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SPL & SQ / Fabrication

Calculations, Concepts, Designs, Theories. All General SPL Or SQ Questions Can Be Discussed Here.

  1. Started by EPerez,

    I've always designed the box with the port on the side, but now I need it in the middle (using 2 subs). I do know that when the port splits off the port width gets halved, but is the whole length of the port mean that each side is the port length? Let's say I have a box that is 6" wide and 30" long. When it splits off each side will have a width of 3", but does each side equal 30" long? Someone also told me that you add half of the width of the port to each side of the port length. So each length would actually be 33" long. I don't know why that would work though. When I design boxes I use torres and there's a box that says "# of common port walls". I put 2 in there, …

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  2. Started by vice24,

    I found a formula that seems to work at http://www.caraudio911.com/ under designing a ported box. But I was wondering why on step four they say to subtract half the port width from the port lenght to get your physical port lenght? When I made my box I dont think that I did this so I may be building a new one if this is important. I was also wondering if this formula works or has been used by anyone here?

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    • 3 replies
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  3. Started by Bobby32,

    Alright so my box is 5.38 cubes internally after the displacements besides the port. Im using a tube port thats 8'' diameter and I want to tune to 32Hz. My box only has about 20 inches of height to work with inside, so some of the port will be sticking out the top. I want at least 4 inches between the port and the bottom of the box. If anyone can help me calculate it out that'd be appreciated.

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    • 5 replies
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  4. Started by swift,

    I have a question regarding port length and how to measure it in my application. I have decided on one 15in FI-Q in a downfiring ported console encloser for my truck. Question is: I have attached a photo of an example I did and I don't know how to figure the length. And also, how do I figure the port area and will this be enough for a 15in FI Q. A SA-1500v.2 will power the sub. The port will be 3.5in wide and 14.5 in tall (inside diameter) but how long will it be? Looking to tune at roughly 30hz and the box will have 3.65cu after displacement if this works. Is it A, B or C. Red would be airflow Thanks in advance

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    • 17 replies
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  5. Started by bigrank916,

    So Im designing a new enclosure and have come across a speed bump. Using the12volt slot port length calculator with these numbers: 24, 4, 6.13, 32= 33.13in Using carstereo.com port length calculator with the same numbers for a square slot port= 21.13in But when you change the option of slot port from yes to no, the new calculation is exactly 33.13in Why do they not match for the same thing? Shouldnt a square vent be shorter than a slot port? Did carstereo.com just flip flop them or something? Am I taking crazy pills or what?

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    • 13 replies
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  6. Started by Dexter Chaos,

    I have designed a box using Torres. Under port dimensions I have entered 33.5 as my length In the calculator it has a Physical Port length of 25. It also states that this will require me to make a bend but at 25 inches In my mind I was looking at it that I will make the two peices of wood a total of 33.5" long. 1. What is the difference? 2. Which should I use to make my cuts with? 3. Am I looking at that incorrectly? I am just confused now.

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    • 17 replies
    • 4.6k views
  7. Started by thebiggmann12,

    ok so i built a box for my new nightshade 18. it is just under 5 cubic feet before sub displacement but after port displacement. it is tuned to 31 hz b4 the sub. it sounds great. my question is if the port area is too small. the re calculator that i used said that the square port area was 55.5. idk if this means inches or what but im guessing inches. the sub performs great at higher frequencies but the lows are kinda lacking compared to the 18" fi q that i had before. any info would be great. also if somebody would be willing to design me an optimal box that would be great too. my dimensions are 36" wide 22" tall and 20" deep. sub and port would have to be facing up. i li…

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    • 5 replies
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  8. Started by edouble101,

    My next subwoofer enclosure setup in my Hyundai Elantra will be a subwoofer forward firing into the cabin sealed from the trunk. Would there be any disadvantages to having the subwoofer mounted behind the back seat and the port firing up through the rear deck (both sealed from the trunk)? I do not know if having the port and subwoofer that far apart and on different planes will cause any weird cancellation or any phase issues.

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    • 21 replies
    • 1.9k views
  9. Started by zyskatr,

    Hey everyone. I'm starting my first build today and the dimensions of my box are going to be around 34w x 18h x 16deep. I wanted to have subs up and port along the bottom of the box facing the trunk (its a hatchback) and doing that would tune it to high. Am I able to put the port in the middle of the bottom or does the port have to be along the whole edge it is on? If it has to be along the whole edge I will probly put in vertically on the back side on either the left or right edge. Please help, this is urgent. I'm going to be starting it in a couple hours. Thanks, Ted

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    • 1 reply
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  10. Started by EGAJohn,

    I have 1 PSI P1 15" sub in a 4.5 cubic foot ported enclosure. I have a 6" diameter aero port that is 10.5" long. My box is a 6 sided wedge design and we are trying to figure out where to place the port. I have a 2010 Hyundai Accent Hatchback and my box is in the very back. Here are my 2 options. Option 1: Port on top of box next to the sub. Option 2: Port in front of the box on the angle. If the port is placed in front it will be a few inches from the back of the seat with the seat up. If it's placed on top it will always be in open space. I would rather it in the front so i can blow more air towards the passengers but i dont want the seat to interfere with the sound qual…

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    • 2 replies
    • 925 views
  11. Started by garychurch84,

    My current box is 36"x16"x28" tuned @30 for 2 icon 12's.slot port.My question is would I benefit from building a new box with the port centered between the subs and fire the port thru the rear arm rest.Back seats don't don't drop down.98 pontiac gtp.

