Are walls always louder?

[KilluminatiDre 10+ year member]

Well i guess i gotta crap ton of port area. Might as well see how it goes lmao. Once electrical is done ill have 4k to throw at them.

 

[kr15 5,000+ posts]

2 15s, sub up, port back in tahoe will do 150 on 4k

 

[Jeffdachef 5,000+ posts]

Well i guess i gotta crap ton of port area. Might as well see how it goes lmao. Once electrical is done ill have 4k to throw at them.

I'd honestly throw in some 2x4s and shrink that port. With that much airspace and port area and power your subs will unload really quick and honestly you might burn your subs up. When i had excess amounts of port area in my old setup with adjustable ports, the subs did not like it at all with more power put on them. They smelled extremely fast. Literally in Infinite baffle situations the subs handle a lot less power which is what you'll experience. Keep shrinking the port until desired output is reached.

 

[KilluminatiDre 10+ year member]

Ok, how would i position the 2x4s to shirnk the port?

So with a big port power handling decreases due to less internal resistance?

Im getting the 4k now incase i upgrade later but plan on lowering the gain initially so that im not overpowering.

 

[Jeffdachef 5,000+ posts]

Ok, how would i position the 2x4s to shirnk the port?
So with a big port power handling decreases due to less internal resistance?

Im getting the 4k now incase i upgrade later but plan on lowering the gain initially so that im not overpowering.

yeah basically. Just you'll find that in order to get anywhere near acceptable modest volume levels, the sub might already stink.

Just pile it on and decrease overall port area thats all.

 

[KilluminatiDre 10+ year member]

Ok thanks. Ill see how it initially sounds and start decreasing port from there. Maybe ill get away with it due to the pretty high xmax

 

[KilluminatiDre 10+ year member]

Car Audio - PORT Size Calculations and Formulas for WOOFER and Subwoofer BOXES

How accurate is this?

 

[shredder2]

180 in2 of port area with 2 IDMAX 15's in a 8ft3 net box... wow

14,000 watts of signal to get it to 27 m/s?... That's a much too large port...

And it looks like you'll need 17K to get there... 14K

 

[Jeffdachef 5,000+ posts]

Car Audio - PORT Size Calculations and Formulas for WOOFER and Subwoofer BOXES
How accurate is this?

Garbage. Better off using winisd. You wont get away no matter the Xmax, its excessively too much port. Only sub i know that actually requires anywhere close to as much port area is the DSS ethos but it also requires a smaller box as well and the IDmax is no where near that level.

See shredder's post.

 

[shredder2]

Looks like about 89in2 for a 4K amp in a 8ft3 net box with 2 Idmax 15's would work (that's tuned to around 35hz btw)...

You're gonna free air those subs with 180in2 of port and they'll most likely be bottoming out once you put the power on em'... I hope they got some KILLER suspension.

 

[Jeffdachef 5,000+ posts]

You're gonna free air those subs with 180in2 of port and they'll most likely be bottoming out once you put the power on em'... I hope they got some KILLER suspension.

they have very soft suspension hence the low FS. He'll rip em apart.

Only way 180 port area would work is if he shrank the box to 2 cubic feet and did a burp box tuned to 45hz and play one note only lmao. Easy 150s.

 

[shredder2]

Block off the slot port and use a 10" aero instead maybe... it'll be a 12ft3box... lotsa rise... IDK... might work?... tuned to 30hz it looks like it'll slam... for a 150 tho... no way

Might be rowdy tho... //content.invisioncic.com/y282845/emoticons/naughty.gif.94359f346c0f1259df8038d60b41863e.gif

Looks like a 5K to get the velocities where I like em tho... a 4K might be a little underpowered for that 10"... what a mess

 

[hispls 5,000+ posts]

With a port that large you may never get the subs to move enough to "use" the port

Way too much port area can cause the subs to act like they are in infinite baffle costing a fk ton of output.

It's like people don't even understand how a port works.

http://jahonen.kapsi.fi/Audio/Papers/AES_PortPaper.pdf

Try reading what actual engineers who know what they're talking about have to say on the subject if you want to understand ports.

180"^2 port is probably overkill but it's not going to do any of the things these people say unless something is wrong with how you laid it out. If a port needed to have a minimum airspeed velocity in it they wouldn't work at low power which is simply not true.

 

[tymoto21 10+ year member]

If any port is fine stick a single 8" with 180" of port...

It will act like a infinite baffle that hasn't been sealed off and it will not get loud

It will also reach mechanical limits much faster than building a proper sized box and port

there is such thing as too much port

 

[KilluminatiDre 10+ year member]

If it ends up being too much ill just cut 4 or 5 pieces of mdf the exact diemesions of the port wall and just add them one by one as needed. My internal volume is already what i want it to be.