Im getting 2 edesign 12a's i modeled them in winisd pro and it says that 2 cubes each tunes to 25hz will give me the best curve im going for the best sq i can get here obviously i want to do a slot port, eh now how small can i go on the port area.... im probably only going to have a max port length of around 40" MAX i can do a 3x6x35..... but that seems kind of small most boxes i see have big ports, like 4x12 im not too familiar with port physics here thats why im stumped am i going to lose port volocity here if i go that small? would it be better if i went like 2x9x35? even tho tis the same port area? damn small box woofers! =) thanks for your help
18 square inches is plenty. It will keep the port noise to a minimum, and still provide output. My Brahma is temporarily resting in 1.9 feet tuned to 25Hz, with just a hair under 20 sq inches of port. The output is insane, and I'm quite impressed with its SQ too.
yea That is a common thing with people now days they want extreme port areas because they see them at the Local DB Drag well what goes for comps is not what you want for the street in all cases kinda like Real Drag Racing, things they use you probally dont want on your street rod.......
I too have a port question, is 10 square inches from one square port 2.5"x4.0" enough for no port noise for a 10"Jl 10W0 in a bandpass. Im making a bandpass that the port will be coming right up through the rear deck of a cavalier, so port noise is a major concern.
Should be ok. Be sure to round all edges going into and out of the port. Why into the cabin? Sounds to me like it would provide a peaky in cabin responce. Knowing your taste for SQ I might suggest you reconsider.
I'd be scared to port my B-15, it's pretty much insane in the sealed box as it is. I've found myself keeping my sub control pretty far down lately (4-5 out of 8), I've been getting more and more into SQ lately. As far as the original question goes... the original WinISD had a port mach calculator that would tell you if your port was large enough -- there is a formula for that but I don't know it off the top of my head.
I can't begin to tell you how sickening it is to sit it the car right now. My HOOD is rattleing. With it in the sealed enclosure, I had eliminated almost all outside noise. With my windows up you could hardley hear it outside. Now, all you hear outside is this obscene rattleing all the way to the front of the car. It's kind of cool to watch how it affects the smoke coming from the tip of a cigarette. It forces it toward the windshield in a pulsing zig-zag pattern. It is just sickening.
NAH, its not for me, its for my girlfriend. Shes happy with just her pioneer 6x9's, but she listens to alot of eminem and stuff and likes a little low end in the music. A single 10W0 wont do much from the trunk sealed off(I wanted to mount it sealed IN the rear deck, but shes got a third taillight in the way) so I decided the loudest I could do was a nice bandpass ported directly into the cabin. Ive wanted to play around and experiment with enclosure building some more anyways. AS far as SQ goes, forget it. She thinks the speakers in her TV sound as good as my home theater system I have with 2 audio concepts 12's a focal 7" polykevlar and a morel MDT33 tweeter per channel..... she just wants some more boom.
if you saw a 2 ft^3 box with a 4x12 port, it was most likely not tuned to 25 Hz......it would have to be waaaay too long.......just use the largest opening that will yield acceptable lengths..........also, port velocity is something you want to lose.......fast moving air causes turbulence, which robs you of SPL and shifts tuning frequencies............in other words, smaller ports give higher port velocities [bad], larger ports give lower velocities [good], but this is all relative to tuning frequency! WinISD is usually considered accurate enough for you to get a rough idea of port velocity on the graph that it provides.......ideally you want to keep it lower than 34.5 m/s, and round the edges of the ports as much as you can you can make the port larger and fold it inside the box, you just have to account for displacement, as the volume in the port is not considered box volume, and you have to adjust for correction factors if you use the walls of the box
