What does Nominal Impedance mean?

What does Nominal Impedance mean?

I’m trying to decide on some new speakers (Clarisys Minute). They are rated at 86-88 sensitivity and a nominal impedance of 3.5 flat. Although graphs show it about 6 ohms from 20hz-500hz and at 2Khz and above about 3 ohms.

My present speakers, Focal Sopra 2 are rated as 91 sensitivity and 8-ohm nominal impedance, but minimum is 3 ohms.

So, I am presently using Bob Carver 350 amps (rated as 350 Amps/channel 8 ohm and 400 watts /channel 4 ohm) which are tube mono blocks. and I like to crank it up at times!

Can someone explain about Nominal Impedance and if my amp(s) will have a problem driving the Clarisys Minute speakers?



I vaguely remember that the speaker industry standard rating of impedance as what it is at 1000Hz.  Which is kind of silly because the impedance is usually all over the place unless the speakers use series crossovers.


Your explanation makes sense and seems to concur with what I read. (somewhere).


@clearthinker Wrote:

This poor manufacturer behaviour is mirrored by not quoting a dB range when specifying low frequency extension, and by over-stating sensitivity, which occurs very often.

(Proper) measurements matter.

I agree 110%! See the manual below of my speakers, it's the most comprehensive speaker manual of specifications I known of. They even explain how they arrive at their numbers. See last page specifications:



@fritzspeaks Wrote:

I vaguely remember that the speaker industry standard rating of impedance as what it is at 1000Hz.

JBL’s impedance graph is from 20Hz to 2KHz conforming to international standard IEC. International Electrotechnical Commission - Wikipedia


Let me ask another question:

So, does a 4-ohm speaker play louder than an 8-ohm speaker with the same amplifier and volume setting?