sub blown, or dying?

ilikesound

I have an mm2084dvc sub, and i was tinkering with things in my trunk today with the music playing when i discovered that my sub sounds funny. it sounds like a cheaply made cardboard 6 incher from wallmart. there's this funny rattling sound eminating from what i think is the speaker...i know it's not over-driven, and it sounds fine for the most part inside the cab. what could it be? speaker wire hitting the cone? backwave? just blown sub? please help i have no idea what is wrong with it. it used to sound REAL clean and punchy, but now the clean sound has faded into something odd.

btw, it is in a sealed box to specs, with some polyfill inside the box.
also, what is a good crossover setting for the mmc6500 series tweets? they seem to be reproducing an aweful lot of frequencies that kind of cancel out my mids, since they are mounted up on the dash..

thanks for any input!

dohcmark8

Check that you do not have bass boost on the amp enabled. Check your gains.

zingo

I would pull it appart and double check everything. It could be any number of things, but you will never know until you get your hands dirty.

Installer4life

Sound like a voice coil rubbing. If it is not bottoming out then slowly push on the sub keeping it linear and listen. If the voice coil is rubbing you should be able to hear it and feel it.

ilikesound

looks like ill be investigating tomorrow. my gains are fine, never touched them after tuning most recently, perhaps 2 months ago...ill just take it apart and see i suppose..thanks guys

MacLeod

ilikesound wrote: »

I have an mm2084dvc sub, and i was tinkering with things in my trunk today with the music playing when i discovered that my sub sounds funny. it sounds like a cheaply made cardboard 6 incher from wallmart. there's this funny rattling sound eminating from what i think is the speaker...i know it's not over-driven, and it sounds fine for the most part inside the cab. what could it be? speaker wire hitting the cone? backwave? just blown sub? please help i have no idea what is wrong with it. it used to sound REAL clean and punchy, but now the clean sound has faded into something odd.

btw, it is in a sealed box to specs, with some polyfill inside the box.
also, what is a good crossover setting for the mmc6500 series tweets? they seem to be reproducing an aweful lot of frequencies that kind of cancel out my mids, since they are mounted up on the dash..

thanks for any input!

Take the sub out of the box and see if anything is loose, then play it a little out of the box and see if it still makes the noise.

For the MMC6500's, try turning the tweeters attenuator down to -6 db on the crossover.

1996blackmax

I assume that your mids are down low in the doors. Try reversing the phase on the tweeters, sometimes this helps blend them with the mids a little better.

MacLeod

Max has a good idea and another would be to leave everything in phase, then flop the polarity of just one mid. Tune to an AM talk radio station and take note of the announcers voice. Its a mono signal so it should be front and center and focused. If youre not using time alignment it will be over to the left a good bit but thats normal.

Now swap the phase of one of the mids and listen to the voice. Did the image focus up any? Did it increase in midbass response? If it did, leave the mid out of phase. If it skewed it all over the place and you cant physically point to where the voice is coming from, or the midbass response gets really thin, put it back in phase.