difference is current 18" Fi subs?

[Karkov]

I have 4 - 15" in my Tahoe, behind C-pillar, at window line and they don't even have the air space that they should. Different model year though, I think mine has less room back there. Oh and mine has 6" of space outside the port. Box WAS designed for the subs and power BUT WITH the space available.

[Guest]

From what I've been learning that size port won't do anything, but I was wanting to know why it wouldn't, I'm more so trying to use the rough sketch I drew up in my head to get the information as to why certain things will and won't work so I can try to design the right box, know what I mean? Or should I say, "naaameen"?

barely any port area will just basically yield the equivalent of a sealed box that has air leaks.

if you cant pull off the general recommended 12 to 16 square inches per net cubic foot, then dont bother.

edit: x2 what cleansierra said in his last line.

I don't know where you heard that from, but that's not always true...hell ive ran 2 mayhem 15s with 70sq in of port and put up a 150 + did a box with 110sq in of port and didn't gain anything at my peak...did gain 1-2dbs in the high 20hz range though

i forget too honestly...lol. port area also sorta depends on how much the woofers are moving. more cone excursion = more air being moved.

[Jd1102]

I just posted how to find it there's a formula in the link

[Fuzzy336]

So if running minimum recommended airspace, should I use the minimum port size from those calculations or should I go bigger to make up for the lack of airspace?

[rockFord_Expedition]

I don't want to be one of those people, this is why I'm going question crazy, so I can try to build the system I would love to have but also make it sound great at the same time, I want to do it right. But I also want to be original, and I'm just trying to find that perfect balance

You don't want to be one of them, but you seem unwilling to compromise. I promise you none of these dudes will lose sleep if you mounted your sub in a funnel and stuck a flute on the end of it but if you don't build your box right, your 4 18's will be a joke. The box makes or breaks your install. Ask anyone that knows.

We aren't saying you will literally have 0 bass if you put 4 18's in 16 net cubes with 92" of port, because they will still move some air. It would be like owning a thoroughbred race horse but only letting it trot. What's the point? Might as well have saved some money and bought a donkey.

[Fuzzy336]

I'm at work so I don't have access to a calculator needed to do the equasions on the other thread, but does 47"x4" giving me 188 square inches of port and 10.44 sq inches per cubic foot at 18 net cubic ft and 4.5 cubic foot per sub seem a lot more practical?

Like I said I will do the equasion when I get home but that new port seems to be a lot closer to what everyone is telling me, and with th bl's calling for 5-8 would the half cubic foot of airspace short of 5 make a huge difference?

I just really want to run the 4 18's but I'm trying to factor in all of the advice I'm being given to make it as right as I possibbly can with the air space I'm working with.

[bassman619]

Honestly I would say go with two sundown zv4s and throw one amp on each..you make your life easier because ive heard their 18s only need about 6 cubes each..maybe 7..but I bet you could make a nice 12 or 14 ft^ box for those two plus ive seen ppl get a real impressive hair trick with only two zv4..

[Guest]

I'm at work so I don't have access to a calculator needed to do the equasions on the other thread, but does 47"x4" giving me 188 square inches of port and 10.44 sq inches per cubic foot at 18 net cubic ft and 4.5 cubic foot per sub seem a lot more practical?

Like I said I will do the equasion when I get home but that new port seems to be a lot closer to what everyone is telling me, and with th bl's calling for 5-8 would the half cubic foot of airspace short of 5 make a huge difference?

I just really want to run the 4 18's but I'm trying to factor in all of the advice I'm being given to make it as right as I possibbly can with the air space I'm working with.

not enough port area.

have you taken into account bracing displacement and sub displacement? the subs alone WILL take up 1.04 cubic feet. bracing, depending on what you use, WILL shrink your box space even further.

listen dude. either make your box height 4 or so inches taller, or downgrade to 15's. pick one.

we're trying to help make you louder. take the advice or end up with a sub-par performing substage.

edit: if you want 18's so bad, you have to make sacrifices. thats the name of the game

[Fuzzy336]

The gross air space before any displacement is like 21.59 so by saying like 18 cubic foot is considering some but not all displacement, and I'll raise the box height before I go down to 15's lol, I want to make this work real bad.

[Jd1102]

Honestly I would say go with two sundown zv4s and throw one amp on each..you make your life easier because ive heard their 18s only need about 6 cubes each..maybe 7..but I bet you could make a nice 12 or 14 ft^ box for those two plus ive seen ppl get a real impressive hair trick with only two zv4..

x2