[garry742]

Okay So Im building a box for my two tc sounds epic 8 inch subs in the next week or so But I need to order aero ports and I would really like to know what size I should use? I was thinking one 4 inch tuned to 35 hertz but it might be hard to fit in my box, My box will take up one side and the middle hump and will be about 1.2 cubes Id like the aeros to be over the hump pointing out to the side not foward and if the 4 is to big which i think it will be should i do a 3 inch tuned to 35 hertz?
I was just wanting some suggestions and thoughts on this this will be my first time working with aeros and pretty much my first legit not hack job box this will be going in an 06 ext cab sierra and Ill be running the subs off of a audioque 1200d if that info is needed. Thanks Garett

 

[ibanender]

Are you talking about doing a single 3" or single 4" for a pair of subs?

 

[garry742]

Yeah I was thinkin a single 3 for 2 8s or maybe even two 2 inchers its going to be tuned pretty low to id like to be around 35 hertz if possible

 

[Twentyhurtz]

well since your limited on space.. i would try to fit a 4" port, even if you have to go with pvc and flare it yourself. Personally for a general box.. now this is by no means a general rule of thumb used by everyone, and by no means works in every application, or sub setup.. but i calculate my total cone area (not actual but based on subs outter diameter) and you have 2 8's so 100.48 sq inches.. personally if i was building the box, i would shoot for 1/3 of that in port area.. 33.4 sq inches of port area..
now a 3" I.D. port has 7 sq inches of port area, 4" has 12.56 sq inches, and a 5" has 19.62.. if i was trying to get close to 33 i would go with 2 4" ports.. but you do not necessarily need a lot of port volume because this is a daily setup, and tuned low.. you can get away with 1 4" port and i'm sure you will be happy, 4" aero's have about a 7" flange.. so maybe try 2 3" aeroports.. or just pvc and heat the ends and flange it yourself.

 

[garry742]

okay well the port I wanna get is 18 inchs long to I forgot to mention that and I can cut it down to the right size and thanks Ill end up going with one 4 inch aero

https://www.madisound.com/store/product_info.php?cPath=404_85&products_id=713

 

[ibanender]

Yeah I was thinkin a single 3 for 2 8s or maybe even two 2 inchers its going to be tuned pretty low to id like to be around 35 hertz if possible

That's not enough port area, not even close. I recommend a single 4" port for a SINGLE high throw 8". If you went with anything less than two 3" ports, it's gonna have a ton of port noise and may just act as a leaky sealed box.

but i calculate my total cone area (not actual but based on subs outter diameter) and you have 2 8's so 100.48 sq inches.. personally if i was building the box, i would shoot for 1/3 of that in port area.. 33.4 sq inches of port area..

That's still not accurate because the basket may be 8.5" mounting diameter, but it's not an actual 8" cone either. Even if you use the method of half the surround as part of the cone area, it's still gonna be 6.5". 1/3 of that is 11 sq in, which I know for a fact isn't enough port area. Cone area isn't a good way to determine port area because there is a displacement factor. An 8" that can move 1" has equal displacement to a 10" that moves 0.5". Then you have motor force factoring in beyond that....

but you do not necessarily need a lot of port volume because this is a daily setup, and tuned low..

That's like saying you don't need tread on your tires because it's just a work truck. If he's gonna listen to it every day, the box should be built CORRECTLY. Daily or musical doesn't mean the port doesn't matter.

 

[Twentyhurtz]

well my figures on the port calcs are just figurative, that is why i said by no means should it be taken at a generalized rule.. just something i use personally. As far as port volume yea true, a high output 8" sub will need more air flow.. but i'm assuming this is not a high output sub. I know assumptions are pointless but it's about the best you can do sometimes when you don't have a hand in the build.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=293-657
The sub looks beefy but looks can be deceiving.. take audiobahn for example..

OP, take the rubber boot off the magnet, will give you a little more box volume,and i know of people gaining from removing the rubber boot on the magnet, unless there is some severe turbulence caused by it.

