Realistic numbers

[Jeffdachef 5,000+ posts]

instead of double layering the whole box, you can use excessive amounts of althread with big washers to brace it. I have single layered box with wooden dowels and double baffle and Have no box flex. Double layer will basically eat up his cubic feet.

 

[WhiteYota]

Ok so plotting this box out - changed the ports to 10" with 2 of them.

Flare-it gives me about 70 m/s limit on air velocity but if I plot this all out on WinISD, it shows that there is going to be around 85-90 m/s.

Is this going to create some noise or does it pretty much not apply where the ports are so big?

 

[massivespl]

Ok so plotting this box out - changed the ports to 10" with 2 of them.Flare-it gives me about 70 m/s limit on air velocity but if I plot this all out on WinISD, it shows that there is going to be around 85-90 m/s.

Is this going to create some noise or does it pretty much not apply where the ports are so big?

For two 18s I'd do a single 12" or single 10" or four 6" aero ports

 

[massivespl]

Ok so plotting this box out - changed the ports to 10" with 2 of them.Flare-it gives me about 70 m/s limit on air velocity but if I plot this all out on WinISD, it shows that there is going to be around 85-90 m/s.

Is this going to create some noise or does it pretty much not apply where the ports are so big?

check out what I got with Torres box calc

 

[WhiteYota]

Here is what I got

 

[massivespl]

U need to change your wood thickness to 1.5" an not .75.... This is for 2 18s not 2 boss audio 12s that are 250rms.. U gotta double all the walls homie. Build it right the first time.

 

[wanderer1]

what are you gonna do about the rear sagging from the weight?

 

[massivespl]

Whatever. It seems u already have your mind made up so idk why your asking questions if u have all the answers already. I've built dual 18 boxes and have seen lots of other peoples also. If u think two 10" ports is what u want, build it and fail. Don't matter to me.

 

[WhiteYota]

Whatever. It seems u already have your mind made up so idk why your asking questions if u have all the answers already. I've built dual 18 boxes and have seen lots of other peoples also. If u think two 10" ports is what u want, build it and fail. Don't matter to me.

Um wow,

I am sorry but I do know how to use a search engine - why do you think I didn't ask about if 2 x 10" ports would be ok - I asked about the air speed going through said ports.

Also, I am in NO WAY disregarding your advise and opinions but I am looking at more then just yours. Would be different if I just asked you specifically for only your opinion.

Right now I am looking at several different configurations with different port/box sizes and number of ports. There is not only one best design and each of them have advantages and disadvantages.

Anyways, thank you for the information you have provided thus far.

 

[WhiteYota]

what are you gonna do about the rear sagging from the weight?

I did find some spring overload shocks but for now wait and see just how much sag it is going to have and how much of a problem it is going to be with my kids and the box in it.

 

[wanderer1]

Might as well "bag it"

 

[WhiteYota]

Anyway as far as ports are concerned - here is what I used

39.37 * (Fb*Vd)^(1/2) = minimum port diameter

then

pi*(above number/2)^2 = minimum port area needed

I came up with 13.207 for diameter and 137 square inches of port area.

Why i went with 2 10" ports is that gives me a port area of 157, a little more then the minimum of 137.

 

[WhiteYota]

U need to change your wood thickness to 1.5" an not .75.... This is for 2 18s not 2 boss audio 12s that are 250rms.. U gotta double all the walls homie. Build it right the first time.

Ok, obviously you know more about what you are doing then me however I do want to know why a double layer would be better then using a single layer and allthread in a few places.

Here is what I got for port material - was 10$ for 10 feet so it saved me a drive to lowes/home depot (an hour and half away)

It is 10" inside diameter and the wall is 1/4". I have a 5 foot piece and 2 x 3.5 foot pieces. Figured extra would be good to have.

edit - forgot to mention that I re-measured and got a more accurate dimensions - 44 x 20 x 35(the 35 keeps it under the back window)

 

[Jeffdachef 5,000+ posts]

Whatever. It seems u already have your mind made up so idk why your asking questions if u have all the answers already. I've built dual 18 boxes and have seen lots of other peoples also. If u think two 10" ports is what u want, build it and fail. Don't matter to me.

Already said before, with excessive bracing, he does not need double layers.

 

[WhiteYota]

I would like to hear him out, maybe there is something I am missing on why he suggested using double layers. The only thing that bothered me was that he said "Whatever" without me even replying or giving his opinion on the double layers.

I have not ever build a box of this magnitude and am only going by what is said and what I read up on from this and other forums.

Maybe someday I will get this build to a point where I would do well competing with it and if double layers has some advantage to it then by all means let me know. But I am also looking at if I can achieve that goal realistically with what I have to work with for a vehicle and the space I am willing to give up at this point in time.

I have got this far into it with both my time and more money then what I originally planned so I might as well see how far I can go with it (so far I am limited to amperage I can generate where I don't see where I could put in a second alt).