vented enclousure

i got a quick question i have 2 12s in sealed box right now and they bump good but my frined has same setup same speakers weaker amp  with vented box and it sounds 2 times louder + his  bass is mutch stronger now i wonna get a vented box do i just go to the store and get any vented box bc i know these boxes has to be tunned to certain sub frequency my is 33hz-150hz can i buy a box that is tunned to 30hz? or do i have to find a box that is specifically tunned for my sub? srry im an amateur in car audio and one more thing im looking to replace my stock speakers front are 4 inch and rear are 4.5inch im looking for that bass hitting speakers what do u suggest?

What kind of 12's, vehicle, amp, wiring, head unit(radio)? If we don't know what you've got, we don't know what to tell (suggest to) you.

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2013 Kia Rio -90a alternator
DDX470HD GTO14001 GTO1014D (x3)
Big3 in 1/0G
1/0G to GTO14001

I strongly DO NOT recommend pre made vented boxes...90% of them are of really low quality.

Build it yourself or have one professionally made

If you want real answers I am the right guy to talk to.
But here is the deal. I need;
1.     Exact make, model, year for your subs.
2.     Year and model of your ride
3.     Dimensions of your current box so that I can run it through a box program and give you hard data on the differences between that box and your new design
Also I need to know if you are up to building a new box or modifying a prefab.
By the way purchasing a ready to go box is beyond a waste of your time and money

So how about it?
Are you ready for the real answer to your inquiry?

speakermakers wrote:

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If you want real answers I am the right guy to talk to.
But here is the deal. I need;
1.     Exact make, model, year for your subs.
2.     Year and model of your ride
3.     Dimensions of your current box so that I can run it through a box program and give you hard data on the differences between that box and your new design
Also I need to know if you are up to building a new box or modifying a prefab.
By the way purchasing a ready to go box is beyond a waste of your time and money

So how about it?
Are you ready for the real answer to your inquiry?

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WOW... I mean WOW!!! Most of us spend a whole BUNCH of time here, with potentially HUNDREDS (even thousands) of posts, before we come out and claim something like that... You'd better read some profiles, there, buddy. I, for one, am slightly offended... a comment like that says to me "Haemphyst has no idea what he's talking about", and you don't even know me. How do any of us know what you are or are not capable of. I bet you have all the doors in your house modified, because a standard door won't allow your HEAD through it... There's room for your head over at caraudiodomain.com, though...

Join us, sit back, listen, learn, and input... (not NECESSARILY in that order...) We all do around here.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

speakermakers, slip into this a little at a time.  Actions speak louder than words, and an accumuated body of helpful responses on this forum speaks far louder than the occasional one-hit wonder.  I wouldn't talk myself up as much as you just did, and I've been working up systems in programs for posters continuously for three years here.  You don't want to come across like that.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

::::Update::::

Speakermakers... I think you do fantastic work, I checked out your website, the one you listed in one of your other posts, and I truly am impressed with your 'glassing abilities. While it is not exactly what I would want in MY car, I do very much appreciate the effort and the end result, I'm just not that kind of "flash" guy. There is a true art to that, but PLEASE, as stevdart just said, slip into this a little bit at a time. It is one thing to be good and know it (which obviously you are and do), it is another thing to alienate people with conceit. The pictures of your glassing abilities speak VOLUMES, but glassing a box and desigining a proper box (which none of know you can do yet) are two different things.

For those interested, here is his website - posted elsewhere in the forums: www.enrichedaudio.com

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

All right here it is. Your subs are designed a little differently than most. Consequently the best box design for your subs is some what unusual, so please bare with me because I am going to explain. At the end of my explanation I will give you strait forward instructions on how to build this box so don’t worry if some of this info is a little intense.

Here are the specs on your sub

Note that the spec labeled QTS is .593
In speaker design a QTS of more than .5 is usually considered undesirable because it makes the box size huge and the sub sound sloppy. After modeling this sub on BASSBOX PRO several times it became apparent What the engineers at MTX are trying to accomplish and it became apparent to me how we can use this design abnormality to our advantage.

I believe that MTX came up with this design because it allows you to build almost any size sealed box between 1cu. Ft and 6 cubic feet and you will get almost the same effect.
Also this design is cost effective because it is not very demanding of the speakers magnet structure.

Vented boxes for this sub are another story. In the box that MTX recommends (once again props to MTXs engineers) This sub is LOUD and will sound ok in some cars (SUVs for example) but will not sound to hot in a car with a trunk of a Mercedes 300e.

