Joe X

So before anything I would like to know your situation, do you have a working system that is not performing well and you want to improve it? If the sub has currently an enclosure, do you have specs? Do you have any pics of your system you would like to share?

So here is a second suggestion, power: to sub rated, amp subsonic filter to 28Hz, minimum port clearance 9 cm, figure is just an assembly guide: NOTE: Tuning down to 34Hz and F3 of 26Hz, will be adequate for low tuned, music, net volume up to 4 cubic feet. NOTE: If building outside you need to build a cardboard dummy box to test fit in it's way inside.

I take note of your new maximum dimensions but I would like to know brand and model of your sub, amp, head unit, other components you may have like equalizer, DSP or any other device you may have. Also how is your electrical spec, battery, alternator, wiring, etc. Also check this video on what is cliipping and why you need to avoid it, it's meant to be short and simple, I will post other links later:

Box wise you do a larger internal volume to get more output with less power, in your case going to 4 cubic feet net should be doable but I already made the box as big as your available space allows. Tuning should be as low as the music you play needs but not lower, I think if you generally do not play low tuned music like rap you are better off with the higher tuning you chose. To avoid damage to your sub you should be aware of clipping, specially with modern full bridge amplifiers which if not used properly can clip very easily. Clipping is one sure way to destroy a sub. If you are not familiar with this let me know let me know and I will post you some links so that you know how to avoid it.

Here are the plots for the above box for the D4 version of the sub: Projected in-car frequency response: Cone displacement: Vent airspeed: Should sound pretty good but since you asked for higher tuning your -3db half power frequency is about 31 Hz, so not too great for low tuned stuff like rap.

So here is a suggestion, power: to sub rated, amp subsonic filter to 28Hz, minimum port clearance 9 cm, figure is just an assembly guide: NOTE: If building outside you need to build a cardboard dummy box to test fit in it's way inside.

It feels surrealistic to read that you want dual alternators and 4800 Watt RMS worth of amplifiers to drive four 300 watt subwoofers. Am I missing something? If those subs were Sundown X v3 then it would barely make sense.

What are the maximum dimensions for a box?

Double vs triple.

Here are my 2 cents, take the time to answer at least some of the questions we asked you if you seriously are looking for help.

You just resurrected a 14 year old thread, pretty awesome. Is this a new issue or you are just finishing a new install?

That port is a joke as you describe it, you should list your full box design and pics of everything, your subs are kind of entry level too. Also relax a bit please, one thing at a time. and a lot of pics.

Thanks for sharing your work.

This was better in the enclosures section I think, Do a box sub / port up to sundown specs to avoid rattle.

Give unclipped 750W RMS to this sub and it will work without issues if your box is properly designed, NEVER forget to engage your amp's subsonic filter to 28-30Hz.

Yes, the pic is just an assembly guide, the extension is so small that you could just not do it.

Can be done like this, subs /port firing forwards/backwards, power: to subs rated: 45s are done as follows:

The BRZ1200 has an output to feed a second amp so you can do that. You will need to gain match though.

I would setup the software for ported.

If you are looking to save space then yes at least two 8"s, two 10s will give you about 43% of extra cone area and will only cost you about 0.8 cubes of extra of net volume. Depends on your goals.

You have space for 12s back there, I wouldn't do 8s more so if you are thinking of upgrading later.

Fix the black on dark grey man, on your question you don't mention the vehicle, power, don't provide a sketch of your plan, and you are using a really inaccurate calculator... welcome to SMD!

So here is a suggestion to 750W RMS for the SA-8v2, depending on your specific vehicle you may probably want different port/sub aimings: Enclosure Specifications: Fb = 34.5 Hz Vb = 0.66 ft^3 External Height = 9.5 in External Width = 21.25 in External Depth = 13.25 in Port Width = 1 3/8 in Cut Sheet List: * All Dimensions in Inches. * Wood Thickness is 3/4 for all Parts. External Enclosure Parts: Front & Back = 21 1/4 x 9 1/2 Left & Right Sides = 11 3/4 x 8 Top & Bottom = 21 1/4 x 11 3/4 L Port Internal Assembly Parts: Front to Back = 10 3/8 x 8 Extension = 16 1/4 x 8 Extension 2 = 3 1/8 x 8 Assembly guide (generic dimensions): Important notes: - Setting your amp subsonic filter to 28Hz is suggested.

Most car audio speakers are designed to work on a infinite baffle setting so if you box them try to make the box on the large side to get the most from them. Other than that they will work fine wired in series as you say.

Here is a suggestion, 2K RMS limit and had to go to 15.5H hope you can fit that : Enclosure Specifications: Fb = 33 Hz Vb = 3 ft^3 External Height = 15.5 in External Width = 33.5 in External Depth = 19 in Port Width = 3 3/4 in Cut Sheet List: * All Dimensions in Inches. * Wood Thickness is 3/4 for all Parts. External Enclosure Parts: 2 x Front & Back (3 parts) = 33 1/2 x 15 1/2 Left & Right Sides = 16 3/4 x 14 Top & Bottom = 33 1/2 x 16 3/4 L Port Internal Assembly Parts: Front to Back = 13 x 14 Extension = 16 1/2 x 14 Assembly guide (generic dimensions): Subsonic filter to 27 Hz. Let me know any questions.