amp and speaker cabinet matching?

Discussion in 'Amps and Cabs [BG]' started by moosapotamus, Aug 22, 2002.

  1. Can someone please explain the proper way to put a rig together? In other words, what are the basic rules of thumb for properly pairing up speaker cabinets with amps?

    For example, if I'm looking at a 2x12 cabinet that is rated 400W at 8ohms, what power amp should I use for best performance?

    Or (a different example), say I have a 1x12 combo rared 200W at 8ohms with outputs for an extension cabinet. What power/impedence ratings should the extension cabinet have?

    - Charlie
  2. Tsal


    Jan 28, 2000
    Finland, EU
    Amp that can handle 4ohm load(99% of amps can), can handle either one 4ohm cab, or two 8ohm cabs.

    These kind of amps sometimes have two plugs which say 8ohms on each plug(Hartke HA3500 for example), meaning that when you connect two cabs, they should be 8ohm cabs - you can connect it to single 4ohm cab too.

    And here's the power/ohm principle: 200w in 8ohm is as much as 400w in 4ohm. Two 8ohm cabs together make the amp think that there's only one 4ohm cab connected.

    So with that combo amp(it's inner speaker is 8ohm), you should connect one 8ohm cab to it. This makes amp give out power for 4ohm load, which it can handle. If you connect 4ohm cab to it, the amp gives out power at 2,6ohm load which most amps can't handle.