View Full Version : air leaks?
01-12-2003, 11:15 PM
actually i have a few questions maybe some one can answer for me. first do subwoofers really sound better after break in? 2nd how do i go about checking if my box leaks air? me and a buddy made this box so i am conserned that it might leak(althoe i did use alot of silicone).3rd i keep hearing about this polyfill! is this something i need in this box? and wouldn't it change my cu, space in the box. thanks
01-12-2003, 11:56 PM
1- polyfill -- if you have built the box to specifications, then you dont need it... if the sub calls for 0.75 cubic feet and you build the box to be 0.75 cubes, then you dont need polyfill.
but if you build the box to be 0.6 and the sub calls for 0.75, then 1/2 of a pound of polyfill will make the sub "think" the box is bigger and thus work as its supposed to.
2- leaks -- push GENTLY GENTLY GENTLY GENTLY on the center of the woofer cone EVENLY and STRAIGHT IN not at an angle. if the woofer cone goes in more than just a tiny bit, then you've got a leak.. also, if you hear ANY whistle, swoosh, or air-sounding sound. if there's a leak, the cone will push in very easily.. if there isn't... it'll be hard to push on.. also... if there is a leak, the cone will "return" to its normal position after your remove your hand very slowly, like its gotta suck air back in in order to ge tback to that position... if its not leaking, then it'll pop right back to where it was pretty quick.
just of note -- you should use a good solid bead of silicone caulk (100% silicone, not that acrylic crap) on EVERY internal joint of the box.... and if at all possible in the future when buidling boxes, use 1/8th inch thick "soft" foam weather stripping that is 3/4 inches wide... put it between every joint before you screw the joint together... then... silicone over that on the inside. that'll be "almost bulletproof"... so to speak.
03-21-2003, 01:34 AM
how small of a hole can create an air leak that will be noticeable (as in sound quality)? my box has silicone on all the internal joints, looks to be very sturdy (3/4" MDF), and i sealed the sub on with a foam gasket with caulk as well, i put caulk around the plastic of the speaker terminal to seal that as well.... when i press in lightly in the middle straight down, it doesn't pop straight out, it kinda takes a little bit. there aren't any sounds or anything either, just the delayed return to its orignal position..suggestions? thanks in advance
i could be wrong but doesn't Kim go against whats said about air leaks and how they react in this post? http://clubpolk.polkaudio.com/forum/showthread.php?s=&threadid=3449&
"It should give you some resistance and when you release it it should come up slowly. If it comes up as soon as you release it, then the enclosure has a air leak."
03-21-2003, 11:32 AM
i was speaking of small leaks, kim was speaking of large ones... out opinions agree with each other in that sense.
if you have a good solid subwoofer box with NO leaks, you will notice that as you push your sub in, as soon as u go a tiny tiny bit, resistance gets harder.... then harder... until you can't push on it anymore (unless u stood on the thing) and its only been pushed in a small bit.
if you can push your speaker in a little farther, and it makes any whistling noises (like air through a straw) going in either direction, u've got a leak... if it lags coming back up due to the fact that it has to suck more air through the leak and into the box in order to allow the cone tocome back up, then u've got a leak. usuallya "bad" leak can be as small as a screw hole. i recall i had something mounted to one of my sub boxes and later removed it -- plugging up all teh screw holes but one... caused lots of trouble until i plugged it.
if u have a leak you'll be able to push your sub really far back in its basket -- like all the way back till the surround looks flatted out. if you dont have a leak, u wont be able to do that.
if you have a LARGE leak (say 2 or 3 of those screw holes) then you'[ll push the sub in and it'll go all the way back in the basket just like with the small leak, but then it'll pop up really quick (as it sucks replacement air in more quickly through a larger hole than a smaller) -- this is what kim was referring to.
03-22-2003, 12:15 AM
i managed to seal it real well and the subs hardly move at all..
haha, i'd be lost without you guys, especially ya PpoweredByDodge. thanks for the info.
03-28-2003, 12:57 AM
what do u all think about using the carpet material that i covered the box with as a gasket ?i put alittle flower around the edge and i don't think it leaks but the carpet worries me
03-28-2003, 01:01 AM
i no this has nothing to do with woofers but what is spam? i see that in the commandments i always wondered what that is. spam?
03-29-2003, 03:16 AM
regarding carpet -- > if its really jammed in their tight, it should work as well as a foam gasket / rope caulk. if its loose, its gonna leak like a b#tch.
regarding spam -- > spam is like unsoliscitated email... ever get those random porno ad's or viagara or buy real estate in tahiti things in the email box? that's spam. no spamming in the boards :)
Powered by vBulletin® Version 4.1.6 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.