Matching HK audio pro to amps

Discussion in 'Live Sound' started by ThomasM, Oct 9, 2009.

  1. ThomasM

    ThomasM Guest


    Being quite miserable at doing this sort of thing, I have a question:

    I have 2 amps delivering 2x1200 watts at 4 ohm

    Would it be possible to match those with:

    4 HK audio pro 18 sub 1000 watt program 500 watt RMS at 4 ohm
    4 HK audio pro 12 full range 800 watt program and 400 watt RMS at 8 ohm

    Is it possible without burning the hell out of my amps in a live mic'ed situation?
  2. moonbaby

    moonbaby Mmmmmm Moderator

    Feb 23, 2005
    You don't say what the amps are, and whether this is a passively- or actively-crossed-over system, and that can make a difference. That said, you need to do some quick math here. You have (4) 4-ohm subwoofers. Hooking each pair together in a "parrallel" arrangement (also called "daisy-chaining") will result in each pair being a 2-ohm load that each power amp channel will "see" (this is figured by dividing the rated impedance of 1 cabinet by the # of cabs- 4 divided by 2=2 ). Will each channel drive a 2-ohm load of low end subs? Maybe, but this is not recommended, you certainly CAN damage the power amps. At least overheat them and cause them to shut down. Not good on a live gig!

    You have 4 channels of power amp rated at 4 ohms, you have 4 subs rated at 4 ohms. You can connect each sub to a channel of power, that's OK. But now you won't have an amp for the top boxes, will you?

    Either acquire another amp for the top boxes, or designate 1 amp for the tops and 1 for the subs and only use 2 of the subs (1 per channel). The reason you can use the (4) top boxes on 1 2-channel amp is because those tops are 8 ohms each. A pair of them is a 4-ohm load on each of the 2 channels. Perfecto!

    As previously noted, there are questions regarding the crossing-over of the system that remain unanswered...Please provide more details...Thanks!

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