Well i FINALLY ordered my Fi Audio 15" BTL about 2 and a half weeks ago and i decided to build a box myself.(not sure if this was a good or bad idea yet) and i've decided to go with the obvious choice of a ported box. My only problem is i cant seem to figure out the length,width, and depth that my port needs to be for the correct tuning. so heres the specs for my box and im shootin for a 35-37 hertz tune. Any help would be GREATLY appreciated!.
Box dimensions are as follows- these are INSIDE dimensions
H- 16.5"
W- 34.5"
D- 15.5"
assuming my calcs are right, I'm sitting at roughly 5.1 cubes right now not excluding the slot port. i like the slot port to be a full height port so the h on it will be 16.5" just not sure on the other two. and here is the link for the specs on the 15" BTL
https://ssl.perfora.net/www.ficaraudio.com/sess/utn;jsessionid=154a67e7a3af4fa/shopdata/0050_Speakers/0010_BTL/product_overview.shopscript
144db@38hz! It hurts so good !
if youre doing a slot port go to RE Audio and check out their slot port calc. I used it on my boxes and like it a lot.
All you have to really focus on is making sure you have between 14 and 16 square inches of port area for cubic foot of box.
And Anton, dont you dare tell him different!!!!!!!!!!!!!!!!!
Edited 1 time(s). Last edited Monday, November 16, 2009 9:34 PM
the re calculator is off a little. but it will get you there. it doesnt take every thing into effect. as in your sub displacement and support (you will need supports) and it doesnt take the double baffel into effect either (which oyu also need).
if your going to use that stupid rule of thumb use the full 16 inches per cubic foot.
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Anton Miller (PPC) wrote:the re calculator is off a little. but it will get you there. it doesnt take every thing into effect. as in your sub displacement and support (you will need supports) and it doesnt take the double baffel into effect either (which oyu also need).
Your supposed to factor that yourself. I wouldnt expect a calc to figure my sub displacement. Just figure the air you need including displacement.
And my last box was only 14.5 per cubic foot and I had NO port noise so stfu about the rule being wrong. I also have like 8.5 square inches of port per cube now though I am using aeros. I like my port velocity.
Also youre doing this for an SUV correct? Do sub up port back. Its a better option for that type of vehicle. Its also easier to keep your box below the window line that way which will allow you to stay out of the walled classes in dBDrag if you ever chose to do anything like that.
Edited 2 time(s). Last edited Tuesday, November 17, 2009 12:53 PM
TheSundownFire (JBO Chat) wrote:
Also youre doing this for an SUV correct? Do sub up port back. Its a better option for that type of vehicle..
im not convinced that the sub up port back is the best way for an SUV. But ive never done an install for an SUV so i dont know. and hatch back yes absolutly. but an suv i think it would benifit from firing backwards and bouncing the waves off of the back hatch compared to the roof. in a hatch it has an angled surface to bounce off of creating a natural horn design with will give you a natural boost.
but like i said ive never done an install for a SUV or a Hatchback. so im unsure.
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Anton Miller (PPC) wrote:TheSundownFire (JBO Chat) wrote:
Also youre doing this for an SUV correct? Do sub up port back. Its a better option for that type of vehicle..
im not convinced that the sub up port back is the best way for an SUV. But ive never done an install for an SUV so i dont know. and hatch back yes absolutly. but an suv i think it would benifit from firing backwards and bouncing the waves off of the back hatch compared to the roof. in a hatch it has an angled surface to bounce off of creating a natural horn design with will give you a natural boost.
but like i said ive never done an install for a SUV or a Hatchback. so im unsure.
Then don't give advice. Tell that to all the guys who run that, and they'll kick you in the nards. SUV and hatch work best sub up, port back.
Your car may do 13 sec @ 103 mph, but my car does 146db @ 35 hz.
Ive seen bajillions of SUV firing up. *Cough*Steve Meade*cough*
Lanman31337 - Cavfire wrote:Anton Miller (PPC) wrote:TheSundownFire (JBO Chat) wrote:
Also youre doing this for an SUV correct? Do sub up port back. Its a better option for that type of vehicle..
im not convinced that the sub up port back is the best way for an SUV. But ive never done an install for an SUV so i dont know. and hatch back yes absolutly. but an suv i think it would benifit from firing backwards and bouncing the waves off of the back hatch compared to the roof. in a hatch it has an angled surface to bounce off of creating a natural horn design with will give you a natural boost.
but like i said ive never done an install for a SUV or a Hatchback. so im unsure.
Then don't give advice. Tell that to all the guys who run that, and they'll kick you in the nards. SUV and hatch work best sub up, port back.
I just said im not convinced. not that it isnt right. i would like to try it both ways and see which way works best. i havent seen anyone do that. ive only seen people do it sub up port back and say its good. that wasnt advice it was an opinion and another option. id say try it every which way and see which one works best. If you have concrete proof that this way is better then please post a link. and dont post a link to steve meads vids please.....
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Im assume with the crapton of guys doing it, there has to be some basis.
TheSundownFire (JBO Chat) wrote:Im assume with the crapton of guys doing it, there has to be some basis.
The reason why i question ideas like this is because its my job to do that. im a design engineer and every time i design a tool or a product i have to ask my self why wont this work and do the research. when i ask my self why wont a rear firing subwoofer set up in a suv work better than an up firing i cant come up with why it isnt better. It is also part of my job to get into conflicts about pointless things like this, both ways will work obviously. but because a crapton of people use it does that mean its better? i mean more people use crappy sony subs compared to any other company. does that mean they are better or are the users just uninformed and following the crowd
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Anton Miller (PPC) wrote:TheSundownFire (JBO Chat) wrote:Im assume with the crapton of guys doing it, there has to be some basis.
