# 1 12": 4th order bandpass vented thru deck or ported?



## SHOToonz (Sep 18, 2007)

I recently acquired an older model Earthquake DB-12, and the tiny sealed box it's in is certainly doing it no favors. I'm debating between a moderately sized ported box tuned to around 30hz or a 4th order bandpass vented through my package shelf. The hard part about all this is I'm unable to find the Thiele-Small specs on this particular sub, so figuring out box size is gonna be somewhat difficult. Anyone got any ideas or thoughts on the matter?


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## Candisa (Sep 15, 2007)

Without T/S parameters, you cannot build a decent enclosure, so get a "Dayton Woofer Tester" to measure the parameters yourself, or ask somebody with the right equipment to do this for you, if you can't find them on the net...

Isabelle


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## danssoslow (Nov 28, 2006)

Is this the model you have?
http://www.earthquakesound.com/IMAGEJP/CAR/pdf/db_manual-short.pdf


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## SHOToonz (Sep 18, 2007)

I may have found something from Thielesmall.com. The model they have listed says for the 2004 model, and the specs listed are different than what's in the current model's manual. Anyway, they don't list all the specs, but here's what I got:

VAS: 86.13
qts: 0.6339
Fs: 23


Unfortunately, numbers have never been a strong suit of mine, so those specs may as well be written in Japanese. However, someone may be able to do somehing with em.


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## Candisa (Sep 15, 2007)

If those parameters are right, this is an IB sub...

Isabelle


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## SHOToonz (Sep 18, 2007)

danssoslow said:


> Is this the model you have?
> http://www.earthquakesound.com/IMAGEJP/CAR/pdf/db_manual-short.pdf


I've got the older model of this one. My surround isn't that big, and my dustcap is domed rather than inverted like that one.


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## Candisa (Sep 15, 2007)

Unless you're able to find somebody/a source that can tell you if those parameters you've found are right, I'd stronly advise you to (let somebody) measure the parameters.

If those parameters are right, this could be a great IB sub, even in a car with a small trunk, but if you try it and those parameters are far off, you might mechanically overpower your sub and blow it!

Isabelle


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## SHOToonz (Sep 18, 2007)

This is so damn frustrating...maybe I should just call earthquake and see if they can tell me anything. Damn eBay buys...


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## Candisa (Sep 15, 2007)

That might be a great idea, I don't know how's about the service of Earthquake and how much they care about supporting older products.
A lot of well-known brands have been sold to new owners every couple years and in pretty much each case, every time this happens, older information gets lost and service goes down.
I don't know how this is at Earthquake, but it's always worth finding it out, as long as it doesn't cost you more money than having the parameters measured up yourself...

Isabelle


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## SHOToonz (Sep 18, 2007)

the biggest problem i'm having is i don't know of a single place around here that'd have the capabilities to test the sub, and i ain't got the scratch to spend 100 on something i'll use but once.


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## Candisa (Sep 15, 2007)

Isn't there a DIY-home-audio place somewhere at a reasonable distance from where you live? Most of that places have the equipment to do this.

Isabelle


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## SHOToonz (Sep 18, 2007)

sadly, no...none that i'm aware of. i live in a tiny little positioned on the tip of Lake Michigan with no fancy stores around. i've got an email in to Earthquake hoping they'll be able to dig something out of the filing cabinet or off the back of the toilet.


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## chapdawg1971 (Mar 8, 2010)

See if you can find Audio Phil on here, he should be able to help you out.


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## SHOToonz (Sep 18, 2007)

earthquake sent me a .pdf of the manual! i'll post the specs when i get home from work.


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## Jmirage (Nov 23, 2010)

Company: Earthquake Sound
Model: dB12
Available = Yes
Last update: 11-Jan-2004
Type: Standard one-way driver
Shape: Round
Piston Type: Cone
Suspension: Santoprene surround.
Voice Coil: 2 inch polymide voice coil.
Magnet: 50 oz magnet.
Fs = 30.23 Hz
Qms = 5.353
Vas = 3.847 cu.ft
Mms = 3.581 oz
Xmax = 0.28 in
Sd = 82.15 sq.in
Qes = 0.58
Re = 4 ohms
Le = 0.78 mH
Z = 4 ohms
BL = 2.592 lb/A
Pe = 220 watts
Qts = 0.523
1-W SPL = 89.02 dB
Acoustic data: Not present

Earthquake Sound
1215 O'Brien Drive
Menlo Park, CA 94025 U.S.A.
Tel: 415-327-3003
Fax: 415-327-0179
Email: [email protected]
Website: Earthquake Sound Corp.


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## Jmirage (Nov 23, 2010)

Here are a couple of options:


Type: Vented Box
Shape: Prism, square (optimum)
Vb = 1.754 cu.ft
Fb = 40.44 Hz
QL = 6.84
F3 = 40.28 Hz
Fill = minimal
No. of Vents = 1
Vent shape = round
Vent ends = one flush
Dv = 4 in
Lv = 8.279 in









Type: Bandpass Single-Tuned Box
Shape: Prism, Bandpass
with two chambers
Chamber 1 - lower-freq.
Vb = 2.766 cu.ft
Fb = 46.21 Hz
QL = 6.619
F3 = 27.3 Hz
Fill = minimal
Chamber 2 - upper-freq.
Vb = 1.712 cu.ft
Fb = 46.21 Hz
QL = 6.849
F3 = 79.01 Hz
Fill = minimal
No. of Vents = 2
Vent shape = round
Vent ends = one flush
Dv = 4 in
Lv = 14.52 in


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## SHOToonz (Sep 18, 2007)

where the hell'd you find the T/S specs? i searched for a week tryin to find em and ended up emailing earthquake for em.


