Anyone Wanna Give Me Some Insight.. Ported Box With Btl 18 Tuning

[preludesi]

think ive messed yet another one up lol, anyways i made the box for my btl. while trying to figure out port length it was getting late and i rushed. so the measurements ended up being 49 x 20 x 24 port opening 3.5... with a double top. i figured it to be around 10 cub feet inside.. i really thought for some reason that my resonant hz was about 35... i used one of those 30-130hz meters all number pointed to be around 40 to 50 hz.. while reading the other post about those hcca 12's vs the btl steve said as long as u dont go below the port hertz and give a clean signal there shouldn't be a problem.. playing music it sounds good to me but i really dont wanna blow it up etc... so my question is will this work or should i rip it apart and cut the port down and try the test again..

any help would be great..

Edited June 1, 2009 by preludesi

[bkolfo4]

so the measurements ended up being 49 x 20 x 24 port opening 3.5... with a double top.

Can you clarify? port opening 3.5? Is that 3.5 x 17.75? How long?

I do not see enough dimensions there to calculate what you have. . .If I missed something, let me know.

Brian

[preludesi]

the port measurement is 30" long by 13 high and 3.5 opening... from what i've been reading its like 22 hertz.. i made long at first to shorten once i get it measured to get the right feq, but when i checked it with the db meter it was the loudest between 40 and 50 hertz. i dont understand.. i thought it was gonna be loudest at mid 20's i cant see the port not being long enough.. its very long lol

thanks for the the reply by the way..

Edited June 11, 2009 by preludesi

[AI James]

not ebough port area

if you want for a small fee i can do it up for ya but you need more port area and dont need 10 cubes depending on power

[bkolfo4]

So your max dimensions are 49 wide x 20 high x 24 deep?

I assume you doubled the top so you have sub up, port rear?

I can put you a design together. . .confirm the dimensions.

Brian

[preludesi]

i have the room now so i made it big... no other reason it gets about 2500 watts.. sub up, port up, i really dont want to build another box.. this was a pain lol if so how can i make the port longer .. just add to it?

[Decaf]

so is the port 13*3.5 or 17.75*3.5?

if 17.75... holy chit.... i got:

9.82cuft

62sqin port

6.2sqin/cuft

21.32hz tuning

way to big

not enough port... you need twice as much

tuned way to low.... try 32hz

you need to rebuild... you wont hurt the sub likely with that power and tuning... but holy jebbus ask someone on here next time bro

if you lengthen the port ur tuning lower... which u dont want to do with a btl... ur in the home theatre tuning realm

Edited June 11, 2009 by Decaf

[bkolfo4]

Clarify the dimensions and then we can calculate adding another port. that would not be too hard and could fix the problem.

second port adds port area and raises the tuning. . .

[preludesi]

the dimensions of the length of the port is 30 the vertical length is 13 so total is 43 inches in total length.. its about 3.5 wide

hope this helps. but what is more confusing to me is why is it the loudest (db's) at like 45hz. not 20hz like the box is sorta tuned at..i thought what the box was tuned at is what it would be the loudest (db ) at.. just a thought couldn't i make some 45's in the box to take up some space mabey drop down the internal size...etc..

thanks again for the help..

Edited June 11, 2009 by preludesi

[preludesi]

ok finally figured it out... i went to the re calc page.. very helpful for ppl who thought they knew what they were doing lol.... so to make it 32hz the outside was 49*24*20 with a single 5 x 13.5 strait port... tested it.. sounds great... at least better then it was... thanks for the help guys.. u learn so much on here. hell i never even thought about port tuning years ago lol