 

[ibanender]

well my figures on the port calcs are just figurative, that is why i said by no means should it be taken at a generalized rule.. just something i use personally. As far as port volume yea true, a high output 8" sub will need more air flow.. but i'm assuming this is not a high output sub. I know assumptions are pointless but it's about the best you can do sometimes when you don't have a hand in the build.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=293-657
The sub looks beefy but looks can be deceiving.. take audiobahn for example..

OP, take the rubber boot off the magnet, will give you a little more box volume,and i know of people gaining from removing the rubber boot on the magnet, unless there is some severe turbulence caused by it.

The plastic boots are the deceiving ones, or like Audiobahn has with metal and mesh. The rubber boots aren't as deceiving. Big motor doesn't necessarily mean good, but that's a legit sized motor. Their xmax number isn't valid either. Xmax is SUPPOSED to be rated 1 way, and it won't move 22mm one way. 11mm yes, but 22mm is the limitation of the basket and the cone will hit the spider before that.

 

[garry742]

okay so am I going to want 2 three inch ports? what length am I going to want them? because Im not sure if im going to have enough room for 2 three inch aeros this box is going under my back seat

 

[Twentyhurtz]

Your max length will depend on your port style.. which may not matter, not sure what your allowed depth is.. PVC ports are straight obviously, but an aeroport has a flange on the end. I put 3 4" aero's in a box yesterday, and the flange on them is almost 7" O.D. so you need to see what you can have first. you can get the specs for aeroports on www.partsexpress.com. port length will depend on box sizing, air space, etc. Keep in mind the shorter the port, the higher freq the box will be tuned at. Also, a single port X amount of inches will be tuned lower than 2 ports the same length, just less air flow.

Can you post specs of your box, external dimensions, and are you using 3/4" mdf?

 

[ibanender]

okay so am I going to want 2 three inch ports? what length am I going to want them? because Im not sure if im going to have enough room for 2 three inch aeros this box is going under my back seat

Two 3" ports is still pushing it, I still think it's too small. The length depends on the volume and frequency.

 

[Twentyhurtz]

post measurements, maybe better to see if there is sufficient room for slot ports

 

[garry742]

If I had measurments yet I would I will post them as soon as I get them and Ill be using 5/8s seeing how there just 8s and I dont need the extra support of 3/4 and i can use the little extra air space

 

[ibanender]

If I had measurments yet I would I will post them as soon as I get them and Ill be using 5/8s seeing how there just 8s and I dont need the extra support of 3/4 and i can use the little extra air space

You're using big heavy subs, I see a need for 3/4". Especially with MDF, 5/8" may flex easily and maybe even strip out where the subs mount.

 

[garry742]

ohh yeah good point haha wasnt thinking about that haha these things weigh more then my old Fi ssd there supposed to be pretty much the same thing as RL-i 8s

 

[Twentyhurtz]

ha, just forget that 5/8 mdf exist.. all we can get here commercially is 3/4" mdf, we can get 1" but it has to be special ordered out of new orleans by the pallet.

 

[garry742]

Does anyone where I can get a bar sub grill like digital designs has on there pre fab boxs I emails DD asking about them but havent gotten a reply. its gotta be for an 8 ive found a ton for 10s and 12s but no 8s thanks

 

[ibanender]

Does anyone where I can get a bar sub grill like digital designs has on there pre fab boxs I emails DD asking about them but havent gotten a reply. its gotta be for an 8 ive found a ton for 10s and 12s but no 8s thanks

Parts Express used to have some, but now it appears they don't have any of the sizes on their website.

 

[garry742]

Parts Express used to have some, but now it appears they don't have any of the sizes on their website.

Do you have a part number for the grills you found? cause if there the right grill i might be able to call and have tell them what size I need id need the part number

 

[ibanender]

Do you have a part number for the grills you found? cause if there the right grill i might be able to call and have tell them what size I need id need the part number

I should have saved that, but no. I went to look on their website for them again but they don't have any sizes anymore.