These are a few designs I've been playing with. I'm putting these up here to get some feedback. I've searched and haven't been able to find any good threds on box designs. These boxes are all designed for 12" subs, but I'm sure they would work well with just about anything.
How would making the port longer by winding it like this affect port tuning and sound?
I've seen some boxes with deviders down the middle like thisone, and some without. I would think the devider would help. Any suggestions?
Alright ill take first crack at it, then as usual someone will come along and correct me and ill learn something too lol. Ok so starting with the winding ports. Thats done due to length of port for proper tuning. If you need a 25 inch port and your box aint that big you can double back. Poor example but still works lol. Ok now the Divider. The sub divier for one keeps the subs seperated to make your install a littler easier. The subs can cancle when in the same box if one gets a slight amount more power, or if the polarities are different. The divider where in the ports is the same as the box where the ports are on the other side of the box. Just a different design. And there are alot of forums with threads on box designs lol. Ok now like i said it will change the tuning by lenght of port. I suggest you go through and read all the facts on the forum it will help alot. Becuase alot of the answers you will get with this thread are repetitive of them.
all of those boxes will have pretty low tuning when you overlap port like that your lowering your tuning. the divider does help like subster said. i always put a divider in if im running more than one amp on my subs. also angling your port walls at the tips changes your tuning as well.
Is there a formula or anything to figure out how long to make a port to get the correct frequency out of it? Also when calculating box volume I suppose you don't include the port area correct?
The area for the port is not included in the total volume of the box. But proper volume for the port is crucial for tuning. You must figure out your maximum dimensions you can make the box including ports. Then subtract the amount of port room you will need. And there are lots of programs that do all the calculations for you on port size. Are you planing on using a slot port like your pictures or aero ports which i personally would rather use? Do you already ahve your subs or sub picked out? that would help? what kind of car are you working with. We can narrow down waht you need, and also help you figure out the general idea.
Winisd is the easiest program to use. http://www.linearteam.dk Download the beta version. You can input you're subs t/s parameters and can see how box size and tuning affect how it plays. But any subs parameters will work for calculation port length.
And you use the net volume of a box when calculating port length. Net volume is after driver and port displacement has been subtracted from the gross volume(total volume of box).
dividing the box simply protects the subs incase one fails during use, so as not to suddenly alter the box volume, makind the box suddenly appear twice as large to a single sub.