about a week ago i installed 2 15" 500watt rms subs in a sealed enclosure i built to manufacturer specifications along with a 4 channel Hifonics Zeus 1000watt rms amp where each bridged channel at 4ohms are used per sub (have to wait for my mono block in the mean time). Everything in the beginning sounded clean, smooth and loud with no distortion. Now recently im getting an extremely annoying plunk sound on bass hits and continuous clunky crrrrrrrrrr sounds on extended bass notes. Vibrate your tongue on the roof of your mouth and there you have the sound except with rubber and plastic. The shop said it was not blown as he free-aired it while examining the spider and coil. i put it in the box again and the same thing happens. There are no leaks in the box, there is nothing loose in the box and the amp is cool and green lit lol. No red protect warnings. Check this out, i push the sub in with my hand and there is no mechanical noise. What could it be?
seriously i'm starting to get pissed the f***in sh** off because whenever it comes to audio im never satisfied with my purchases or hard work installing. im seriously thinking of driving my car from CANADA (the land of BS goods and weak products) down to West Coast Customs in california, throw them my keys and say "when i come back, my car better sound clear and windows shaking"....flies back to canada.....
Ok after work today I isolated where it's coming from. I took the driver out of the box and examined it with a flashlight. The sub is no where near blown, the voice coil is perfect, the spider is perfect, magnet is perfect and a dustcap is not applicable on my model. After examining the driver i got it moving on some songs free-aired and i hear the plunky noise, therefore is not my box. Next I literally shoved my ear under the moving cone next to the voice coil and listened. Everywhere underneath the cone no such noise exists. The moment I have a close listen ontop of the cone, the annoying plunk exists around the center. What could it be?
take a rubber hose (1/2" diameter or bigger) about 12" long. stick it to your ear and point the other end at different parts of the sub. It will help pinpoint the area of cause. Also, have you checkd to make sure your surround is intact? Is it bottoming out? And what kind of sub is it?