ported clamshell help/build

[fritosaregood]

Explain.

if you have a 5 inch port it needs to stay a 5 inch width the whole way through.

Ill explain it backwards to make more sense..

if you have 2 2.5 inch ports L shaped ports on a box on a box that meet in the middle and join to make a T, Would you have 2 2.5 inch ports joining to make one 2.5 inch port? or 2 2.5 inch ports joining to make a single 5 inch port?

So if you have a 5 inch width at the beginning of the shell but you have ports one the top and bottom 6 inches from the wall they pretty much do nothing but act as a wall to stop air flow. if you were to bend it into a straight port it would look like a 5 inch port for a few inches then all of the sudden a 12 inch port. and that 12 inch port part would have no effect on the tuning.

[irpirate]

You could... I saw a write up once on someone who tested this with this type of "loaded" enclosure. They did it with nothing between, a small "v", and a larger "v" (presumably to help air flow). It was the loudest with nothing in there. Bigger the "v", the lower the SPL. I know that was his box and not yours- just saying. I would do it if it makes you happy- I intended to make one for mine and did not. I haven't noticed it as not being there.

ill probably just put nothing in there then. less work too

i bet you your wet finger knows more about this than me lol. ill just build it with 6" from the wall for both, then i can just add more if needed. i have to agree with you on the cant make the port too big thing, dont think the 12-16 sqin port per cube will apply. the reason i did the extensions of the port is because without those, the port is only 5 inches long. again this is based off torres for a ported box (only numbers i really have to go off of) iirc with 11 inches of port 36x6 port area itll tune around 35. but with what im doing the port will start larger than 36x6 then get smaller, which should raise the tuning of it. ill build it with the extensions on at first and see how it sounds. either way its gonna be a pain in the ass to add or remove port, and id rather tune too low than too high. basically impossible to know without building and testing is what im getting out of it lol.

build starts tomorrow!!!

subs arrive wednesday

[irpirate]

if you have a 5 inch port it needs to stay a 5 inch width the whole way through.

Ill explain it backwards to make more sense..

if you have 2 2.5 inch ports L shaped ports on a box on a box that meet in the middle and join to make a T, Would you have 2 2.5 inch ports joining to make one 2.5 inch port? or 2 2.5 inch ports joining to make a single 5 inch port?

So if you have a 5 inch width at the beginning of the shell but you have ports one the top and bottom 6 inches from the wall they pretty much do nothing but act as a wall to stop air flow. if you were to bend it into a straight port it would look like a 5 inch port for a few inches then all of the sudden a 12 inch port. and that 12 inch port part would have no effect on the tuning.

i dont think my box is gonna have many commonalities with ported ones. 11.5-12 cubes gross for 8 subs. after everything ill be getting a bit more than a cube per foot. i read somewhere that port area shouldnt only be based on box net volume, but xmax as well. 8 subs per chamber is gonna push alot of air. and as colin said, the clam will drop the tuning along with the subs interacting with each other. take a look at the angles and how the distance between the subs, should definitely act like an extension to the port. that being said i completely agree with your logic, it makes sense. but from what ive read on clams, all common sense, logic and knowledge on ported boxes kinda gets crapped all over. try to ballpark, build, pray for the best, and tweak if necessary. colins had experience with these things and has gone through the same stuff im going through figuring out tuning so im gonna trust him over common sense lol.

[AMI CUSTOMS]

But the thing you are forgetting is if you take the top section out, you would have a 2.5 inch port going to a 5 inch port. Not gonna work right, you have two cambers working against each other and the mouth of the clam back acts like a horn also adding to the port to some degree. I wouldn't make it 2.5 inches from the back wall with a 5 inch opening.

[fritosaregood]

But the thing you are forgetting is if you take the top section out, you would have a 2.5 inch port going to a 5 inch port. Not gonna work right, you have two cambers working against each other and the mouth of the clam back acts like a horn also adding to the port to some degree. I wouldn't make it 2.5 inches from the back wall with a 5 inch opening.

if its just the clamshell then yea, i would keep it 5"+ away from the back. but with the ported section added, you need to keep the area constant.

and youre not gonna take the top section out, so that shouldnt even be in the logic really.

[Colin - STAPUFT]

Nothing else to do but to build it at this point, really.

[irpirate]

starting today!!!!!! ill try n post updates

[irpirate]

so i got all the wood, 4 sheets of mdf cuz the birch at lowes was kinda shitty and really inconsistent. got part of the box put together but had to stop cuz i need the sub holes cut out on the face before i can put in bracing. i know the cutout diameter but id much rather just use the 16 cutout paper things that come with the subs. subs should be here wednesday. hopefully i can get all the holes cut then, get everything put together up and running by thursday before break starts.

[Sampsonite]

pics?

[irpirate]

mmm i dont feel like ive gotten enough done yet to merit any pics :/ only pic i have is 4 sheets of mdf on my 4runnner lol. subs come tomorrow though. pics will definitely get posted. ill try and remember to take tons.

exciting huh... -.-'"

i got all the wood precut at lowes so itd actually fit in my suv. that and i dont have any proper tools to do it myself lol. told the guy cutting i needed it exact. took over 1.5 hours :/