The reason why i question ideas like this is because its my job to do that. im a design engineer and every time i design a tool or a product i have to ask my self why wont this work and do the research. when i ask my self why wont a rear firing subwoofer set up in a suv work better than an up firing i cant come up with why it isnt better. It is also part of my job to get into conflicts about pointless things like this, both ways will work obviously. but because a crapton of people use it does that mean its better? i mean more people use crappy sony subs compared to any other company. does that mean they are better or are the users just uninformed and following the crowd
Because it's the least destructive subs up and port back. the waves are almost in unison, instead of 1/4 wave or 1/2 wave out of sync. That's when you get cancellation.
Your car may do 13 sec @ 103 mph, but my car does 146db @ 35 hz.
I also figured it had something to do with the seat line also but that may not be correct.
TheSundownFire (JBO Chat) wrote:I also figured it had something to do with the seat line also but that may not be correct.
Only for competitions. There's plenty of clamshelled and walled SUVs.
Your car may do 13 sec @ 103 mph, but my car does 146db @ 35 hz.
Lanman31337 - Cavfire wrote:Anton Miller (PPC) wrote:TheSundownFire (JBO Chat) wrote:Im assume with the crapton of guys doing it, there has to be some basis.
The reason why i question ideas like this is because its my job to do that. im a design engineer and every time i design a tool or a product i have to ask my self why wont this work and do the research. when i ask my self why wont a rear firing subwoofer set up in a suv work better than an up firing i cant come up with why it isnt better. It is also part of my job to get into conflicts about pointless things like this, both ways will work obviously. but because a crapton of people use it does that mean its better? i mean more people use crappy sony subs compared to any other company. does that mean they are better or are the users just uninformed and following the crowd
Because it's the least destructive subs up and port back. the waves are almost in unison, instead of 1/4 wave or 1/2 wave out of sync. That's when you get cancellation.
then why do you get cancelation with a sub up port back in a trank car? you should be able to apply the same logic to that senario. if you have a seat that folds down and it is an open space, you should be able to do a sub up port back and not get cancelation. but you do.....
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I have a feeling it has to do with roof height vs trunk height and the refraction and reflection of the sound waves.
Anton Miller (PPC) wrote:Lanman31337 - Cavfire wrote:Anton Miller (PPC) wrote:TheSundownFire (JBO Chat) wrote:Im assume with the crapton of guys doing it, there has to be some basis.
The reason why i question ideas like this is because its my job to do that. im a design engineer and every time i design a tool or a product i have to ask my self why wont this work and do the research. when i ask my self why wont a rear firing subwoofer set up in a suv work better than an up firing i cant come up with why it isnt better. It is also part of my job to get into conflicts about pointless things like this, both ways will work obviously. but because a crapton of people use it does that mean its better? i mean more people use crappy sony subs compared to any other company. does that mean they are better or are the users just uninformed and following the crowd
Because it's the least destructive subs up and port back. the waves are almost in unison, instead of 1/4 wave or 1/2 wave out of sync. That's when you get cancellation.
then why do you get cancelation with a sub up port back in a trank car? you should be able to apply the same logic to that senario. if you have a seat that folds down and it is an open space, you should be able to do a sub up port back and not get cancelation. but you do.....
The reason I got it in the trunk car is because I had maybe an inch from the back deck, and maybe 2 inches from the trunk. If my trunk was full of baby seals, they would have all been clubbed by sound waves like baby jesus does.
Your car may do 13 sec @ 103 mph, but my car does 146db @ 35 hz.
My sub up port back got louder as we pushed the box back. But I have my amp mounted to the box and ran out of wire before we could slide it any farther. This seems kinda opposite of what youre suggesting Jeffrey considering that the trunk height gets shorter as it goes back.
Ok well I know you guys like arguin over utterly pointless stuff but only about 2 of these replies are actually helpful. Oh and as for an update, I ordered my kicker zx2500.1 yesterday so it shall be here in a week or so. Pics to follow
144db@38hz! It hurts so good !
Its not really arguing. Its constructive debate but Ill stop whoring your thread.
Whats the word on the box?
That is true sundown. But either way, iall I have left to do is decide if I want sub up port back or sub back port back and cut the last piece. Ill have pigs up in a day or so
144db@38hz! It hurts so good !
Pigs?!!!!!!!!!!!!!!!!!!!!!!
I still vote for sub up port back.
Yes pigs! So sub up port back it is! I'm so excited but its gonna suck cause my amp will be here in a week but my sub won't be here for another 3 weeks
144db@38hz! It hurts so good !
Soo I'm gettin sick of lookin at my 80% completed box just chillin in my living room si here it is.
Sub-up port back
5.1 cubes before
4.6 after disp. And double baffle port
15 sq. In of port per cube
4.7. X 15 = 70.5 sq. In. of port area needed!
Got some drinking to do tonight but it will be done tomorrow. Check for new thread and pics tomorrow
144db@38hz! It hurts so good !
Again, subs on the same plane for our cars, firing rear, will be the best. Brian - same box, sub and port rear, guarenteed it'll be louder.
Your car may do 13 sec @ 103 mph, but my car does 146db @ 35 hz.
I know but its just something I noticed while the judge was messing around with my setup. It was maybe a half dB gain sliding it back 6 inches.
