Help with Wiring On a Sub

Discussion in 'OT Technology' started by Chi, Mar 5, 2007.

  1. Chi

    Chi OT Supporter

    Joined:
    Oct 20, 2003
    Messages:
    113
    Likes Received:
    0
    Hello, I have an Infinity Perfect 12.1 that recommends 350 Watts RMS Dual 4OHM VC

    I'm using an old Fosgate 750s which puts out

    187.5 Watts *2 Channels 4OHM
    375 Watts * 2 Channels 2OHM
    and 750 Watts * 1 Channel bridged 4OHM

    How should I wire the sub to the amp? The bridged 4OHM looks best of course but I don't want to blow my darn sub. Any recommendations?
     
  2. Zeromancer

    Zeromancer Pampita's Love Slave

    Joined:
    Jun 8, 2004
    Messages:
    26,887
    Likes Received:
    0
    Location:
    Simpsonville, SC
    1 DVC Driver
    Parallel When using a 4 Ohm Dual Voice Coil (DVC) subwoofer, the total impedance of this system is 2 Ohms.
    [​IMG]
     
  3. XR250rdr

    XR250rdr OT Supporter

    Joined:
    Mar 1, 2004
    Messages:
    24,475
    Likes Received:
    21
    Location:
    Ca
    Only problem is that amp isn't stable to 2 ohms mono.

    I would either buy another identical sub and run the coils in series and drivers in parallel or run that single driver in series. The amp should do roughly 375W @ 8 ohms mono.
     
  4. Chi

    Chi OT Supporter

    Joined:
    Oct 20, 2003
    Messages:
    113
    Likes Received:
    0
    Thanks, I don't really want to go with a two sub setup as I need my trunk space.

    I thought the amp could do a two ohm since the specs list 2Ohm as an option

    I was thinking maybe wire the sub in series for an 8OHM load?
    Since the amp puts out 750 x 1 into a 4OHM bridged wouldn't the 8OHM load knock it down to 375 RMS? Which should be about right for that sub?
     
    Last edited: Mar 5, 2007
  5. Zeromancer

    Zeromancer Pampita's Love Slave

    Joined:
    Jun 8, 2004
    Messages:
    26,887
    Likes Received:
    0
    Location:
    Simpsonville, SC
    Yeah that would work
    1 DVC Driver
    Series When using a 4 Ohm Dual Voice Coil (DVC) subwoofer, the total impedance of this system is 8 Ohms.
    [​IMG]
     
  6. Chi

    Chi OT Supporter

    Joined:
    Oct 20, 2003
    Messages:
    113
    Likes Received:
    0
    Thanks Zero

    Using one VC doesn't affect the longevity of the sub does it? Hard to find information on this topic, looks like a lot of conjecture
     
  7. XR250rdr

    XR250rdr OT Supporter

    Joined:
    Mar 1, 2004
    Messages:
    24,475
    Likes Received:
    21
    Location:
    Ca
    Using one VC is okay, but alters some parameters and halves the power handling. In your case your best bet is to run the sub with coils in series.

    When briding an amp you're effectively halving the impedence for each channel. So running 4 ohms bridged puts the same load on each channel as running a 2 ohm driver on each channel. So 2 ohms bridged would be 1 ohm stereo. There are few stereo amps these days that will run that kind of load. Before Class D amps were popular there were more of them, but they were pricey.

    Besides even if you could run the amp at 2 ohms bridged it would theoretically put out 1500W. That kind of power would toast that perfect in no time flat.
     
  8. Chi

    Chi OT Supporter

    Joined:
    Oct 20, 2003
    Messages:
    113
    Likes Received:
    0
    Thanks XR, looks like your advice is the one I'm going with
     
  9. XR250rdr

    XR250rdr OT Supporter

    Joined:
    Mar 1, 2004
    Messages:
    24,475
    Likes Received:
    21
    Location:
    Ca
    Have fun. I just metered my "new" Shiva last night. Now I have to decide what kind of box I want build.
     

Share This Page