box building online calculator???

[caddyon20s 0]

thanks man u are completly correct. now is there a big difference between a 3 and a 4 cu ft box??? my finished box is 3 cu ft now, i was wanting to get as close as 4 cu ft as posible but now i only got 3 cuf ft per chamber, is there a big difference?? i see everyone wants to make this huge boxes especialy for the btls is the a good for a big box.

HOW MUCH IS MDF GOOD?????

There is quite a difference between 3 cubic feet and 4 cubic feet. Generally speaking, the smaller the enclosure is, the less efficient it becomes and the more low frequency performance you give up. Going from 4 cubes to 3 cubes is quite a big difference, especially for 15" subs. Also, it becomes harder to tune the port to a low frequency: if we assume the same cross sectional area of the port, a longer length is required to achieve the same tuning as the enclosure becomes smaller.

Not sure exactly what you're asking with the second question, but MDF is not particularly expensive. You can get whole 4' x 8' sheets of 3/4" MDF for less than $20, and that would certainly be a step in the right direction.

OK THANKS MAN, well my box is now 3 cu ft do u think that is enough for a fi bl15??? or should i make my box to 4 cu ft thanks for ur help.

[///M5 2,833]

I'd honestly like to see proof that MDF is that much more superior to fine particle board. I find it hard to believe that you would hear any difference. Someone mentioned it flexing which OK if your an SPL monger with a really wanging woofer and a box the size of a house OK. Normal daily boxes won't be large enough for the mechanical inferiority to rear its ugly head. Now I know for all intent purposes, MDF is a better construction material, but I think you guys are splitting hairs when it comes to a daily subwoofer enclosure. I'd like to see the flex. If it is that much worse, you should be able to capture it on video.

Remind me in a month or so after I move and I will gladly measure one for you with our scanning laser vibrometer and show you the difference. I have been meaning to write up a flexing tech paper for the technical section, but until I have a garage back I can't whack out any enclosures. The difference is huge. If you think we are splitting hairs I encourage you to go onto a home audio website and look at one of their sub enclosures, huge baffles and TONS of bracing.

I already admitted huge enclosures will see this problem I am talking most sane daily driver boxes in vehicles, which now that I look, the OPs may not fit this category. BTW I have always used MDF just for peace of mind. I have had friends with single 12" tuned enclosures made from fine particle board and I seen no flex difference with the eye. When an enclosure reaches a certain size then flex will come and the integrity of the material becomes increasingly important. Even MDF is gonna flex at certain lengths. Which is the reason for so much bracing in home enclosures. I'd be very interested in the reading though if you ever do get that chance to do the testing. Sounds interesting. Until then, I will continue to use MDF to avoid TCAB style flames

You missed applied my word huge, I was referring to huge baffles and probably should have used the word thick. With a 15" BL you should be running at minimum a 1.5" baffle IMO, I personally would probably run a 2.25" with a TON of bracing. Of course, the BL period is not for me.

By the way, "not seeing" flexing is a really funny statement. Your eyes (everyones) suck at this sort of thing and couldn't see it even if it is grossly moving. You have to realize that if you box happens to have a baffle with 4x the area of your sub and moves just a little bit it will significantly alter your frequency response. In particular for frequencies that don't require your sub to move a ton. I have definitely heard enclosures where there was nearly as much sound emanating from the enclosure walls instead of the sub itself. If you want any sort of reasonable frequency response this will defeat that and sound like chit. Particle board is really weak stuff and will most definitely do this. Oh and my little Rli8 with only 250w in a 3/4" (it was temp) baffle .4cuft box was able to flex the baffle and side walls.

As to your comment about not taking advice from the board, if you have already made up your mind at what you are going to do perhaps you shouldn't be asking people on a board for advice. Pretty stupid to ask something, get an answer that is uniform from everyone responding and then ignore it. Especially when there is a lot of very well car audio educated people on this board in particular. Obviously stupid to ignore good advice in particular when you asked for it.

