speaker impedance


New member
Aug 10, 2019
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Just had a look at my manual for my marantz pm5003, it's say's i should use speaker's with an impendace of at least 8ohms otherwise protection circuitry may be activated during play, my rx1's are rated at 6 ohms, what exactly does this mean? will it have an effect on the sound quality? is the amp suited to the speaker?


New member
Jun 10, 2011
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Impedance can be thougt of as the AC equivalent of "resistance". The lower the impedance and the more load is placed on the amplifier. That lower impedance draws more current.

The problem with speakers is that they are anything but a constant impedance. It varies depending on the frequency. As an example my B&W703's are "nominally" 8 ohms according to B&W but in fact dip as low as 3 ohms at a specific frequency.

To answer your question, the 6 ohms speakers should be just fine.

If you want to read up on it more look at these,


Good answer from Mooly.

Even so-called 8 ohm speakers will dip below that. The rated impedance, 6 ohms in your case, is a nominal figure. Magazines that show technical stuff that WHF avoid printing reveal as much. If you use a search engine to find 'speaker impedance curve' and look for images, you'll find graphs that look like big dippers. That helps show how nominal impedance ratings are.

Your Marantz will have a rated power output into 8 ohms and 4 ohms. The 4 ohms output should ideally be double, but in modest amps usually yield about 50% more. But your speakers will be no problem at all, and sound quality will be unaffected. If driven absolutely flat-out for a long time, the amp might trip out for safety, that's all.


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