Some advice on building box or two - Audio & Electronics Forum

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Some advice on building box or two
Sunday, January 11, 2009 9:36 AM
I have 2 12" Alpine SWR-1240D subwoofers. Right now I have them hooked up to a Bassworx 500watt RMS class D Amp at 2 ohms. They seem to pound pretty good but when the trunk is open I was expecting more air to be pushed towards from the subs. they don't seem to pound as great as I thought they would. Right now they're in the same box side by side sharing the same chamber.

How would you guys have these setup in your cars? I'm not buying new equipment, I just want some new box ideas that will get me better bass and maybe cleaner. but the thump is what i'm looking for more.



1/4 Mile ET 15.2579 at 89.97mph

Re: Some advice on building box or two
Sunday, January 11, 2009 9:59 AM
I like closed boxs. Completely sealed. Sounds cleanest in my opinion.



Re: Some advice on building box or two
Sunday, January 11, 2009 12:22 PM
when you open the trunk, it will naturally not be as loud as with teh trunk shut .....


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Re: Some advice on building box or two
Sunday, January 11, 2009 12:28 PM
unless the box is well built. then there should be no difference.





Re: Some advice on building box or two
Sunday, January 11, 2009 5:42 PM
Well, you have to really decide what you want first. I've built a few boxes, heh, and I'll tell you that side by side sharing the same air is gonna sound like junk. Two sealed boxes of optimal airspace are gonna improve clarity, and volume. Two ported boxes are gonna give you less clarity than sealed (still more than your current setup) and more volume than your current box, or two sealed ones.

If you've never done it before, building a sealed box is a pain. A good generator will give you dims, but paper and real life are usually a little different lol. You'd have to tune alot more with a ported, but if you're looking for volume it's the way to go. If you want more pound and an easier build, then go sealed.

Bottom line, you just have to decide how much time and effort (and MDF) you wanna put into this Hope this helps!


There's a thin line to be crossed, when the upgrades to your vehicle increase your chance to get tickets by an amount exponential enough to stop worrying and build the fastest, loudest car you can.
Re: Some advice on building box or two
Sunday, January 11, 2009 6:15 PM
Hey i'm heading down to MI on thursday, think you could have two sealed boxes built by then? lol jk

Quote:

If you've never done it before, building a sealed box is a pain.


I'm going to assume you meant building a ported box is pain? When building a sealed enclosure should I pay close attention to what alpine recommends for the specs of the box for my subs? or is there another guideline to follow. If anyone has any trustworthy links on how to find the right size of box to make, aswell on how to properly make a box I'd be more than happy to read-up on it. I would search for it myself but I know there a lot of mis-information out there and I don't want to put alot of time buidling a box thats built wrong.



1/4 Mile ET 15.2579 at 89.97mph
Re: Some advice on building box or two
Sunday, January 11, 2009 8:18 PM
definatly follow what the manufacturer says if you dont have any experience designing sub boxes. but a ported box is the way to go. i could see if i can design one for you but by no means am i a professional. i just know enough to get by.

ill work on it tomarro and i should have a print for you as well.





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Re: Some advice on building box or two
Sunday, January 11, 2009 8:31 PM
That'd be awesome man, I appreciate it.



1/4 Mile ET 15.2579 at 89.97mph
Re: Some advice on building box or two
Monday, January 12, 2009 9:51 AM
15 tall x30 wide x19 deep. Your front piece cut will be 13.5 x 26 1/4. You'll want a 3 inch port, 15 inches long, and 13.5 inches high. This will give you 3.8ish cubic feet, port tuned to just about 35 hertz.

As for output, ported boxes, if built properly, are louder, just as clean, and give more output than a sealed box.



Re: Some advice on building box or two
Monday, January 12, 2009 10:28 AM
Lol, I sounded dumb. I was tired, worked 13 hours yesterday /yawn! Building a ported box is definitely harder than sealed, but still doable as long as you take your time. Look up your sub's Owner's Manual on alpine's website if they offer that. Follow that guideline and you'll be set


There's a thin line to be crossed, when the upgrades to your vehicle increase your chance to get tickets by an amount exponential enough to stop worrying and build the fastest, loudest car you can.
Re: Some advice on building box or two
Monday, January 12, 2009 2:58 PM
30" wide? for a single sub box or a dual?



1/4 Mile ET 15.2579 at 89.97mph

Re: Some advice on building box or two
Monday, January 12, 2009 3:32 PM
do you want to use both or just one?





