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Discussion Starter #1 (Edited)
Hello,

I designed a cab that fits in the back of the Xcab, lets the seats all the way back, and still allows you to put crap back there :) The jumpseat is blocked though. But the jack and toolbox are both intact.

AAAAAAANYWAY

It has a total of 1.97 internal cubic feet. It will house 2 12" speakers and 2 6x9 speakers. I am going to run 1/2" or 1" channels in it for venting.

My problem is I need to know:

How long should the 1/2" or 1" channels be? Should it be filled (With filler material) with 2 12" speakers (At 2 Cu Ft), and what is a good cubic footage for 2 15" speakers?


oh, and check this shizzle out:

http://www.the12volt.com/caraudio/boxcalcs.asp



When I am done with it, and if it sounds good, I'll post dimesnions on it.
 

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Always Dreamin Big
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That box isn't big enough to port, you'd need more along the lines of 2 ft^3 per sub to run a ported 12. Also, you need something a lot bigger than 1/2" for a port. You don't want a port to be more than 9 times as tall as it is wide, so the biggest port you could run is 1/2" x 4.5", which is WAY small. You need a slot more like 2" x 10".
 

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Discussion Starter #3
OK. So I shouldn't port it, but if I were to port it, I'd need 2" by 10" ports, or 2 1" by 10" ports, right? So I should totally seal it to get the best sound then, like 35Hz or whatever it is.
 

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Always Dreamin Big
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Port size takes a lot of things into consideration. Box volume, tuning frequency, sub size and power, all have to be weighted in a sence to pick a port size. In a small box you need a smaller port area or else the length just gets unusable. Same goes with a very low tuned frequency. If you are tuning high, using a big box, and using subs that are real performers than you need a lot of port area.

Just an example:
If you were going for an L7 ten in an spl setup you'd probably want like 3 ft^3, tuned to like 45 hz, and a port with at least 30 in^2 of area (at least a 3x10).
If you had some old-school Oz Audio ten that you wanted to run for sound quality in a 1.75 ft^3 box, then tuning would be more like 30 hz, and a port area of 7 in^2 could do just fine (2x3.5).

So port size depends on a lot of things. At very minimal it should be 3 inches in diameter if using a ten or larger. This is a touch over 7 in^2 of port area. All out slp guys use huge ports. My friend runs 4 RE XXX 15's in a wall, his port is massive. I can't remember the exact size, but it's probably close to 24x36. I know I had no problem sliding into his box and signing my name and the date inside it :D.

But you definitly should not port 12's that have less than 1ft^3 a piece. What subs are you looking at using? By the time you take out space for the 6x9's you are going to have very little airspace, even for a sealed 12. The 6x9's are going to have to be seperated from the subs, or else you will not get a good performance from your subs (box will not behave like a true sealed box) and you'll kill your 6x9's (overexcursion from the subs pressure and ripping the surround/spider out will probably happen after cranking it just once or twice). Once you figure about .2 ft^3 for each 6x9 you are only left with around 0.8 ft^3 (before displacement) for each 12. That's way small, and there are virtually no 12's on the market that will perform to their potential in that size box. I personally would look at getting ~1.25 ft^3 per sub sealed. You'll get much better lowend extension. A sub in too small of a box rolls off high in the bass range. This means a 15 in a tiny box may sound like an 8 in a proper sized box.

If I were you I would try and design a larger box.
 

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Discussion Starter #5
I slept through algebra, what's ^? Well, to be honest, this speaker box is also going to be a table to make space of the Xcab. The point is to make it as small as possible. To also be honest, I'm using mega cheap speakers (In other words name brand speakers without the name brand), with a mega cheap amp. I have tested the amp on 4 12" speakers and it is great. The speakers are going to come when I get paid next week. So in this enclosure with these speakers and this space, do you recommend porting or filling? OR **** it, it's going to sound like shit anyway? I could make the cabinet bigger, but if it's going to bump alright, I might be happy.

This is the 12" I am probably going to use.

Designed for small, sealed, portable, and
bandpass enclosure
Saphire blue chrome plated injection cone
Rubber surround for extended durability
Black frame
Gold post
Material: polypropylene
Foam edge
One speaker per package
RMS power: 150W. Power: 300W. Size: 12"
Sensitivity: 93dB Magnet: 60oz
Voice coil: 2" Frequency: 30-3.5Hz
Dimensions: A=1 1/2" B=6 1/4" C=5 1/2"
VAS (L)/cu.ft.:259.23/9.15
Qms: 2.915
Qes: 0.232
Qts: 0.215


These are the 6x9's

Comments:
6"x9"4-WAY P.P CONE 330W
---------------------------------------------
.
SPECIFICATIONS:
One Pair/Package
2.5"Mylar dome midrange.1.5"Mylar dome
tweeter.0.5"Mylar dome type super tweeter.
Sensitivity:93 dB.Magnet:30.Voice Coil:1.5"
Frequency:45Hz-20kHz.
Dimensions:A:1.25"xB:4.75"xC:4.5")
 

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Always Dreamin Big
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So are those the Lexons, Emersons, Legacys, or what?