To the OP, since your box doesn't fit it gives you a chance to actually do it right. IMO you should try to get as much internal volume as you can get up to the manufacturers specs, I am sure it will make you happier. And if you do decide to do this with particle board again, I am with NeonR and will say don't bother updating your thread here or posting again as ignoring everyone here again is something that will not benefit the board and is better left to places with only drama and bs like caraudio.com

[caddyon20s 0]

good opinion, I AM A be making another box soon, this time is gonna be made out of mdf wood, i learned a lot here yes i thank you all for ur great help.

[johnnylemoine 0]

awesome. build that new box, dont forget bracing and /or double walling and let us know how it comes out.

[IamDeMan 0]

As to your comment about not taking advice from the board, if you have already made up your mind at what you are going to do perhaps you shouldn't be asking people on a board for advice. Pretty stupid to ask something, get an answer that is uniform from everyone responding and then ignore it. Especially when there is a lot of very well car audio educated people on this board in particular. Obviously stupid to ignore good advice in particular when you asked for it.

I am not saying to ignore advice. I am asking why not question it to get a full explanation to the why or science behind it. Understanding the why in advice is the true way to learning it. If someone can't explain the why and just regurgitate vague reason, then perhaps they really don't understand why they give the advice. I question advice to learn more not to rebel or go against.

Like I said I always use MDF. It has been drilled into my head. I just have never been shown this "difference". With the amount of people following the rule, you can't rule out it's validity, but I can still question how big of a difference it is until shown otherwise. It is certainly something that can be measured with the proper equipment. Both in terms of physical flex and by showing metered result comparisons. You can also show basically at what size enclosure MDF truly becomes necessity. It would be lengthy testing of course, but it could be done and would be quite interesting I think.

Edited August 12, 2007 by IamDeMan

[caddyon20s 0]

ok pple i have another one, go to best buy enlcosures at best buy are made of particle board, i tought of that becuase i bought one a long time ago and it was particle board, buy the way i paid 100 dollars.

[Acidburn 10]

ok pple i have another one, go to best buy enlcosures at best buy are made of particle board, i tought of that becuase i bought one a long time ago and it was particle board, buy the way i paid 100 dollars.

your point?

you got ripped off on a piece of shit box

[theabunai 3]

Best buy also recommend there 8ga kits for amps that can push 1k watts... just cause they have it doesn't make it right..

Particle wood is cheap and the retail business is all about making money... they can build it cheap sell it expensive and make money.... sure it will work, but is it the best... no same with the 8ga kit.... will it work... yes.. is it good the best thing for your system...NO

Flexing can not be seen with the naked eye unless its a large system...

I do know this though as an installer

A person came in with a box made of 3/4 particle wood....

ONE 12" MTX on a 1501 MTX amp

Said he was upset cause it sounded like chit... wanted his money back on the sub... sounded rubber band like...

The owner was able to negotiate that we make the EXACT same enclosure (since he made his to specs) with no charge and if it sounded the same we would refund the price of the sub...

We made the EXACT same box with MDF, same port length, same everything...

needless to say it sounded richer deeper and louder....

this could be a rare instance but i do know that boxes made with MDF have a different "sound" then those made with particle wood... I don't know the science behind it as i'm not a physicists but i do know that there is a reason why competitors, manufacturers, High End install shops all use MDF... Cause if there was no significant difference to particle wood I am certain they would use it....

Edited August 12, 2007 by theabunai

[crunch1 0]

hiyas, my take on box flexing is this "the less the better" why? because flexing is basically turning the enclosure into another sound source that may have negative effects on your intended sound waves. You might get lucky with the flexing and not produce cancellation waves but why risk it. I would much rather try to reduce the chance of anything interfering with something im trying to control. ps: even with the proper materials your still going to have some measurable flex, but not enough to give you problems. now for how much flex heh I took two scrap pieces of 3/4 Mdf and particle board (both were the same size and thickness) and placed then on my saw horse evenly and then placed two new 5 gallon buckets of drywall plaster on them (one on each). the particle board busted and the Mdf didn't. so I would say the Mdf would be the better choice for having less flex. heh not to scientific but its all I had laying around.

