Does this look right?

CH46ECH46E Posts: 662
Im trying to wire up 3 single voice coil 4 ohm subs on one channel. If i can get 2.7 ohms like this pic shows ill be good to go.

This look accurate? And would all three subs receive the same amount of power? Ok to put them in one ported chamber?

dofrat9ur10c.png

Comments

  • FestYboyFestYboy Posts: 2,785
    Ok, so sub 1 and 2 make an 8 ohm load that is then paralleled to another 4 ohm load... To me that becomes something like a 5.x ohm load.

    I could be wrong though.
  • mhardy6647mhardy6647 Posts: 19,072
    It is as the Yboy says in principle, although I think he slipped a digit someplace doin' the arithmetic :(
    Ohm. He is the Law. B)

    dofrat9ur10c.png

    Resistances (or Impedances)* in series are additive.
    Rt = R1 + R2 + ...

    Resistances (or Impedances) in parallel follow a rule like this:
    1/Rt = 1/R1 + 1/R2 + ...

    In the illustrated case: R1 and R2 are in series, so Rt for those two is 8 ohms.

    R3 is then wired in parallel to (R1 +R2), so, in this case:

    1/Rt = (1/8 + 1/4)

    1/Rt = 3/8

    Rt = 8/3 = 2.67 Ohms

    _________________
    * Voice coils passing AC waveforms (music!) are reactive devices and as such the parameter of interest is impedance as opposed to resistance (which applies only to DC circuits or those without inductive or capacitive components). Technically, impedance is called Z and resistance is R, but both quantities obey Ohm's Law :)
  • FestYboyFestYboy Posts: 2,785
    When the doctor speaks, knowledge is bestowed. I neglected the least common denominator (derp).
  • mhardy6647mhardy6647 Posts: 19,072
    Well, you know what they say:
    Give a man a fish, and he is fed for a day.
    Teach a man to fish, and you won't see him for the rest of the weekend.
  • CH46ECH46E Posts: 662
    Well, after looking at all the specs for the class d amps i was looking at, i think i just need to source one more driver and make it 4 and just run two 2 ohm loads.

    Thanks for the ohms law lesson!
  • mlistens03mlistens03 Posts: 2,144
    CH46E wrote: »
    Thanks for the ohms law lesson!

    Ditto!
    Not Tom, or Trey, or Jim
    NAD C352
    Monitor Audio Radius R90’s/Mission Freedom 770 IV
    BJC speaker cables, generic RCA’s, one homemade power cable, because that’s going to do any good with the rest of the generic ones.
    Technics SL3200 turntable and a Shure M97xE phono cartridge
    Velodyne VA-907 subwoofer
    Lafayette LR-1100 acting as a tuner and phono.
    I've always thought the goal of high end audio was not to have your neighbors bang on the wall and say, 'Turn that darn music down' but to have your neighbors bang on the wall and say, 'Tell your friends to go home and you can practice later this week'.
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