Ok, here we go. I would highly, highly, HIGHLY suggest you do this right and do it once. You're sound quality and output is going to SUCK. You'd be better off putting a single sub in your truck with a quality amp than that crap you are looking at. I'm sorry, but I can't stand it when I see people waste money on products like that. I would seriously watch Ebay for a good deal on like a JL Audio W-0 or a Kicker Comp VR or 100 other subs that will stomp those into the ground.

Spending a little more now will save you a lot later. Because the first time you hear someone with a well setup system you'll want to throw that setup in the trash. I believe I have heard those subs, they were some model of Legacy. The x-max is so small that you might as well run a decent 10, because it will push as much air as the pair of 12's and stay much more linear and controled while doing it.

If I were you and on a small budget with that space you have I would go with a single 12 ported. Check out www.sounddomain.com and their hot deals. There is always some good stuff there. I got my ten for $40, and it's not a junk speaker with lousy specs. Over 12 mm of x-max, a true 350 rms power handling, a suspension that is actually tight with a low mass moving structure. The insanely high VAS on the sub you are looking at shows its a heavy cone with a weak spider. It can be argued that this will not necessarily kill the speakers sound quality and transient response, but that is only true if the speaker has very strong control over the voice coil. I guarentee that a 150 rms sub that costs next to nothing does not have a high motor strength. So it will sound like poo.

And also, the ^ means "to the power". So ft^3 means to the third power, or feet cubed.
 

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Discussion Starter #7 (Edited)
So you're saying I should go with one 12, or maybe 2 10's with that box, of a high uality name brand nature.

The speakers are Lexons.. I could get a much higher rated Lexon but it wouldn't have the response or low end freuency I want.

Check this out: go to http://www.dalbani.com/CGI-BIN/LANSAWEB?WEBEVENT+LB7151A44450943E2DFB113F+M36+ENG

So you're saying none of those speakers are any good.

Is a lower VAS reading better?

SPECIFICATIONS:
Designed for use in sealed, vented, bandpass,
and Free air system
Chrome plated motor housing
Silver post with screw type terminals
Foam edge
Fully chrome plated frame
Double magnet
Double damper
Foam edge
Material: Polypropylene
One speaker per package
RMS power: 200W. Power: 400W. Size:12"
Sensitivity: 93dB Magnet: 80oz
Voice coil: 2" Frequency: 30-3.5kHz
Dimensions: A=2 1/4" B=6" C=6"
VAS (L)/cu.ft.: 97.99/1.59
Qms: 9.6653
Qes: 0.2736
Qts: 0.3261

Or even:

State-of-the-art injected aluminum cone
Chrome basket
Treated rubber surrounds
Rubber magnet boot
Bumped & vented motor structure
Aluminum voice coil
Gold posted coil
One speaker per package
RMS power: 150W. Power: 350W. Size: 12"
Senstivity: 87dB. Magnet: 50oz.
Voice coil: 2". Frequency: 25-2.5kHz
Dimensions: A=1 1/4" B=6 1/4" C=5 1/2"
VAS (L)/cu.ft.: 195/6.89
Qms: 5.5
Qes: 0.85
Qts: 0.67


I really appreciate your help. I'm still undecided but I did get the 6x9's in the mail today..
 

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Discussion Starter #8 (Edited)
I redesigned it: It now has 3.2 cubic feet. It changes nothing though It hink.

AAAAAAAAAAAAAAAAAAAACTUALLY I think I made a mistake in calculating the volume.

It might be 8.11 cubic feet.

The main section is 45x14x10.5, with a smaller 6x6x10.5 section with another small 14x6x10.5 section and .75" thick mdf. @#$%#@%@#$%!!!
 

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Always Dreamin Big
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wolfmangk said:
So you're saying I should go with one 12, or maybe 2 10's with that box, of a high uality name brand nature.
YES!

The speakers are Lexons.. I could get a much higher rated Lexon but it wouldn't have the response or low end freuency I want.
Those numbers mean absolutly nothing! Take the frequncy responce and SPL numbers from the specs and ignore them. I can guarentee that in a box neither of those subs will play down to 30 hz with the output you want. Usually a sealed box will fall off around 40-50 hz. Sure it plays the lower stuff, but not as loud as the higher bass. If I am looking at subs I don't care if they say the frequency range is 15-8,000 hz or 40-400 hz, the box design, amount of power, and vehicles acoustical properties decide that more than anything.
 

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Always Dreamin Big
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Check out Sound Domain. They still have the ten that I am running for $39.95. A pair of them can't be anymore than the 12's you are looking at, and they will really outperform them. You could port the box with the sizes you gave (as I pm'ed, comes out to roughly 1.25 ft^3 per sub). You'd get louder and sound so much better. Plus porting and tuning low will improve the low end of the system sooo much over a sealed box. My music has so much more output in the 30-50 Hz range when ported over the sealed box.
 

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Discussion Starter #11 (Edited)
OK. If I can find one good 12 for a good price (Less than say, 50 or 60 bucks?) I might just do that. I take it two good 10's are better anyway, though. Maybe I can buy them one at a time, one every paycheck or something.


Actually, now with all this information you have provided, it's clear I only have one choice. The only problem is, won't all that glue make for some toxic smoke when I throw the entire ****ing thing in the fireplace?
 
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