First I want to say Thanks in Advance to anyone who can help me with this. I don’t really understand car audio too well, so I am having a professional company online build my box for me. I hear the box is crucial to getting good bass from your system. I want to make sure I get the correct box with the right specs…since I just paid a lot of money for my sub, and it’s a very high quality sub I hear…so I would hate to see it go to waste. Here are the specs given by the company (Treo) for my particular 12 inch sub (and I only have one sub) Ported- 2.25 cu ft net, 35 sq ft vent, 18.5" long, F3=31.8Hz
–Now when I went to fill this info out on the custom box website, they never had anywhere for me to put in the 18.5 inches long for the port. I will copy and paste here what I see on the final page right before I am about to place my order for the box- Subwoofer Information
Subwoofer Size: 12 inches
# of Subwoofers: 1
Cutout Diameter: 11.125 inches
Mounting Depth: 6.375 inches
Enclosure Details
Port Type: Slot Port
Port Tuning: 31.8 Hz
Port Dimensions: 13.125 x 2.75 inches (Height x Width)
(port length is not displayed) NOTICE HOW IT SAYS PORT LENGTH NOT DISPLAYED?? I WAS NEVER ABLE TO ENTER IN A PORT LENGTH…so will this be ok for the sub? I don’t understand..unless the Square Inches of the port automatically determine this I would assume?
Port area: 36.09375 square inches
Number of Ports: 1
Net Internal Volume: 2.25 cubic feet
Port Volume: 0.9288 cubic feet (includes displacement of port materials)
Subwoofer Displacement: 0.2000 cubic feet per subwoofer
Total Internal Volume: 3.3788 cubic feet ($15.75 extra)
Number of Terminal Cups: 2 per subwoofer ($5.00 extra per subwoofer) NOTICE HERE I SELECTED THE OPTION FOR 2 TERMINAL CUPS…WOULD YOU RECOMMEND THIS?
Front Baffle: Dual-Layer Front Baffle - 1.5" Thick ($15.00 extra per subwoofer) AND HERE I SELECTED THE EXTRA THICKNESS OPTION. IS THIS THE RIGHT CHOICE? OR SHOULD DO I NOT NEED THIS, OR WILL IT JUST TAKE UP MORE SPACE?
Box Dimensions: 26.5" (w) x 20.75" (d) x 14.625" (h)
So, that is basically the custom specs I put into the website, so they can design my box accordingly. I just want to make sure I get the correct box for this sub, so that is why I am asking these questions. It seems that I put everything in right. My main concern is the port length, which it never did give me any option to enter it, and it won’t display it so I don’t know how much it is. And then about the woodthickness for the extra 15.00…is is needed? Thanks again. PS- the company/website I am ordering through is called klausaudio.com It’s the first site I found that will design the custom box for you. Most sites I see just have prefab boxes.
ONE OTHER CONCERN I have that I just noticed was where it says (and I will copy/paste) ""Total Internal Volume: 3.3788 cubic feet ($15.75 extra) ""
But my concern is that the specs said I needed 2.25 cu. ft net. Why does it say 3.3788 cubic feet? I entered in 2.25 when they asked during my box creation. Maybe I am just a little too over cautious, but just want to make sure this is right and that there are no errors here.
simple questions first.
first off: the manufacturer will give you "guidelines" to follow for building boxes. Amateur installers will go by these numbers. When you get more advanced, you measure the Theile small parameters with computer software and the computer tells you the box to make for the bass you want.
in regards to the twin terminal cups, you only need one, unless you are using a dual voice coil (DVC) subwoofer. If it has only only voice coil, only get one and if need be install the second one later. To find out what type of sub you have, look for how many sets of terminals you have on your subwoofer, if you have 2 sets (2 red and 2 black bindings) then get 2 terminals on the box.
The internal box volume issue: the manufacture stipulates the box should be 2.25 NET - the net is the keyword here. Net volume is box volume minus subwoofer volume (a typical subwoofer displaces around 1 cubic foot) so 3.37-1=2.37 - this is close enough. For a ported box, as long as your specs are within 10% it will still sound great.
For the ported issue: there are different ways to tune a subwoofer. It doesnt really matter if you use vents or ports, it just changes the size of them. The box building company will have programs that tell them if they build a box "x" big and you want to have "y" tuning, they will have to build a port or vent "z" big. There is not real need to tell them how to build the vent, only what tuning you want.
Baffle - 1.5" think - wow - how many watts are you feeding this thing? I have built a 18" 750 watt home theater monster tuned to 23 hz and I only used 3/4" and I never have problems and its enough to knock pictures off the wall - literally. On the other side, the less the box vibrates the more volume you get, will your ear notice a difference at normal listening levels - no - it might make a difference at 140 db plus, but then your an idiot for driving with it that loud. Also for adding weight you cut down on acceleration times and fuel mileage
Not sure if you already paid for the box, but you could prob do this your self for $100 or get someone to build it for you within your city for $200. The latter way is great - your saving huge money and giving someone in your community some cash! Think about it, you know how big your box has to be, you know how big your port has to be, as long as you can cut straight lines, glue, use a nail gun (optional) and a caulking gun, your set. And you can make a box you build your self look WAY nicer than a boring black carpeted box. I have custom built home theater speakers that sound and look as good (i used 3/4 mdf but the front has cherry stained mdf/veneer wood) as speakers worth $3000 but I did it all for $1200.
The head unit is the most important component in the stereo, closely followed by the amps, then boxes then subwoofer. So if your going through all of this to get optimized sound, dont get a $150 deck and a $100 amp - get like a $300 deck and a $200 amp
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