How do I know this? Because every time I build a box for a car I first test, plot, and record the effect that that car has on a test sub that I have. This enables me to apply the sound that that car has on a sub to my new design before I build it. Also when a new customer (or someone that I help on the net) comes to me with the same car, I can just look it up in my database and apply that info to my next design.

In your last post you did not give me a third dimension of your current box so I have to guess at what size it is. But like I said due to the design of this sub it really makes little difference. Here is my best guess at what your subs are producing now.

This is what it sounds like out side of your car (blue line).

The pink line represents what it sounds like in your car after I have added my acoustic file of the last 300E that I built a box for (this is what your box sounds like now, not what the box I built sounds like. I don’t show that here)

Note that the out put is louder across the entire bass spectrum. This is what happens when you put a sub in any car. The two important pieces of information that we get out of this graph is that the low bass is week and the large peeks of output happen at to high of a frequency (50-80hz is to high).

Here is what I suggest for you.

“Isobaric loading”
This means that you are going to take both of your subs and mount them face to face, then you will wire the outside sub out of phase( + and – reversed) so that they both move in the same direction while playing.

Internal net volume (volume of box – port, sub structure, wood thickness that the box is made of, and any bracing) 4.0 cu. Ft
Port: 5”x5”x14.59”long rectangular (inside dimensions) and made from ¾” MDF

Here is your cut list

Out side dimensions of this box are: 14”x36”x21.25”
You can rearrange the dimensions of this box in a number of different ways and get the same volume. If you need to do that so that the box will fit in your trunk and look a certain way, that’s ok. As long as you know how to recalculate volume.

If you need some help doing that, I am here to help. Pm me and I will give you contact info so that I can give you the run down by phone if you need me to.

You can place the port any where on the box as long as it has no obstructions and it is not butted right up next to the sub. The port is constructed out of 3/4”MDF

By the way

Here is the response that you will get from your new box. The yellow line is the box that I have designed for you   

The red line is the box that MTX recommends (remember that they don’t know what kind of car you have)

This graph shows how much the speaker cone will have to move using any of these boxes. The darker area on the top is where the speaker can no longer handle the excursion.
This is important information to me because I can make the box look really good on paper, but if in reality the speaker cone wants to jump out of the basket it doesn’t really do you any good.
The graph shows very good cone excursion for all of these boxes.

And last but not least. This graph shows phase response vs. frequency. What we are looking for here is a smooth transition from left to right. The yellow line is the box that I designed for you and the red line is the MTX recommended box. Notice the ripples in the red line. This is what people hear and complain about when they say that a sub sounds sloppy and dose not hit hard. I have avoided this.

Conclusion
This box will be louder
Hit harder
Hit deeper
And sound great in your specific car

Int vol 4.0 cu. Ft
Port 5x5x14.59
No fill
Isobaric mounting

Anyone feel free to pm me on this

wow man that was some hard data u got there i know the kind of a box ur talking about let me ask u a question since u make enclousers for subs how mutch will u charge me to make me this box? im just curious but i really apriciate ur help THANK YOU

Your best bet will be to find a competent shop in your area and give them a print out of my design, and insist that they stick to the basic parameters that I have supplied for you.

Having me build your box would probably not be in your best interest due to several factors. Though I happen have an acoustic file on your car I no longer have the physical dimensions of your trunk or its opening. Don’t take this the wrong way, but I am super anal about these measurements and dot not trust any one ells to make them for me. I have been bitten by this more than once. Also I don’t know where you are located but shipping on a 4 cubic foot box is outrageous. And last but not least my schedule is quite tight.

You should expect a shop to charge you 200-400 bucks for this box.

Make sure that your box ends up with bracing inside (1”x2” Poplar struts from the face to the back works great). Make sure that the subs are mounted off to one corner of what ever side that you mount them to. And make sure that the subs them selves end up off to one side or corner of your trunk. Placing the subs near the center of the trunk might look good but you will have major acoustic cancellation.

I know that this all sounds like a lot and I wish that I could build it for you, but just remember to stick to the parameters that I have given you and it will be a rewarding experience.

ok man not a problem i appreciate the help i will get all this info to the shop and have them build me the box and what possition would u recomend in my trunk for me to place the box now i have it close to rear tail lights not all the way in the back of the trunk like ppl usualy place them

oh nvm u allready said where to place the sub THANK U :)

All the way back by the tail lights (and off to one side)is a great position. Not great for groceries, but for us enthusiasts its a small price to pay.