Help for wall - 4 Soundstream T6-15 5k rms

[Alvy84VTS]

Hi community, I am here from Italy to ask your help for my project (Sorry for my not perfect english)

I have 4 Soundstream Tarantula T6-15 subwoofer and 2 Soundstream X3.60 amplifier (about 5000 watt total for the subwoofers).

I want to buy a wall in my car, a Citroen Saxo VTS but I have never built a big box like that before so I really need your help.

I am interested in doing hair trick but also have a "loud sound" from my subwoofer box, I hope this two things can be done by a single box! I think that having a box for hair trick don't allow me to have the loudest sound from my subwoofer but with 4 15" I think I can have loud.

Now I insert here a copy of the subwoofer's manual but there is one strange thing: I have bought two subwoofer before and after few months the other two subwoofer, same model and they are the same item but the data in the manual are different so here you will see all two manuals. I think right data are wrong because trying to simulate a box with WinISD I obtain a box of 4'000 liters With left data I obtain a better box but I am a newbie in calculating box so I ask you help for this.

I have already built the box:

These are pics of the box without the front panel:

and here a 3d rendering of the box:

In the first pic you can see that there is an "external structure" made in "soft" wood and in the second pic you can see a part of the "real box" made in 3/4 inch (0,75") MDF

Some friends tell me to do a 8x10" port but I want to ask you help because here I see that there are many car audio experts

Thanks

[FUKAZ28]

Looking good so far.

[ChevyBoy95]

you box volume is fine (~14.8 cubic ft for the guys in the US).

i would personally like a bigger port, but if it is short, 8" by 10" will work. I would prefer something bigger though.

All in all, it is decently easy to get loud with wall that is built right and sealed off. Hard to not be loud when you loose that much cabin space.

[Alvy84VTS]

What do you suggest me for the port?

As I say before I want to be able to do hairtricks

For this question I ask you to help me in calculating the correct port because I am not sure but I think I have to play low freq to obtain hairtrick, so the port should be right for low freq

Sorry for my not perfect english

[Alvy84VTS]

My friend that sometimes work in a car audio center, tell me this:

Increase the hole size for the vent to 11.5" x 9.5".

Use 25litres of bracing inside the box.

Make vent out of .75" MDF internal Width 10", Height 8" length 14.5" tune will be 25.06Hz, F3 25.07 (out of car)

Removing the vent the tuning will go up to 40.22Hz presuming a 1.5" thick baffle or 39.09Hz with a 2.25" baffle.

Do you think that these information are correct? Is 39Hz a good tune for obtain hairtrick or is it too high?

Thank you