Speaker Impedance

Discussion in 'Home Cinema Speakers' started by chuckalicious, Nov 1, 2005.

  1. chuckalicious

    chuckalicious
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    Hope someone can answer this.

    I have a set of JBL SCS 138 home cinema speakers, which, from what I can see on any website, say they have an impedence of 4 ohms. Now I don't really know what that means.

    However I am looking out for a new amp and liked the look of one of the newer Yamahas. This was quotes as 85W at 8 ohms.

    Will using this amp with these speakers damage either component?

    Thanks
     
  2. Reiner

    Reiner
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    4 Ohms for a speaker means it needs more power from the amp, i.e. it's harder to drive. However not only the impedance matters but also the sensitivity (measured in dB) - the higher the better; thus a combination of low impedance and low sensitivity could be a problem fo a low-powered budget AV amp, where all channels are shared by the same (typically weak) power supply unit.

    Most amps however have an impedance selector that will reduce the power in the 4 Ohm position to protect the amp, some manufacturers even go as far and don't allow 4 Ohm speakers to be connected (they state a requirement of 6 or 8 Ohm instead).
    In practical you can use 4 Ohm speakers as long as you keep volume levels within reasonable levels and as long as you lower the volume immediately once the sound starts to distort (clipping may damage your speakers).
     
  3. chuckalicious

    chuckalicious
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    Thanks for the info, I think that's cleared it up.

    I wish I'd known all this when I originally bought all my kit. That's what happens when BT hand around before enabling your exchange from ADSL!!
     

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