I need help on building a ported subwoofer box

pomz23 · 05-07-2009, 12:17 PM

I would like to build a ported subwoofer enclosure box. There subs are going to be 12" subs, not sure on the subs yet, either, use the existing 12" P1's that I have or Im going to get a pair of Kicker L7's. I know how to build a box, what I dont know is what type of configuration to make the ports in the box and what proper dimensions to build it.

treeman · 05-07-2009, 06:58 PM

This software works great and it's free

... http://www.ajdesigner.com/speaker/index.php

nalav · 05-08-2009, 04:02 AM

First step is to decide for sure which subs to use. Then a little bit of googling will come up with some very informative articles about box building and how to calculate the proper size for the box.

bes51659 · 05-08-2009, 04:50 AM

I'd like to ask; why is it that everyone that puts a sub in a car put in two speakers? Its double box volume, and only 3dB more punch at the same sound quality.

Spend more money on a single element box instead and look at dB/W.

Why is it, do you think, that there is not a single dual sub for home theater systems to buy? Is space more important in your home than in your car?

If I were to use two elements I would build a 4'th order box to acctually get better bass and not just two speakers.

Sorry for this heavy remark, but to me a dual box indicates that the builder does not know what he is doing...

pomz23 · 05-08-2009, 09:23 AM

Quote: Originally Posted by bes51659

I'd like to ask; why is it that everyone that puts a sub in a car put in two speakers? Its double box volume, and only 3dB more punch at the same sound quality.

Spend more money on a single element box instead and look at dB/W.

Why is it, do you think, that there is not a single dual sub for home theater systems to buy? Is space more important in your home than in your car?

If I were to use two elements I would build a 4'th order box to acctually get better bass and not just two speakers.

Sorry for this heavy remark, but to me a dual box indicates that the builder does not know what he is doing...

Isnt bass about moving air. and having 2 subs especially 2 L7's, moves a hell of alot of air. I dont see how 2 subs are not much of a noticeable difference.

pomz23 · 05-08-2009, 09:30 AM

Quote: Originally Posted by treeman

This software works great and it's free

... http://www.ajdesigner.com/speaker/index.php

It does not show how to build a box where the back is set on an angle. I dont want a square box.

Crinos · 05-08-2009, 09:46 AM

The whole box size to element ratio is all based on how much air the bass elements can move.
No need to build a bigger box than the elements can draw.

There's alot of tweaks and turns i bass cases.... My personal favorite is a smaler case with 4 x 8" elements where every element have it's own "air space". (four chambers that are seald of from each other).
This gives a nice and low base, and delivers a good punch if needed.
The big bonus is that the elements can move realy fast... So if you, like me, like to listen to fast music... the bass stays clean even at high BMPs

To get the idea of what I'm talking of...
Try play children of Boodoom on a 15" bass

pomz23 · 05-08-2009, 10:08 AM

I listen to everything from rap to classic rock to hard rock. So it need to sound good for all. I will build a box, If I go with 2 subs, ittl be ported and each sub will be sealed off from the other.

treeman · 05-08-2009, 12:04 PM

The program will tell you how much volume you need and you can build the box in whatever shape you want. It doesn't have to be square.

Quote: Originally Posted by pomz23

It does not show how to build a box where the back is set on an angle. I dont want a square box.

bes51659 · 05-08-2009, 03:01 PM

Quote: Originally Posted by pomz23

Isnt bass about moving air. and having 2 subs especially 2 L7's, moves a hell of alot of air. I dont see how 2 subs are not much of a noticeable difference.

It is about moving air. Two subs will shift the double amount of air. Double volume is 3dB. If you want to know how much 3dB is, let someone increase volume and say "stop" when you can tell that the volume has indeed increesed. That is 3dB.

On the other hand. Some elements will give 91dB and others 94dB per Watt and save you the space of one bass.