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Re: Some advice on building box or two
Monday, January 12, 2009 3:42 PM
also could you post a link to the subwoofers specs? all i can find (after about 10 min of searching) is the displacment .071 cu ft (if its wrong let me know)





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Re: Some advice on building box or two
Monday, January 12, 2009 4:58 PM
Lanman31337 - Cavfire wrote:15 tall x30 wide x19 deep. Your front piece cut will be 13.5 x 26 1/4. You'll want a 3 inch port, 15 inches long, and 13.5 inches high. This will give you 3.8ish cubic feet, port tuned to just about 35 hertz.

As for output, ported boxes, if built properly, are louder, just as clean, and give more output than a sealed box.


i hope that was just for one type r i used a calculator and got way different number than you got. for 2 12"s you need around 69+^2 in of port and that ends up being 39.5" long. but i dont know the specs of the 1240D type r compared to the new type r. basically just need the xmax





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Re: Some advice on building box or two
Monday, January 12, 2009 5:00 PM
edit it needs to be 45" long thats with 3 cu ft of airspace





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Re: Some advice on building box or two
Monday, January 12, 2009 7:37 PM
I plan on using both, because I think the RMS of one is only 300watts and my 500 watt rms amp would probably kill it. so is that 45" for both?

and what does this mean "69+^2" ?



1/4 Mile ET 15.2579 at 89.97mph
Re: Some advice on building box or two
Monday, January 12, 2009 7:58 PM
I can't seem to find much on specs, just that it's 1000W Peak, 300W RMS and 24Hz-2kHz Frequency Response. Can't seem to find a spec sheet or anything to that effect.




1/4 Mile ET 15.2579 at 89.97mph
Re: Some advice on building box or two
Monday, January 12, 2009 11:39 PM
Just to cover one thing in your previous 2 posts....

1. A 12" Alpine Type-R sub should have an RMS power handling of 500 watts.
2. You are not going to "destroy" them by having more power on hand than you need. You could have a god damn 3000 watt amps going to a single Type-R and not blow it if you know how to tune and use what you need and have properly.
Ever heard people say the term "head room" referring to amps? Basically, having extra power on tap allows your amp to supply the power easier and letting your subs get their full power that they can handle cleanly and easily. If you are running 2 Type-R's and only have a single amp that puts out 500 Watts RMS, that amp is going to be struggling when you try and get everything out of those subs. You will clip the @!#$ out of the signal, or just be under powering them and not get their full potential and be disappointed. After building a proper box to the subs specs, I would also look into upgrading to a bigger and better amp. Just a little piece of advice that no one else has really touched on in this thread yet. Figure it is a little food for thought.


On the other hand....you have other fingers.

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Re: Some advice on building box or two
Tuesday, January 13, 2009 4:54 AM
Cold Air wrote:I plan on using both, because I think the RMS of one is only 300watts and my 500 watt rms amp would probably kill it. so is that 45" for both?

and what does this mean "69+^2" ?


it means 69 and up square inches of port area. but i made a box but never gopt around to the print of it. but its huge lol. it is 31.5 wide x 24.25 deep x 15 tall im not sure if you could get that in your trunk or not. but i would go with what jl said upgrade an amp or just run one sub.

and for the spec sheet do you have the owners manual?





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Re: Some advice on building box or two
Tuesday, January 13, 2009 7:39 AM
Thanks Anton and JL the help is appreciated.

JLAudioCavalier wrote:Just to cover one thing in your previous 2 posts....

1. A 12" Alpine Type-R sub should have an RMS power handling of 500 watts.
2. You are not going to "destroy" them by having more power on hand than you need. You could have a god damn 3000 watt amps going to a single Type-R and not blow it if you know how to tune and use what you need and have properly.
Ever heard people say the term "head room" referring to amps? Basically, having extra power on tap allows your amp to supply the power easier and letting your subs get their full power that they can handle cleanly and easily. If you are running 2 Type-R's and only have a single amp that puts out 500 Watts RMS, that amp is going to be struggling when you try and get everything out of those subs. You will clip the @!#$ out of the signal, or just be under powering them and not get their full potential and be disappointed. After building a proper box to the subs specs, I would also look into upgrading to a bigger and better amp. Just a little piece of advice that no one else has really touched on in this thread yet. Figure it is a little food for thought.


