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?

ozzy

128x128ozzy

At Townshend Audio we match the average nominal speaker impedance (around 8oHms) with the impedance of the amplifier using Isolda 'impedance matched' Speaker Cable. Here we explore the reasoning behind our cable products: https://townshendcable.com/ 

Our Analysis uses a test set-up to prove how mismatched speaker cables will cause audible differences between a range of cables.

Thanks for your time.

Harriet Townshend

Yes Ozzy, this is the micro-site for the Townshend F1 and Isolda Speaker cables. Max tried to understand the clear differences he heard when hearing matched impedance cables Vs unmatched impedance cable.

Dedicated to understanding the phenomenon and spending a large chunk of his last years researching and testing.

His videos on You Tube called 'Geometry Matters' charts his reasoning.

Harriet

 

Harriet, thank you for that info.

I must say the Townshend F1 speaker cable is the best I have ever tried/owned, and I have tried alot, perhaps it is because of the impedance network built into the cable?

ozzy

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

It's entirely dependent on speaker's sensitivity and output level, which is usually measured at 1 m.

On the other hand, an amplifier will output more power with lower impedance.

Here's the output of Hypex NC400:
580 watts at 2 ohms
400 watts at 4 ohms

200 watts at 8 ohms

If you were to measure a speaker with DC you'd get a resistance. If you were to measure it with AC at various frequencies, you'd get impedance.