im currently working on a 2009 avalanche, we are going with 2 15'' nightshade v2 1) saz3500d.. I am ready for the box. my dimensions i can use are 49.5''x 20''x 30''. im looking for the most SPL i can get out of this thing. Ive been researching for days and have seen many, many different suggestions on how to set up the port/box. im currently confused as to what surface area i need for my port. im looking to tune AROUND 30HZ. any help/ suggestions i would appreciate it. the box i came up with was 49.5w x 20''tall x 25'' deep with a port of 18.5''x8.5''x 37.25''deep. will this work or should i go another route?

Not a box designer, but I would say you are fairly close. For "the most SPL i can get out of this thing" as you stated, wouldn't you want a little more port area and tune slightly higher?? Hopefully some other members will chime in and give their thoughts.

Not a box designer, but I would say you are fairly close. For "the most SPL i can get out of this thing" as you stated, wouldn't you want a little more port area and tune slightly higher?? Hopefully some other members will chime in and give their thoughts.

let me express how flexible that 30hz is, lets say the most spl i can get out of it keeping it in the more towards 30 than 40hz

I would go a little larger on the enclosure. Your running "low" wattage to a pair of NS's. The port area looks good and depending on what type of music you normally listen to i would shoot for that 30hz target for most rap and more towards 34hz or so with almost everything else IMO

Don't forget about cabin gain. Depending on what you listen to a bloated low end probably won't be desireable. Take Sefugi's advice if you're shooting for maximum SPL.

Making the box a little bigger willhave more gain and keeping the port the way it is will have more range musically. I would shoot for 5.5 cubes each sub after displacement

Making the box a little bigger willhave more gain and keeping the port the way it is will have more range musically. I would shoot for 5.5 cubes each sub after displacement

ok so my current air space is 7.88 after dp. now increasing my air space without altering my port would tune my frequency down, which i wouldnt mind because my current port is at around 33hz..now how much lower is the question? im really going for the hip hop style. ive built many enclosures so i would say im confident in my knowledge. ive just seen so many different applications for the NS and dont wanna have a hit or miss situation because im not tryin to hit 160 db. im trying to get as much as i can out of them the mechanically sound way. if that makes sense. i can get serious output of them but im not tryin to destroy the woofer in a couple months just for an extra .5 db.

7.8 cubes after all displacements is more than enough and I think that 33hz tuning would be great for daily listening and still do well on the meter.

Agreed, 33ish hertz is good for daily as well as being able to put numbers up if need be. Make sure you take pictures!!

Oh man, re-read the original post and realized he's working with 15's. I was thinking 18's. What a fail. Me<reading

Whats the best port placement? In the middle, or on the front standard L port.