Apart from moving air, it is also about transient responce, dampfactor,and what kind of music you are listening too. That will dictate what box type you need. Like a bass-reflex is not very good when you have very low frequencies. There is no control of the cone below its turn over frequency, but you get better bass just over that freq.

2 more cents: why do people parallell connect elements down to 1 ohm and get fladder-bass without punch what so ever?!? And monster cables to avoid to high loss? In case you do not prefer brummm to punch.

Well, if I'm made you think and not automatically do what every body else does, I'm happy :-)

pomz23 · 05-08-2009, 03:40 PM

your talking about a few things that im clueless about. Im pretty technical but when it comes to technicality of sound and electronics related, thats out of my knowledge. Im just going with what seems logical. = 2 subs hit harder than 1. Now if you are telling me that its not worth it, than that's news to me. I listen mostly to rap with the subs, and for classic rock, I can lower the subs and between my headunit and speakers, the highs sound very good in my car. I work at a cabinet shop and I program a CNC machine, so building a box is no problem for me. I am also looking for that "wow" factor in my sub/box combo. IMO, im taking the car to shows, one sub, just looks like I didnt have the cash for a second one. I like the L7, they look sick, and from what I was told they hit excellent. Maybe someone has a recommendation for another sub that doesn't cost crazy $$. Im not looking to spend more than 150 for a sub, and Im shopping on ebay, and have found great deals so far.

Quote: Originally Posted by bes51659

It is about moving air. Two subs will shift the double amount of air. Double volume is 3dB. If you want to know how much 3dB is, let someone increase volume and say "stop" when you can tell that the volume has indeed increesed. That is 3dB.

On the other hand. Some elements will give 91dB and others 94dB per Watt and save you the space of one bass.

Apart from moving air, it is also about transient responce, dampfactor,and what kind of music you are listening too. That will dictate what box type you need. Like a bass-reflex is not very good when you have very low frequencies. There is no control of the cone below its turn over frequency, but you get better bass just over that freq.

2 more cents: why do people parallell connect elements down to 1 ohm and get fladder-bass without punch what so ever?!? And monster cables to avoid to high loss? In case you do not prefer brummm to punch.

Well, if I'm made you think and not automatically do what every body else does, I'm happy :-)

bes51659 · 05-08-2009, 05:42 PM

Technical or not, it has got something to do with what you will hear in the end.

I agree they look good. And they will do fine in quite small boxes.

Just a link to a very nice looking bandpass box Advantage is that it will still work below turnover frequency and not just move air from cone via port to reverse side of cone. But maybe you think that looks impressive? (sorry, I could not resist) They are hard to build but you seem to have all the tools. But L7's are made for ported systems I think.

Do I dear suggest that you connect them in series to an amp made for 8ohm output? Well, if you do get a low ohm amp you can still try it and connect it back and then tell me its mumbo jumbo. That goes for the rest of you guys too.

btw. What do you think hits hardest? 2x12' or 1x15' ;-) Or 2x10' / 1x12' for that matter. Someone even wanted to go 4x8'. Very interesting acctually. To my experience that will sound great but not send anything down your spine. Disagree?

thewizard · 05-08-2009, 05:50 PM

Two subs are not at all a necessity. This is coming from a guy that "used" to run multiple subs in every installation that I ever did, and it wasn't loud enough if it couldn't produce over 148db. I lived and learned the expensive way. Multiple subs are waste of space and money these days. I run a single DD9510 10" sub in a ported box driven by a true 3200 watts and a few runs of 1/0 wire. The sound quality is incredible and it will exceed 150db on the termlab, takes up very little space, and is not even visible in the truck unless I want it to be. It all depends on your box, both sound quality and SPL. I can make a piece of crap sub both sound better and be louder in a well built box then you can make a mega buck top of the line monster sub sound in a crap box.

bes51659 · 05-09-2009, 03:05 AM

I love you!

thewizard · 05-09-2009, 11:51 AM

When you decide on a sub or two post what you have chosen and we will help you design a box to make it perform well. Until you decide no design can even be considered.

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