"DO NOT put fiberglass or polyfill in these boxes. The only time it might be ok is when someone desires to put a one inch layer of fiberglass along the walls to reduce midrange distortion if the woofer is to play high frequencies. Since this is car audio, land of active crossovers, this is not an issue. I repeat, do not put stuffing in a ported box."

"Ideally, a port should be on the same plane as the sub and as close as possible to the sub."

"the bigger the sub, the more moving mass. the more moving mass, the lower the fs. not to mention that because the length of the cone's widest point is greater it can play lower"

"In an SPL box, the air in the port will be too heavy to move until the tuning frequency is very close, then the momentum of the air will make it move alot, and make tons of SPL."

"In an SQ box, the port is small and the air in it isn't heavy, so it will move at frequencies farther away from the tuning, and you get better bandwidth. But at tuning, the weight is less, so there is less momentum to make it move more, so less SPL."

"The key is to choose materials and dimensions to achieve a musical set of panel resonances, and this is part of what characterises well regarded loudspeakers."

"A ported box will self destruct. The port is designed to resonate at a single frequency. At the tuning frequency, alot of the output comes from the port. The cone barely moves. This reduces some distortion around the tuning frequency and allows the ported box sub to have less X-max yet perform as well. But you'll never get infrasonic bass from a ported box."

"As for relying on spec sheets, keep in mind that the specs for whatever you are looking at , wasn't tested in your car, with music, or with speakers connected. so unless test tones is what you like, I suggest you trust your ears (did you know that it would take $20Million dollars to have scientific equipment that will equate what your ear can do? you got 2 of them, and in stereo!"

And people think the guy's on the high efficiency forum are nuts.... Until they take a look at stuff like termpro and sounddomain car audio forums!

I think I'll leave it at that - theres about 10 million more quotes I could do but I won't. One could die of shock from reading some of the things people post!

I remember Wayne said about 90% of stuff on the net about loudspeakers is wrong... probably true, sadly.

'my mate told me, that round ports dont chuff unlike square ones'

and a car audio man says=

''I tune all of my enclosures (no matter what size) to 40Hz. Only a pipe organ can play lower so 40Hz is suffecient in any system. The only time I tuna a box higher is when it's for SPL, then (and only then) I tune it to the RF of the vehicle. or unless I get a request for a specific frequency.''

very good a fixed tuning for all subs ,one size fits all!

its kinda annoying.

and then theres the 'sealed boxes dont resonate' brigade..

and the '4db peak in winisd sounds fine' people,seriously they cant know what theyre missing,a nice pi aligned box,flat response,or overdamped ported alignment...

no wonder so many people think ported boxes are boomy

also what i dont get,is how RESPL.com has the XXX woofers with high Q,and mid Fs, and people port them,and they peak heaps,compromising the XBL^2 effort into keeping the output clean!

it seems very strange

an 18" with 0.69 Qts ? crazy.

people treat xbl^2 like its magic over in car audio forums,if they had a woofer with actual useful specs for me,i would think about getting it and id want to get it measured for THD etc...
/end rant.
cheers!

I hope I wasn't out of line poking fun at those forums here. If I was then I am sorry for posting this, Wayne.