What does Nominal Impedance mean?

@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:

Mike

https://www.lansingheritage.org/html/jbl/specs/pro-speakers/1984-4430-35.htm

@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

Mike

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?

ozzy

What Mapman said. he nails it.  

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

no, depends on speaker sensitivity

and more broadly, i believe nominal impedance is basically a useless measure

speaker makers don't use the same standards and pretty much write anything into their marketing literature - always always looks at the whole impedance curve