Getting 2 12 level 3 DC subs. Got a box designed out for them that fits the volume perfectly and has a smallish port.
The design I made has 2 layers on the top part (I don't know if that's necessarily but I heard it's best to reinforce the top plate since they take the most beating...but if not.. It'll take less work off my shoulder.)
Board being used is 3/4 MDF board. Port size 8x3x15 Box size 30x13x19
Suggested ported box for these subs are 1.5 cubic feet per sub, so the total volume is about 3.2 (the speaker displacement is .15)
Subs will be pointed up towards my glass and the port will be pointed toward my truck lock.
The box is tuned to 32 hz
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The design I made has 2 layers on the top part (I don't know if that's necessarily but I heard it's best to reinforce the top plate since they take the most beating...but if not.. It'll take less work off my shoulder.)
Board being used is 3/4 MDF board. Port size 8x3x15 Box size 30x13x19
Suggested ported box for these subs are 1.5 cubic feet per sub, so the total volume is about 3.2 (the speaker displacement is .15)
Subs will be pointed up towards my glass and the port will be pointed toward my truck lock.
The box is tuned to 32 hz
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Chunks of ABS sewer pipe are easier to adjust the length of. With a router circle guide and patience (make trial cuts on scrap MDF first to get the size right), you can cut the holes precisely enough for a friction fit. Optionally, cut the same diam hole through some scraps and glue those on the inside for more support. With a right-angle screwdriver you could put a screw or two through the inside of the port to lock it in place.
I guess the top piece of your duct could be just screwed in place, so you could remove it to adjust the length of the port. Or just don't glue the bottom pieces to the floor, so you can remove the whole duct to trim the length.
I guess the top piece of your duct could be just screwed in place, so you could remove it to adjust the length of the port. Or just don't glue the bottom pieces to the floor, so you can remove the whole duct to trim the length.
This is exactly what I do and it works wonderfully, except I use a cheap hole saw bit for my cordless drill.
If it works easier. As far as I understand, the only thing that's important is the volume of the port, but I could be mistaken.
I don't know, I'm used to doing sealed boxes so this port stuff is new to me...I may just add 2 slot ports about 2 " in width and 8.5" high and 16" in length...leaving a 2 " gap for the port end to wall. Slot ports to me, seem easier. I would either put the ports on the side of the box (facing the trunk) or the bottom part
This guy is recommending triangular ports. Slot ports and triangular and corner ports tune lower than equivalent area circular ports.
Large ports are needed for high excursion, a small port "blows".
Large ports reduce cabinet volume, catch 22.
Triangular front ports optimize the port area available.
Best to make the ports too long and reduce them to the optimum tuning.
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Ah thank you for the picture, I didn't know what he was talking about...now I gotta go look for a triangular port calculator.
Only problem with that is that I'm sure the triangle ports have to be on the faceplate where the subs are right? If that is so..it isn't going to work. I need to have my ports pointed to my trunk. and my subs are too big to fit on the side.
Only problem with that is that I'm sure the triangle ports have to be on the faceplate where the subs are right? If that is so..it isn't going to work. I need to have my ports pointed to my trunk. and my subs are too big to fit on the side.
Why do you "need" the ports pointed to your trunk?
Is that where you like to listen to your sub?
Port calculators only get you so far, if you want to "get it right", you will need to measure excursion (it will be at minimum at the Fb) and adjust port length.
I see, you want to port the cabinet for the added low end, then throw the added low end away by having it get lost in the trunk.
Makes perfect sense to me
Well I came up with a new design, since you are arguing about low ends..blah blah. lol.
New specs:
Box: 32"w x 13"h x 20"d.
Port: 3" w x 11.5"h x 21.5"d
..although it will one tight fit...I will be trying to put the subs on like most subs are...towards the trunk opening, and putting the Slot port in the center with a short divider going about 6" from the wall in the center of the port. Will have a sketch done when I get out of work..
Question can I have a 3" gap between cut around.
Ex. my depth is 20 inch...cut off 1.5in for the walls, gives you 18.5in to play with...so use 15.5in and stop, go over 3 inches from that wall and then 6 in from there.
New specs:
Box: 32"w x 13"h x 20"d.
Port: 3" w x 11.5"h x 21.5"d
..although it will one tight fit...I will be trying to put the subs on like most subs are...towards the trunk opening, and putting the Slot port in the center with a short divider going about 6" from the wall in the center of the port. Will have a sketch done when I get out of work..
Question can I have a 3" gap between cut around.
Ex. my depth is 20 inch...cut off 1.5in for the walls, gives you 18.5in to play with...so use 15.5in and stop, go over 3 inches from that wall and then 6 in from there.
An "L" shaped port will work OK, round the corner. Good idea to round the outside corners too, to avoid chuffing noise.
The extra resistance of the "L" bend will probably tune a little lower than a straight port.
Alright I got the pictures now.. I want to know your opinion on this one...it was one of my a design for my audiobahn subs...and I'm using L bend as you recommended.
The lines in the center represent the sub and how far it will go in. Now I have already calculated everything carefully...after subtracting the port volume from the box volume and subtracting the sub displacement, I got a box with 3.01 Cu ft volume, which is perfect. The volume recommended for these subs is 1.5. I don't know about the center piece b/w the port...but a guy name barron on here recommended it a while ago. I used it on my audiobahn box, and it works great.
The extra face plate is just insurance that my box won't blow apart...and I don't know think I'll be able to screw the sub in the first layer with out splitting the upper wood. So thus the face plate will be used.
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The lines in the center represent the sub and how far it will go in. Now I have already calculated everything carefully...after subtracting the port volume from the box volume and subtracting the sub displacement, I got a box with 3.01 Cu ft volume, which is perfect. The volume recommended for these subs is 1.5. I don't know about the center piece b/w the port...but a guy name barron on here recommended it a while ago. I used it on my audiobahn box, and it works great.
The extra face plate is just insurance that my box won't blow apart...and I don't know think I'll be able to screw the sub in the first layer with out splitting the upper wood. So thus the face plate will be used.
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I also made another model with the subs upward...pretty much the same specs and such, I favor the first one I made though instead of this...but if it's better, I'd use this one.
Unlike the first one, the ports are 2" x 18.5" x 21" with a 4" bracket in the middle...thought I don't think that bracket is a smart idea for such a small width port.
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Unlike the first one, the ports are 2" x 18.5" x 21" with a 4" bracket in the middle...thought I don't think that bracket is a smart idea for such a small width port.
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Calculate the area of a rectangular port using the triangle port "leg" dimensions. Divide by 2. Divide the answer by "pi". Take the square root of the answer. That gives the equivalent round port radius. Multiply by 2 to give you the equivalent round port diameter. You can also calculate this backwards if needed.
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