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    • 40 replies
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  12. Started by On3Hundr3dProof,

    I'm looking into building a new box and was wondering if there were any suggestions on the port's location. Its an extended cab truck and the subs and port will be upfiring with subs inverted. When competing it will most likely be USACI outlaw scoring with drivers door open. Would it be better to put the port on the passenger side, driver side, or center of the box?

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    • 1 reply
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  13. Started by jdawgg22,

    Okay, so...I am going to start my build for two 15" fi bl's in the trunk of my 97 chysler sebring, I can not quite remember what specifications, but it will be about 7 to 8 cubic feet. I am not sure whether it would sound better with the port facing in side the cab or toward the opening of the trunk, the subs will be facing up, and about 30-32 hz. Any input would be appreciated Thank,

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    • 4 replies
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  14. Started by zins184,

    Ok I have an 08 atima coupe and just redone my trunk floor for new box. Anyway I have 3.7-4.4cuft (internal box volume) to play with, I'm pretty sure a round port isn't going to work and not sure how to go about a slot or sqaure port. I know I need around 52in of port area for 32 to 33hz but I'm just stuck due to my box shape which I uploaded a picture of. any suggestions would be great.

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    • 13 replies
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  15. Started by SeductiveSounds,

    Ok, so I float around a few different forums and everyone has something different on the subject. Could someone please explain port loading? Why would you want have the sub in different locations in relation to the port? (close, far, centered on the face, etc) For example lets say for arguments sake; lets just have the port and sub on the same plain on the box for this discussion. I'm always trying to learn things to help me make louder, better boxes for my customers. I figure understanding this phenomena will help. Thanks in advance

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    • 0 replies
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  16. Started by fast85_gt,

    What is best used to paint the port latex? Or oil based mine is a wall with top port so it's the first thing you see just wanna make it pretty and any color sugestions?

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    • 5 replies
    • 905 views
    • 1 follower
  17. Started by frogcase2002,

    Is there anything I should look at when deciding where to put the port? Middle port, top port, driver side port or whatever. . . It is a b-pillar flat wall with 2 zcon 18s on 5k plus at first

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    • 4 replies
    • 1.6k views
  18. Started by mwerling1212,

    I have a 1990 lincoln towncar, and i need help deciding on where the sub and port should go. I had my ss rl-p18 in there, sub/port back, but i didnt like that. I cant put the sub forward because ltc trunks are like pits with no clear passage to the cab if you get what im saying. Thanks

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    • 6 replies
    • 867 views
  19. Started by TribeamConnek,

    I have a 1989 Dodge B250 Van. I removed the backseats and built a platform to hold a setup I am getting ready to build. I will not be building a wall. The subs were going to be facing the back of the van and my plan was to have the port on the back of the box. Do you think that would work properly or should I move it to the front. The speaker box will more than likely 21-24cubes and tuned around 32hz. It is supposed to be for 4 18's or 6 15's. I am leaning towards the 15's.

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    • 0 replies
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  20. Started by jdizzle,

    its going in my 92 civic 4 door in the rear seat area i was thinking sub up port up...but curious to see what sub up port forward would be. only reason to go in that area is because we could barely get a 5 cube box in the trunk without beating some stuff in box is gonna be 6 cubes at 36hz anyone have an experience in a setup like this one? im not sure if its exactly legal in most comps because the box itself is gonna be over the window line unless they would consider it a wall?

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    • 1 reply
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  21. Started by jdawgg22,

    okay, so I drive a 1995 honda prelude. I just got my nightshade 12 about two weeks ago =], I am running it with the saz 1500, I have also done my big three. I feel my nightshade isn't at the full potential but, it could just be my box. Off the top of my head I can not tell you my demension, all I can tell you is that its 2cuft at 33hz. I am planning on building another box very soon. I would like to know what input anyone has on they're 12" nightshade and there boxes and how they sound, also anyone with a prelude and where the have there sub mounted and the port faceing. Thanks, Jordan

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    • 8 replies
    • 979 views
  22. Started by cshaw,

    so, im currently redesigning yet another enclosure for my home theater mains. was wondering what the effects, pros, cons are on port placement. using a 3 inch round port. a 6.5 and a 1 inch tweeter. so top near tweeter or on bottom below mid or just rear firing? pros cons? im thinking port on bottom with about 2 inches of separation between port and mid.

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    • 4 replies
    • 692 views
  23. Started by fast85_gt,

    im doing a wall in my hatch back i will be doing bass race bass boxing and meca driveby but how will the best way to place the port drivers side? top?bottom? any help please oh and ill be using my 2 18"treo ssx subs

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    • 5 replies
    • 714 views
  24. Started by accordwithbass,

    Im using 4 4" aero ports. The box I will be mounting them to is 38"x20"x20" with an 18" sub on one side facing up. The 4 wont fit in a line since their flare is 7"+, so my question is, should I do sub in the middle with the ports on the side of the box facing back 4 in a row, or can I make a square with sub up port up, Will having 2 ports closer to the sub than the other affect anything? or will air movement be equal between the 4?

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    • 5 replies
    • 1k views
  25. Started by SaxMan,

    For a slot port is 2" for the width too small? Will there be port noise? Box Specs: width: 25 height: 13 depth: 13 wood thickness: 0.75 port height: 11.5 port width: 2 port length 1: 10.25 port length 2: 14 tuning Hz: 37

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    • 3 replies
    • 1.7k views

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