New Box . Need help please...

[jmgb4 10+ year member]

Well I am looking for a little help here. I have designed a box for my DC lvl 5 15but I think its a little small (4 cuFt) so I am going to try and get it around 5. The maximum dimensions I can use for a L port with displacement is around 4.8-.9. With aero ports I can get the box to a little bigger than that. I am also using a 3500D to power the woofer.

Here is my basic questions before I try and start to design it. I know that aero ports require less of a ratio than L ports (L is like 12-16 square inches per cuFt) but heres the question - what is the aero ports?

I was running numbers using the psp calculator and to get the tuning I want (35 hz) for daily requires a single 6" port about 9 inches long (The max depth is about 16 inches for me). The next tuning I want for competitions is 50hz and I would then toss in a second 6" tube 9 inches long (its actually 8.95 inches but 9 is close enough and easier). I would use a cap to seal one hole and somehow modify the box so I can easily remove and add a port.

My question is is 254 cubic inches (a little more actually because of the flair) enough for 35hz and is 508 enough for 50hz?

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[813thumper 10+ year member]

im no expert on aero ports but i will tell you if you are running 3500 watts to that sub you will kill it in 5 cubes. i would say 3.5-4 cubes with that much power.

 

[Cruzer 10+ year member]

Slot port area range is based on 12-16 square inches of port per cubic foot, while aero ports are based on 9-13

square inches per cubic foot.

thats copy and pasted from a ported box calculator program. not sure if its accurate or not.

im with thumper, they recommend 3.75, unless ur under powering it considerably, u wont need a 5 cubic foot box. and if ur using 3500, which is 1500 over the rated watts, u probably shouldnt exceed the 3.75, and should probably aim a little under that to increase power handling

 

[jmgb4 10+ year member]

0.o wow alright. I could have sworn they had an SPL section on their specifications and they recommended a 4.5 to 5cuFt enclosure. I went from a 3.5 to a 4.25 and noticed a huge difference (and flex of my car).

Ill keep the 5cuFt design then for a rainy day, and Ill start to do a enclosure for 3.75 cuFt...

Are you guys saying I will like blow the sub to bits? Or just shorten the life of it a lot? I have seen people put more power to a BTL (I know totally different woofer) in a 5cuFt box and hit amazing numbers for bassraces... If I find the video I will be sure to post it here.

 

[Cruzer 10+ year member]

well i would call up DC then. for a daily setup i wouldnt think that would be ideal, over powering, and well over recommended box size.

now if its just for competition, then sure, ur only doing it for a few seconds, it should be fine.

maybe someone else can chime in, ive only used the lvl 3 15

 

[jmgb4 10+ year member]

well i would call up DC then. for a daily setup i wouldnt think that would be ideal, over powering, and well over recommended box size.
now if its just for competition, then sure, ur only doing it for a few seconds, it should be fine.

maybe someone else can chime in, ive only used the lvl 3 15

Dont take it as disrespect or anything =P. I respect all of you who have an opinion and care enough to warn me. I shot Rusty an email and I am in the process of trying to figure out the best way to reorganize my trunk so I can do the easiest wall-into-cabin for a 3.75 to 4cuFt box.

 

[elancohen92 10+ year member]

Heres my .2

I would only do a 5 cubic feet box for strictly SPL use only. If you call Rusty at DC he will tell you that their subs are under rated. I would estimate the rms on a level 5 to be at least 2500 watts. For a daily driver set up I would do 3.5-3.75 tuned to about 32 hertz, IMO. Just remember though, the bigger the box = less power //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[jmgb4 10+ year member]

Heres my .2
I would only do a 5 cubic feet box for strictly SPL use only. If you call Rusty at DC he will tell you that their subs are under rated. I would estimate the rms on a level 5 to be at least 2500 watts. For a daily driver set up I would do 3.5-3.75 tuned to about 32 hertz, IMO. Just remember though, the bigger the box = less power //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I kind of thought so about bigger box = less power. Right now I am aiming for about a 4.25 cuFu box with displacement. But I did notice a huge difference between 3.75 and 4.25. The speaker has been doing great with a 4.25. I think if I try to stick around there I should be decent (but I am not getting the huge windshield flex like I see others getting).
I will try to post my new design but for some reason this forum is denying me the ability to post links.

 

[elancohen92 10+ year member]

Well if you want alot of flex then you need to move alot of air, so i would tune low.

p.s. i ment 3.5 - 3.75 after displacement and port. On SMD there is a really good box calculator that will tell you everything you need

 

[jmgb4 10+ year member]

Scratch this post.. I just realized I made a huge mistake...

I shouldnt have converted it to inches, its 9-13 per FOOT... Makes more sense now

 

[Kangaroux 5,000+ posts]

If you want to clear up things then PM someone like RAM or pro-rabbit

 

[jmgb4 10+ year member]

Well if you want alot of flex then you need to move alot of air, so i would tune low.
p.s. i ment 3.5 - 3.75 after displacement and port. On SMD there is a really good box calculator that will tell you everything you need

I have been looking for it but so far no luck.

 

[jmgb4 10+ year member]

Ok! here is what I have so far... I will do straight pvc tubes in a 4.25 cuFt box (will be about that after displacement and bracing).

Width:37.5

Height:17.5

Depth:15.5

CuFt before displacement:4.661

I will do 2 4" diameter pipes 5.5 inches long and have a cap (I hope I can get one that will be tight enough) to cap one off. For daily I will keep a cap on and it will keep my tune at 33hz. For comps I will uncap one and it will get me to 45-46hz. I will also sound deaden the trunk the best I can, wall off and foam what I can in the trunk.

What do you guys think? If you think its junk, let me know! I am just afraid that I have gone way over the rule of thumb for port area vs cubic feet rule.

 

[jmgb4 10+ year member]

Alright. I am going to have to foam my trunk instead of sound deaden because I am cutting it close here...

My new box is going to be 5.08 cubic feet BEFORE displacement.

Height:18

Width:38

Depth:16

I am going to toss the woofer on the far left side and then have 2 8" pvc ports stacked on top of each other. In order to get tuning low I need them to be LONG. So I will be placing the exit as close to the woofer as I can get (probably within a half inch) and then silicone that in place. They will stick out about two inches. They will go into the box 5 more inches (8.5 inches so far - remember double baffle) then turn away from the woofer and proceed towards the right side. They will go a total of 15 more inches towards the wall leaving about 5 inches to spare between the end of the tube and the right plate. With one tube open, I will get about 4.3 cubic feet of space left. With both tubes open I will have about 3.7cubic feet. That box is not ideal for SPL but thats the best I can do with the space I have.

One tube open = 33hz

Two tubes open = 46.5hz

Area for 1 = 50.2

The area is a little bit small but for what I am looking for its the best I can do. Suggestions? Comments? Anyway to save more space? Let me know.

I may just say forget tuning for SPL if I dont find a cleaner / better idea and tune for 33hz and see what I can do at comps with that.

I just realized.. How am I going to stop the tubes from clanking together?

 

[jmgb4 10+ year member]

bump / kick