equalling between .31 ft^3 and .166 ft^3.

 

So am I reading this right or just not understanding the output... a .9 ft^3 box would be TOO BIG for this sub with the specs I have?

 

Then again, if it is correct, if the box is supposed to be .3 ft^3 and I have a .9 ft^3 box, subtract the size of the sub when installed.. might come close to that .3 ft^3?

 

I dont think these seems right, but I know very little about the science of car audio.

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And according to the specs I can find for the 8122, entering the numbers in that calculator gave me a range of .767 ft^3 and 1.474 ft^3

 

So i must be missing something or using way wrong numbers.. I wish eclipse would publish their numbers in an easy to find place and also mark their damn subs so you know what you got. I got this thing so many years ago, it might not be an 88120.. could be the same as your sub for all I know. And seeing the range of box sizes your's should use.. makes me think I have the wrong sub.. haha

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Id love to do a wickedCAS box, but I just dont have 300 bucks to spend on a box.. and would like to use this sub so I dont have to spend even more cash on a new sub ontop of a box.

 

I've been in car audio a long time and used to compete. I used have a WRX with a 12" Infinity perfect sub in a 1 ft box and it sounded okay but not up to my standards. Finally got a box with the right dimensions (1.5 cf) and it really made a difference. Low frequency extension turned excellent. Moral of the story is go with recommended size not smaller. A liitle larger works well too.

 

I recommend the wicked box too but you will have to drop to a 10 inch sub. The Jl version is very good but expensive.

 

You will not get very good bass from the location you are trying to do. Ive tried it before without much success (then again I am more meticulous than most)

 

Airspace requirements already take into account the basket, coils , magnet.

 

Polyfill may fool a sub to some degree but will never make up for proper airspace. I read sometime ago realisticly you can increase the space that bway not much more than .25 cf. In fact overdampening affects sound quality adversely.

 

I'm headed the wicked box direction with a custom Image dynamics 10" sub for my LGT wagon. The box fits great and is reasonable. You should look into that direction.

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http://www.freewebz.com/eclipseb2bs/index.htm

 

Almost positive I have an 88120.4 now looking at this dated site.. there is a link to the eclipse 2001 catalog.. and I think my speaker is in there... .9 seems to be a good size box for it actually according to eclipse themselves..

 

They give a few options.

 

.5 = competition

.85 = boomy

1.5 = NatBass

2.0 = ExtBass

 

So I think im gonna go with the box in question and see how it works.. the guy at the shop says I can bring it back for store credit so shouldt be too big of a risk.

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As for the calculations, the recommended box size they give you is what the interior volume of the box should be, they already accounted for the speaker's displacement.

 

Here is what I did to solve my trunk space issues...

 

http://i11.photobucket.com/albums/a165/basmoq/Subaru/0502081558.jpg

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