8 Ohm Speakers=4 Ohm ?

[Nelly]

hi guys a noob question. ive seen on richer sounds website when i look at speaker specs it says. Resistance. A standard figure is 8 ohm. Figure halves when doubling the number of speakers.Does this mean if a speaker is 8 ohm then a pair is 4 ohm ?

 

[tomlinscote]

Two 8 ohm speakers connected in parallel will have a combined resistance of 4 ohms if that is what you are asking but for a pair of speakers one to the left and one to the right channel they remain 8 ohms each. This is a nominal figure and will change with the sounds given out, some manufacturers quote a min figure too so you can see how low the figure goes in case your amp cannot cope with it. For example Quad quote a nominal figure of 6 ohms but say that this can drop to 3.5 ohms.............

Tommo

 

[Nelly]

thank you that has answered my question

 

[DocG]

Two 8 ohm speakers connected in parallel will have a combined resistance of 4 ohms if that is what you are asking but for a pair of speakers one to the left and one to the right channel they remain 8 ohms each. This is a nominal figure and will change with the sounds given out, some manufacturers quote a min figure too so you can see how low the figure goes in case your amp cannot cope with it. For example Quad quote a nominal figure of 6 ohms but say that this can drop to 3.5 ohms.............

Tommo

Hi Tommo,

what a coincidence you give the example of Quads. I'm looking into their ESLs, which seem to have a benign impedance curve (very benign for ESLs), with a nominal impedance of 8 Ohm, and variation of 4-20 Ohm, making them an easy load for an amp. In a Hifinews review however, the lab report measures (and I quote) "a minimum modulus of 2.7 Ohm at 20 Hz. Impedance phase angle at low frequencies is high enough to lower the EPDR (equivalent peak dissipation resistance) to a minimum of 1.4 Ohm at 69 Hz, but as the ESL-2912's impedance will be level-dependent at LF, the dip to 3 Ohm modulus at 7.5 kHz and to 1.6 Ohm EPDR at 1.1 kHz are more relevant and suggest a moderately difficult amplifier load." (End of quote). Any idea what this is all about? Do Quad give wrong specs? Or are these different things altogether?

BTW: just heard the ESL-2805s, and they were incredible! I was high for the rest of the day!

 

[tomlinscote]

err not that much of an idea really, sorry!

I was quoting the figures for their 25L speakers not the ESLs but I would have thought that if you were looking at these speakers you would have or are planning to get a pretty decent amp which would cope with them, Quad will obviously recommend their own valve amps so I would not have thought they were that hard to drive. If you are interested in the ESLs I would try phoning Quad and chatting to one of their engineers. I have done that in the past and the guy was most helpful and seemed genuinely happy to chat away!!

Tommo