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## Jmirage (Nov 23, 2010)

SHOToonz said:


> where the hell'd you find the T/S specs? i searched for a week tryin to find em and ended up emailing earthquake for em.


In bass box pro's database.


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## SHOToonz (Sep 18, 2007)

i'll cross-reference those with the ones that were emailed to me, but the .25" of xmax seems right compared to the current model. so assuming those are correct specs, let's assume the the numbers may as well be written in japanese for all they make sense to me. which setup would be ideal for daily driving, and what dimensions are we talkin here?


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## Jmirage (Nov 23, 2010)

Well, the Vb is the volume of the box, and as to what would be the best setup, I need more information before making a accommodation.

How much power do you have?
How much space are you willing to give up?
What type of music do you listen to?
What do you have for a front stage?
What type of vehicle is it going in?
What is the most important thing to get out of your sub to you? (low, loud, flat response, accuracy)


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## SHOToonz (Sep 18, 2007)

Jmirage said:


> Well, the Vb is the volume of the box, and as to what would be the best setup, I need more information before making a accommodation.
> 
> How much power do you have? *amp is a Clarion APX1300 rated around 500rms. *
> How much space are you willing to give up? *I've got a healthy chunk of real estate between my rear strut towers I'm planning on filling up...haven't broke out the tape measure on it yet, but figure roughly 3'x2'x2'*
> ...


basically, I'm. Looking to set it up so that it's a decent performer all around without excelling in any one field. Am I asking too much?


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## Jmirage (Nov 23, 2010)

SHOToonz said:


> basically, I'm. Looking to set it up so that it's a decent performer all around without excelling in any one field. Am I asking too much?


Of course you're asking too much, you're asking for the PERFECT BOX, but there is always drawback to each design, with what you've said, I would go with the band-pass design if you're comfortable building it. It will play your rap and bass tracks with authority, get your front stage setup, put an amp on it, and cross the subs/mids over at ~70hz, and you'll have a beautiful full range. If you don't get your mids setup with an amp, and properly sealed etc, you will probably be missing some kick that this design will not compensate for.

A couple of things to keep in mind, that sub is only rated for 220 watts, and you will NOT be able to hear it distorting inside that box, so be gentle, and put the voice coil inside the vented portion so you can smell it when it gets too hot. Also, band-passes are not very tolerant of mistakes, so build it accurately as possible.

Here is your box design


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## SHOToonz (Sep 18, 2007)

well, after breaking it in gently, i've been beating the snot out of it ever since. i set the gain using various test tones from the ampguts link up top of the page there, and with the head unit set at 3/4 i started moving the gain up...no audible distortion, even with the gain maxed out. it hit hard enough to hurt, but evenafter putting on hearing protection, nothing but clean bass through several frequencies. i finally got distortion at 40hz when i turned the bass boost on. so i backed the gain down to half, bass boost off and called it good. now, as far as the box goes, i'm not a pro builder by any means...perhaps designs for a ported enclosure may be in order...


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## Jmirage (Nov 23, 2010)

Then go for the ported design, it will be good for rock, but won't play the other two genres of music you mentioned.

You really don't need to be a pro box builder, just measure 3 or 4 times before you cut , you'll have all the support you need right here!

DIY is what this forum is about, I would really give it a try if you have the tools to do it, actually, they're the same tools to build either enclosure, the bandpass will be much more impressive down low, the transients will be better in the bandpass also. This sub really belongs in either a sealed or bandpass, not so much a ported.

Did you take a look at the design? Will it fit? If you get some specific measurements that you want to work within, I can send you something that will fit perfectly. Give me 2 of the 3 measurements that you need, for example, 35" wide, 15" tall, and let me figure out how deep it will be. Also you would need to choose what type of port you want to use, round or build a square one out of wood.


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## SHOToonz (Sep 18, 2007)

As it stands, the only woodworking tool I own is a jigsaw so old Jesus may have possibly used it. My plan was to get some dimensions and go to lowe's and have a sheet of MDF cut there. Thing is, I'm not sure they can do dado cuts with their vertical saw or not. And as my brother so effectively proved the week before Christmas, men of my family should avoid spinning blades less we damn near cut every finger off our left hand. The space in my trunk that I wanna use is 36" wide by 17" tall. I gave myself an inch on height because the trunk lid's torsion bars measure 18" from the floor of the trunk, and I don't know how much they move when the trunk closes.


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## chapdawg1971 (Mar 8, 2010)

What box did you put it in? Did I miss something or did you build the box that Jmirage sent you the plans for?


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## SHOToonz (Sep 18, 2007)

i haven't built anything yet. it's still in my crappy old box.


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## Jmirage (Nov 23, 2010)

Jmirage said:


> Also you would need to choose what type of port you want to use, round or build a square one out of wood.


^^^^


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## Jmirage (Nov 23, 2010)

I'm going to assume round, since it will be easier to buy a piece of pvc than to fashion one with a jig saw . 

Here is the ported enclosure design


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## SHOToonz (Sep 18, 2007)

...i love you...


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