2 Polk Momo 12's blown

knite
knite Posts: 1
edited July 2006 in Car Audio & Electronics
I just got my subs replaced recently. a couple days later, one of them got blown again. i wasn't pushing them hard since i was breaking them in. is there something i'm doing wrong?

i have 2 MM2124's running on the C500.1
Post edited by knite on

Comments

  • MacLeod
    MacLeod Posts: 14,358
    edited July 2006
    I would say its something youre doing.

    First thought is youve got your gains set too high.

    If you do then its very likely youre pushing your amp into clipping which is sending out about 600 watts to each sub.
    polkaudio sound quality competitor since 2005
    MECA SQ Rookie of the Year 06 ~ MECA State Champ 06,07,08,11 ~ MECA World Finals 2nd place 06,07,08,09
    08 Car Audio Nationals 1st ~ 07 N Georgia Nationals 1st ~ 06 Carl Casper Nationals 1st ~ USACi 05 Southeast AutumnFest 1st

    polkaudio SR6500 --- polkaudio MM1040 x2 -- Pioneer P99 -- Rockford Fosgate P1000X5D
  • PoweredByDodge
    PoweredByDodge Posts: 4,185
    edited July 2006
    "clipping sends 600 w to each sub" ??

    um - no

    500 w rms --- i'll stipulate its underrated at 600w... 600w rms = 1200wpeak... rails at --whatever--... clip it out and you're not going to achieve anythign higher than the rms power output... you'll just get a nice ugly square wave into the thing. a 1200w peak square wave... yummy.
    The Artist formerly known as PoweredByDodge
  • MacLeod
    MacLeod Posts: 14,358
    edited July 2006
    When an amp clips, it generally sends out a signal that is limited only to its input voltage which is usually roughly double its usual output albeit at about 15% THD. Since this is a 600 watt amp running 2 subs, it sends out 300 to each sub, and if you doubled that, it would come up to about 600 per sub.
    polkaudio sound quality competitor since 2005
    MECA SQ Rookie of the Year 06 ~ MECA State Champ 06,07,08,11 ~ MECA World Finals 2nd place 06,07,08,09
    08 Car Audio Nationals 1st ~ 07 N Georgia Nationals 1st ~ 06 Carl Casper Nationals 1st ~ USACi 05 Southeast AutumnFest 1st

    polkaudio SR6500 --- polkaudio MM1040 x2 -- Pioneer P99 -- Rockford Fosgate P1000X5D
  • Greg Peters
    Greg Peters Posts: 605
    edited July 2006
    Just curious, what type and size box have you got the subs in?

    (I just bought a mm2124dvc for a friend's system and would like to know)
  • bknauss
    bknauss Posts: 1,441
    edited July 2006
    Uhhhhh, I don't know about some numbers that are being quoted, but if the signal is clipped, you can put out a LOT of power... a LOT more power than the subs can handle.
    Brian Knauss
    ex-Electrical Engineer for Polk
  • MacLeod
    MacLeod Posts: 14,358
    edited July 2006
    Ive always heard, read and been told that when an amp clips, its power output is limited only to its input voltage and it usually winds up cranking out power somewhere in the neighborhood of double its RMS rating. I know its not an exact number but ballpark thats about right....isnt it?
    polkaudio sound quality competitor since 2005
    MECA SQ Rookie of the Year 06 ~ MECA State Champ 06,07,08,11 ~ MECA World Finals 2nd place 06,07,08,09
    08 Car Audio Nationals 1st ~ 07 N Georgia Nationals 1st ~ 06 Carl Casper Nationals 1st ~ USACi 05 Southeast AutumnFest 1st

    polkaudio SR6500 --- polkaudio MM1040 x2 -- Pioneer P99 -- Rockford Fosgate P1000X5D
  • 1996blackmax
    1996blackmax Posts: 2,436
    edited July 2006
    Just don't make your amp clip........


    To the thread starter, there is something wrong and it is not with the subs. One sub going out... possible. Three subs going out, something is wrong with the setup.
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