[joeybutts]

Hi guys. starting to think about getting back into working on my portable project. some changes have happened and i needed to change the sub stage. I was wondering if someone can tell me the volume and port dimensions i would need for two of these little guys. I have read anywhere between .25 and .8 PER woofer. I want them to get loud and low. I will be running them off of roughly 120 W total. They will be paired with a pair of HIVI B3S's. Thanks for any help!

Website-
http://www.partsexpress.com/pe/showd...746279#reviews

[joeybutts]

I'm trying to use this stupid WINISD and it is telling me they will only get to an SPL level of 86??

Or would i get more out of an Aurum Cantus 7"?

[aznboi3644]

Don't look at the SPL levels on WinISD...I never do. It isn't really that accurate.

[joeybutts]

oh alright. Well, i don't have a clue how big to make the enclosure for these things. I was thinking 1 cu ft for both, but don't know how big the port should be.

Any help?

[Gummie]

The SPL level on the initial graph is 1w/1m IIRC. It can plot output given a specific amount of power, but I have no idea how accurate it is.

Edit: port length is a function of port area (ie the smaller the port area the shorter it has to be). The more air you displace, the larger the amount of port area you need.

[joeybutts]

Oh, that makes sense. I can't believe i didn't notice that!

So lets say i'm shooting for an enclosure volume of .8, what would my port dimensions have to be tuned to 35Hz?

[Gummie]

Originally Posted by joeybutts

Oh, that makes sense. I can't believe i didn't notice that!

So lets say i'm shooting for an enclosure volume of .8, what would my port dimensions have to be tuned to 35Hz?

I'm assuming a round port.

one 1" port - 1.42" long (.785 sqin port area)
two 1" ports - 3.57" long (1.571 sqin port area)
one 2" port - 7.15" long (3.142 sqin port area)
two 2" ports - 15.76" long (6.28 sqin port area)
one 3" port - 17.16" long (7.069 sqin port area)
two 3" ports - 36.52" long (14.137 sqin port area)

The less port area you have the greater the chance for noise caused by turbulence. This can be reduced by flaring the ends of the port(s) or by increasing port area. I looked around online but I couldn't really find a good rule of thumb per say.

[joeybutts]

Ok. Now, last question hopefully.

I've figured out my enclosure volume is going to be right around 1.3 cu ft. It/they will be round port(s). If i go with (2) 2.5" round ports at 10" each, is that the right tuning for somewhere in between 30 and 35 Hz? Or do EACH of the 2.5" ports have to be 20"? I guess that is where i am confused.

[Gummie]

Originally Posted by joeybutts

Ok. Now, last question hopefully.

I've figured out my enclosure volume is going to be right around 1.3 cu ft. It/they will be round port(s). If i go with (2) 2.5" round ports at 10" each, is that the right tuning for somewhere in between 30 and 35 Hz? Or do EACH of the 2.5" ports have to be 20"? I guess that is where i am confused.

Each port will have to be 20" long

[mike93lx]

you won't need that much port area for those subs. I would do a single flared at around 2 to 2.5"

http://www.partsexpress.com/pe/showd...number=268-348

[joeybutts]

alright, I'll give that a shot! Thanks Mike!