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Why am I getting nothing out of my sub?

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    #1

    Why am I getting nothing out of my sub?

    I had a thin Rockford Fosgate sub, one of those little ones for boxes that go behind the seats in mini trucks, with some shitty amp in one of Luke's boxes. Shit sounded awesome, but I still wanted more. So I bought one of those DVC Obcon subs and a Planet Audio 1800.5 amp. Got everything installed and hooked up and I have to turn the volume up to about 80% just to get anything out of the sub, and even then it's barely anything.

    With my old setup, even just 50% volume was awesome bass.

    I tried a different set of RCA cables and it didn't help. I even thought maybe I mixed up the connections for the sub, so I switched the positive and negative terminals and it was exactly the same.

    I measured voltage at the input terminal and I only have about 6 volts. I thought that seemed low, so I ran a jumper wire straight from the positive side of the battery and somehow I still only had 6 volts.

    da fuq?

    :weak:
    Matt

    Originally posted by slammin.e28guy
    I pack my CD player with asbestos. Those mother fuckers pay dearly for stealing my shit.
    Originally posted by kronus
    try whacking parts of the motor with a wrench while yelling "YOU WANT SUMMA DIS? HUH?"
    Originally posted by chadthestampede
    This is like a reverse build thread; it starts out nice and gets shitty.
    Tags: None
    #2
    Check the wiring connections, gains/inout sensitivity and RCA cables. Make sure amp matches sub impedance.if there's a remote for the amp...install it.
    "I'd probably take the E30 M3 in this case just because I love that little car, and how tanky that inline 6 is." - thecj

    85 323i M TECH 1 S52 - ALPINEWEISS/SCHWARZE
    88 M3 - LACHSSILBER/SCHWARZE
    89 M3 - ALPINEWEISS II/M TECH CLOTH-ALCANTARA
    91 M TECHNIC CABRIO TURBO - MACAOBLAU/M TECH CLOTH-LEATHER

    Comment

      #3
      Oh yeah, I forgot to mention that. I wired the sub up as parallel and set the amp up for a 2 ohm load. Tried adjusting the input level, turned it up to about 25%, even turned the bass boost up to 25%. No change. Connected the remote input gain and maxed it out and still nothing.

      Seriously at a loss.
      Matt

      Originally posted by slammin.e28guy
      I pack my CD player with asbestos. Those mother fuckers pay dearly for stealing my shit.
      Originally posted by kronus
      try whacking parts of the motor with a wrench while yelling "YOU WANT SUMMA DIS? HUH?"
      Originally posted by chadthestampede
      This is like a reverse build thread; it starts out nice and gets shitty.

      Comment

        #4
        When in doubt, undo and start over. Something had to be missed, also make sure your wiring gauge is adequate for the power.
        @IRON-E30 aka Edwin:D

        Comment

          #5
          So you are getting 6 volts at the amplifiers power terminals? That's not good. Put you r meters negative probe on the ground terminal, and the positive probe on the power terminal from the battery, and note the voltage. Now move the positive probe to the remote turn on terminal. If they both read less than 12 volts, you probably have a bad ground. Check and make sure it's tight and to bare metal, or right to the battery terminal. If just one wire has low voltage, that wire is the problem.

          You said you wired the sub in parallel, when you talk about turning it up and it not getting louder sounds very much like the voice coils are wired out of polarity. Double check to make sure that the positive of each coil are connected to the amps positive speaker output and same with the negatives. DO NOT RELY ON THE MARKING ON THE SUB. Many times there is a production error and one coil will be marked wrong from the factory.

          Comment

            #6
            Hah, I never even thought to check the ground. Of course it was still good, though. -_-

            I guess I was just being lazy, though. I was putting the negative lead from the meter to the trunk instead of the ground terminal. When I put it on the terminal, I had 12 volts to both the input and remote turn on.

            So now I'm trying to take the sub out to check the wiring, but it's being a bitch. I had to hammer it in because it was such a tight fit and now I'm trying to get it back out without fucking up the box.

            But when I turn it up it does get louder, but I have to max out the volume just to get any decent bass out of it. And even then it's getting a lot of the highs, too.
            Matt

            Originally posted by slammin.e28guy
            I pack my CD player with asbestos. Those mother fuckers pay dearly for stealing my shit.
            Originally posted by kronus
            try whacking parts of the motor with a wrench while yelling "YOU WANT SUMMA DIS? HUH?"
            Originally posted by chadthestampede
            This is like a reverse build thread; it starts out nice and gets shitty.

            Comment

              #7
              Well, after a lot of finagling I finally got the sub out. Wiring was still correct.

              Tried hooking up my old sub and BAM, I have bass. Still doesn't really sound all that great, maybe because the amp is a piece of shit? I'm not even sure it can go down to 2 ohms, so I'm hoping that's why it doesn't sound very good.

              So I guess now I get to deal with getting a replacement amp from the seller. :drink:
              Matt

              Originally posted by slammin.e28guy
              I pack my CD player with asbestos. Those mother fuckers pay dearly for stealing my shit.
              Originally posted by kronus
              try whacking parts of the motor with a wrench while yelling "YOU WANT SUMMA DIS? HUH?"
              Originally posted by chadthestampede
              This is like a reverse build thread; it starts out nice and gets shitty.

              Comment

                #8
                How did you check that the wiring was correct? Pop the speakers using a 9 volt battery, and make sure they are both moving in the same direction. Also make sure both subs actually work. If one is blown it will move in when the other sub is moving out, and also cause what you are experiencing, as long as they share the same airspace. If they have a divider between them, that won't happen.

                Comment

                  #9
                  Is the low pass filter turned on on the amp?

                  Comment

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