My type Rs are manufactured in '02 or '03 and every website I've been able to find information on about these subs say they are 300 watt rms 1000 peak. I think the model of 12" type R after mine is when they bumped it up to 500 watt rms. Knowing alpine though these subs are probably good for 380-420watts rms, since they under rate almost every one of their products.

As for the tuning I have no experience there. The only thing I know so far is the sticky in this forum about using a voltmeter on the speaker terminals to tune.

I'm going to see how much I can sell a couple amps for and upgrade to something better.
Any suggestions would be nice. and I'm not looking to buy a an expensive amp, so it doesn't have to be the newest/best on the market. I'd be happy with a 5 year old amp thats up for the job.

Also I would I tune an over powered amp properly? I'm not really interested in blowing my subs. I know if they clip I'll turn the gain down but I'm pretty sure theres clipping you can't really hear too right?



1/4 Mile ET 15.2579 at 89.97mph
Re: Some advice on building box or two
Tuesday, January 13, 2009 8:21 AM
Anton Miller wrote:
Lanman31337 - Cavfire wrote:15 tall x30 wide x19 deep. Your front piece cut will be 13.5 x 26 1/4. You'll want a 3 inch port, 15 inches long, and 13.5 inches high. This will give you 3.8ish cubic feet, port tuned to just about 35 hertz.

As for output, ported boxes, if built properly, are louder, just as clean, and give more output than a sealed box.


i hope that was just for one type r i used a calculator and got way different number than you got. for 2 12"s you need around 69+^2 in of port and that ends up being 39.5" long. but i dont know the specs of the 1240D type r compared to the new type r. basically just need the xmax


Hi, you need to put your calculator away. Not working for you. 13.5 x 3 inch = 40.5 square inches of port. Now with that, box is just about 4 cubic feet, and the reason the box is big is to accomodate for the port and sub displacement, which will bring it down to approx. 1.8 cubic feet/sub.




Re: Some advice on building box or two
Tuesday, January 13, 2009 10:13 AM
Using a voltmeter is the easiest way to tune your subs. And trust your ears for the most part. Distorted subs sound like dirt. I'm running 1500 WRMS to 1000 WRMS of speakers, I've had no problems, and my subs sound loud and clear. And not to thread jack, but they just rattled the rear window in my vert from it's top seal. My car is chilly now


There's a thin line to be crossed, when the upgrades to your vehicle increase your chance to get tickets by an amount exponential enough to stop worrying and build the fastest, loudest car you can.
Re: Some advice on building box or two
Tuesday, January 13, 2009 1:55 PM
I just thought of this, would I be better off making a single ported box, using just one type R with my 500 watt amp?


and thanks JB



1/4 Mile ET 15.2579 at 89.97mph
Re: Some advice on building box or two
Tuesday, January 13, 2009 3:35 PM
Lanman31337 - Cavfire wrote:
Anton Miller wrote:
Lanman31337 - Cavfire wrote:15 tall x30 wide x19 deep. Your front piece cut will be 13.5 x 26 1/4. You'll want a 3 inch port, 15 inches long, and 13.5 inches high. This will give you 3.8ish cubic feet, port tuned to just about 35 hertz.

As for output, ported boxes, if built properly, are louder, just as clean, and give more output than a sealed box.


i hope that was just for one type r i used a calculator and got way different number than you got. for 2 12"s you need around 69+^2 in of port and that ends up being 39.5" long. but i dont know the specs of the 1240D type r compared to the new type r. basically just need the xmax


Hi, you need to put your calculator away. Not working for you. 13.5 x 3 inch = 40.5 square inches of port. Now with that, box is just about 4 cubic feet, and the reason the box is big is to accomodate for the port and sub displacement, which will bring it down to approx. 1.8 cubic feet/sub.


well your not tuning the box correctly then
port calc

i use this calculator and it hasnt fail me for my box or a couple others ive done for friends. if you put in 2 12's with a xmax of 18 and tuned to 35 hertz youll get a MINIMUM of 69^2" of port. the you bring that info down to bottom level. with i figured a 13.5 x 5.25 port give you 70.875^2 inches (meets requirments) type that in and i used 3 cu ft and it gave me a length of 42.4. yes i realize these number are different than the ones i gave you before but i was playing around with hertz trying to get the length down a little and something got lost in translation. however my numbers are considerable different from yours. thats all i was saying. i trust my port calculator.





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Re: Some advice on building box or two
Tuesday, January 13, 2009 3:48 PM
Just use this ported box calculator its the easiest.
Ported Encloure Calc.
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