designing a ported box...need help
01-11-2009, 12:47 AM
#1
designing a ported box...need help
ok so heres the deal, i'm planning on getting two new subs (just waiting on the money to show up in my bank magically), and i'm planning to build a box for each and then join them. i came up with an enclosure that gives me 2.13 ft^3 after driver displacement, but then i got to thinking about the port. it was going to be a slot port and need to be some 34 inches long so i figured i would make an s shape from inside to the outer wall, but then i got stuck.
if the port were 34'' long, 3'' in diameter and the box height was 18'' would i need to make the box 6'' longer plus 3/4'' for the middle sheet of wood to keep the same volume? the reason i ask is because i my head i'm thinking the end of the box is no longer the outer wall but the first panel inside the box that marks the beginning of the port, so my volume up to that point needs to be 2.13 ft^3 and the port would just be the port. i guess this is a little vague so maybe i'll try and upload a sketch to illustrate my point, but hopefully some of the seasoned vets can help me out.
i'm hoping i'm right because if my enclosure goes well then hopefully i'll build some more and then work on making my own speakers...big dreams indeed
if the port were 34'' long, 3'' in diameter and the box height was 18'' would i need to make the box 6'' longer plus 3/4'' for the middle sheet of wood to keep the same volume? the reason i ask is because i my head i'm thinking the end of the box is no longer the outer wall but the first panel inside the box that marks the beginning of the port, so my volume up to that point needs to be 2.13 ft^3 and the port would just be the port. i guess this is a little vague so maybe i'll try and upload a sketch to illustrate my point, but hopefully some of the seasoned vets can help me out.
i'm hoping i'm right because if my enclosure goes well then hopefully i'll build some more and then work on making my own speakers...big dreams indeed
01-12-2009, 12:08 AM
#5
ok so heres the deal, i'm planning on getting two new subs (just waiting on the money to show up in my bank magically), and i'm planning to build a box for each and then join them. i came up with an enclosure that gives me 2.13 ft^3 after driver displacement, but then i got to thinking about the port. it was going to be a slot port and need to be some 34 inches long so i figured i would make an s shape from inside to the outer wall, but then i got stuck.
if the port were 34'' long, 3'' in diameter and the box height was 18'' would i need to make the box 6'' longer plus 3/4'' for the middle sheet of wood to keep the same volume? the reason i ask is because i my head i'm thinking the end of the box is no longer the outer wall but the first panel inside the box that marks the beginning of the port, so my volume up to that point needs to be 2.13 ft^3 and the port would just be the port. i guess this is a little vague so maybe i'll try and upload a sketch to illustrate my point, but hopefully some of the seasoned vets can help me out.
i'm hoping i'm right because if my enclosure goes well then hopefully i'll build some more and then work on making my own speakers...big dreams indeed
if the port were 34'' long, 3'' in diameter and the box height was 18'' would i need to make the box 6'' longer plus 3/4'' for the middle sheet of wood to keep the same volume? the reason i ask is because i my head i'm thinking the end of the box is no longer the outer wall but the first panel inside the box that marks the beginning of the port, so my volume up to that point needs to be 2.13 ft^3 and the port would just be the port. i guess this is a little vague so maybe i'll try and upload a sketch to illustrate my point, but hopefully some of the seasoned vets can help me out.
i'm hoping i'm right because if my enclosure goes well then hopefully i'll build some more and then work on making my own speakers...big dreams indeed
01-12-2009, 02:24 PM
#7
yeah wide, my bad, i'm retarded, its 3'' wide, but i'm also wondering if i should make it a L shape or S shape inside the box
umm, the subs will hopefully be two 12'' Incriminator Audio Lethal Injection DVC 4ohm 600 rms/1200 peak and the amp will be a Crunch GP2500D doing 1250 rms at 1 ohm
umm, the subs will hopefully be two 12'' Incriminator Audio Lethal Injection DVC 4ohm 600 rms/1200 peak and the amp will be a Crunch GP2500D doing 1250 rms at 1 ohm
01-12-2009, 10:52 PM
#8
L shape port is the best way as I believe an S shape port would make it a T-line box, which is another animal altogether. What are the maximum outer dimensions you have to work with, don't forget it has to fit through the door. I am just learning Sketchup and Bass box so if Jalat has the dimensions he does some good box designs.
01-13-2009, 01:39 AM
#9
well the reason i was going with s shape was because i was building a separate box for each woofer and then joining them at the ports with a common divider. i figured that would be easier than a big box. i realize now the L port might be able to save me some space in terms of the length of the box, so thanks Nick. hmmm, maybe two small L ports instead of one big one... i think tomorrow if i can find some time i'll go take exact measurements of the space and sketch some diagrams and let you guys know what i come up with. all i know for sure is that i need between 2 and 2.5 cubes, but because money is slow i'm going off older model specs since i don't have the subs yet. i did decide to lower the tuning frequency so i need a longer port so i guess i have to change my specs again. man this is tough...
plus i think i might go with different subs. i have two old cerwin vega vmax and onlinecarstereo.com is selling the model up for 130 a shot, same power specs as the lethal injections, but still debating, doubt it but debating
plus i think i might go with different subs. i have two old cerwin vega vmax and onlinecarstereo.com is selling the model up for 130 a shot, same power specs as the lethal injections, but still debating, doubt it but debating
01-13-2009, 09:23 AM
#10
well the reason i was going with s shape was because i was building a separate box for each woofer and then joining them at the ports with a common divider. i figured that would be easier than a big box. i realize now the L port might be able to save me some space in terms of the length of the box, so thanks Nick. hmmm, maybe two small L ports instead of one big one... i think tomorrow if i can find some time i'll go take exact measurements of the space and sketch some diagrams and let you guys know what i come up with. all i know for sure is that i need between 2 and 2.5 cubes, but because money is slow i'm going off older model specs since i don't have the subs yet. i did decide to lower the tuning frequency so i need a longer port so i guess i have to change my specs again. man this is tough...
plus i think i might go with different subs. i have two old cerwin vega vmax and onlinecarstereo.com is selling the model up for 130 a shot, same power specs as the lethal injections, but still debating, doubt it but debating
plus i think i might go with different subs. i have two old cerwin vega vmax and onlinecarstereo.com is selling the model up for 130 a shot, same power specs as the lethal injections, but still debating, doubt it but debating
those lethal injections are an SQL woofer, you'll be very happy with them. PM me with your dimensions and stuff and i'll draw something up for you.
