loganberry

and if your doing 2 level 4 12"s i would do a 4 cube box AFTER displacement tuned to 32-35 hz, and im hoping your giving each 1k rms not 2 sharing it

rollingthunder

Yes. Each sub will be completely independant of the other. Divider in box, each having it's own amp.

Does 4 Cube mean 4 cubic feet? What does after displacement mean? How do you find out your tuning?

loganberry

you dont need a divider in the box, it will be easier for you if you dont, you will need to add some bracing to the box, allthread is a good canidate, 1 inch dowels, 1x1 pieces of wood, 2x4's just some examples, displacement is this, the port on the box will take up some of your cubic footage of the internal volume of the box, as whell as the subs, for example my box, my 2 level 5 15"s take up .40 cubic feet of the box combined and my port takes a cube and a half, so my box is near 10 cubic feet BEFORE displacement, but around 8 cubic feet after displacement. and yes 4 cubes means 4 cubic feet, thats if your going ported (which i suggest you do)

rollingthunder

I have to dissagree with the divider. I'm running two subs, on two amps. Without the divider one sub could be pushing the other if they are not EXACTLY set at the same level. Also if one sub blows, the other sub will lose energy pushing the other sub. It's a myth that a divider hampers the system. People who don't run dividers are simply too lazy to do it the right way........IMO Besides it's another form of a brace.....


Thanks for all your help though, I didn't get around to the e-mail today but will soon. I walked into the local audio store and after about 20 mins of conversation he agreed he would build the ported box(and tune it) and let me assist so that I can learn something..... He's charging me $100 to build the basic box and then I will take it from there with fiberglass making it look good. I will pay $100 to make sure it's tuned right.

loganberry

every single box i have used has never had a divider, ive done boxes with 2 subs, 4 subs and 8 subs all without a divider, to each there own tho, its just not needed, you wouldnt have phasing issues if you wired it up right


thats steep for a box considering 1 sheet of mdf is no more than 40 bucks, and 1 sheet is all you need, i can draw you up a box design if you would like

rollingthunder

I'm just worried about the tuning part of it really, that's why I'm willing to shell out the money because, I know you know what you are talking about, and if you say to have it at 33hz, that's what I want. I'm pretty set on the divider though just because. I can handle building the down firing box with down firing ports, but what I'm worried about is how to measure the hz, and then adjust the ports from there.


My lame attempt at a box design yesterday had side firing ports, which after research was discovered is a bad idea. That's easy enough to change especially because with the down firing ports I won't have to worry about cosmetics of the port design which I hear makes tuning a pia. I just want to make sure I leave enough air space for flow on the bottom, but I don't want to make the height of the box too high because I'd like to add a arm rest into the fiberglass at about the same height my fold down jumpseat is now. However if I need the heigth for the subs to sound right then so be it.

I can't remember what truck you have. If you have or are familiar with the super cab with a jumpseat, I'm planning on taking the jumpseat out and using everything from the dash to the front of the backseat for the subs and amp-rack.

loganberry

i have an 04 f150 fx4 scab, but i dont have a downfire box, have the professional do it this time and play around making boxes in the future, at some times its trial and error, but there is some math involved and with downfire boxes make sure the person building yours adds woofer height on the baffle plus xmax

rollingthunder

3" should be enough for that right? That's what I was thinking and then using a 2" oval cut out in the base for air movement. And by 2 inch I mean heigth the lenght will be as long as it can possibly be with out gettting rid of too much so that the weight of the box and subs is supported enough? Or should I just leave the sides completley open and just use the ends for support. Only reason I want the ovals is to limit the space my roomates 3 year old has to drop things under the box( she likes to put stuff in the ports of my home theater) . However I don't want any air noise so I might just leave in completley open on the sides? Could I put a screen on it or could a screen make noise too?

loganberry

if your going to use a screen use aluminum or some type of metal mesh thats not super confining, the more open the sub is underneath the better, have you thought about using aero ports? for your application it might be better, and for the space needed the closer you can get it to 3 inches is better, also make sure you get some good screws for the sub, drywall screws tend to break, i used 2 inch drywall screws to hold mine in at first (my baffle is 3 layers of 3/4 inch mdf) and snapped 8 of the total screws between the subs on my level 5's

hankfan79

Once again I agree with loganberry. Kenwood makes a good head unit but their woofers and amps dont have alot to be desired for. Their are tons of other amps and woofers that offer better performance than Kenwood. I don't know about the ones he is always PLUGGING.

I have stuck with JL AUDIO when it came to amps and woofers. That is just my personal preference. Mid and highs? No way would I go with JL..LOL

Also I do 100% percent of all my shopping on ebay. Stick to high sellers and remember..sometimes the company WILL NOT honor their warranty if bought from a NON AUTHORIZED dealer. Just a risk you take. I did. I never buy used. Always buy new! You can even get a better deal on last years models still in box. I bought alot of SOUNDSTREAM products that way. Bought a HUMAN REIGN amp like that. If you aint never heard of it.....google it. Its bad ***!