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?



Jim Clark from Carver just replied to my email saying that the Carver amps would have no problem driving the speaker based on the specs in this posting. But I wish he had provided more detail.

Here is his reply,

"The nominal impedance is an average of the impedance curve. Many speakers vary between 2 and 20 ohms at various frequencies. Your 350's should have no problem driving them. Enjoy! Thanks, Jim"


+1 @milpai, To say he had a way with words is an understatement. Being a copyright lawyer (among other things) he was concise, succinct and a joy to read.

All the best,

+ another @milpai almarg is the one poster who could immediately answer any question! And I agree with @dweller nominal in this sense means average,