[theabunai 3]

hiyas, my take on box flexing is this "the less the better" why? because flexing is basically turning the enclosure into another sound source that may have negative effects on your intended sound waves. You might get lucky with the flexing and not produce cancellation waves but why risk it. I would much rather try to reduce the chance of anything interfering with something im trying to control. ps: even with the proper materials your still going to have some measurable flex, but not enough to give you problems. now for how much flex heh I took two scrap pieces of 3/4 Mdf and particle board (both were the same size and thickness) and placed then on my saw horse evenly and then placed two new 5 gallon buckets of drywall plaster on them (one on each). the particle board busted and the Mdf didn't. so I would say the Mdf would be the better choice for having less flex. heh not to scientific but its all I had laying around.

Wow that is a pretty good raw test crunch... I mean your right not scientific but it sure does add to the MDF is better then Particle wood Theory..

[crunch1 0]

heh ya it was quick and raw just like my women.

[caddyon20s 0]

there it is my finished work I AM A try this box first and if dont like it i have a friend that needs a box and I AM A sell it to him, I AM A try it first to see how it does if it does good i keep it if not sold. i will have videos pretty soon.

[///M5 2,833]

Let me get this straight, your trunk doesn't close but you are going to use it anyways. That is a new level of ghetto.

That box needs bracing even if it was made from real wood. That is going to be one hell of a fart cannon.

[caddyon20s 0]

one question what is the difference between tunning a subwoofer box to 30, 35 or 38 hz what is the bass like at each frequency ???

ok i know everyone is going to lough at me but i had to tell ya, after i finished my box and put it inside my caddys trunk the trunk wound not close i mean it did fit inside but i didnt pay attention to the tire moldings the moldings would not let it slide further in so i end up cutting 3 inches off the box it used to be 26 inches deep now its 23 deep i had to do my box desing again with less box volume and now i have an L shaped port, my box used to be 3.70 cu ft now its only 3, would having a smaller box effect anything??? thanks and yeah it sucks but o well life goes on thanks everyone.

i think you didnt read this but i cut 3 inches from the depth of the box now it does closes, my cu ft went down though now its only 2.95 cu ft after sub and port displacement, i will try and let you all know what happens i could not do double buffle becuase of the space in my trunk ooo well i will try it tomarrow.

[caddyon20s 0]

resuts from two different subs,,,,,,, i just finished putting both my subs and amps in and installed, and it sounds really good i dont see no bass cancelation, now my windshield shakes pretty good i like it the only problem now is my electrical system it sucks I AM A be upgrading it prety soon.

[///M5 2,833]

It is really intelligent to run an amp that pulls serious juice with insufficient electrical. I guess I shouldn't be surprised though.

[caddyon20s 0]

what could happen it the amp doesnt have enough juice from the battery and alternator????

[Acidburn 10]

what could happen it the amp doesnt have enough juice from the battery and alternator????

The amp could fry.

[caddyon20s 0]

fry??? that dont make sence,,,, ive heard an amp can fry from too much voltage but not from low voltage. Ok since I AM A be running 1800 rms i have a 140 amp alt, should i replace the alt or get a yellow battery?? im kida low on money right now so i can only do one of the two.

[ANeonRider 3]

Only shitty amps will give up the smoke with too much voltage....

Too low on the other hand is the amp killer.

[caddyon20s 0]

yes but why???? i tought if an amp doenst have enough juice to suck from it just shutts off. ok do i need an alt or a better battery??? my stock alt is 140 amps

[almond 0]

because as you're voltage drops your amps increase in order to keep the power going. amps (current draw) create heat and that's what fries the electrical components.

[bdawson72 0]

I'd look into getting some more batts.

[///M5 2,833]

I'd look into following advice when you are given it.

[lj_dudley@yahoo.com 0]

i would get a bigger alt. batts will not give u more power to your amps for very long.