I AM talking about nominal impedance rating, not dynamic.
If you have a cab with one 8 Ohm speaker that 8 Ohms IS the nominal impedance.
If you have two of those speakers in a cab the nominal will either be 4 or 16.
If you have three of them the nominal must be 24 or 2.67. (Assuming they are wired to all get the same amount of power.)
Double that to six speakers and you have more series parallel options but you never can get to 4 ohms nominal, not with speakers of standard nominal ratings.
You might come up with 3.2 nominal or 5.6 nominal as a couple of examples, but 4 Ohms nominal where all speakers are receiving equal amounts of power won't happen unless the speakers are all of a non-standard NOMINAL rating.
The nominal rating is what you should be using when deciding how to pair up cabs with amps.
Are the manufacturers just fudging this number to sound like something most folks understand?
Just like they round up power ratings? Who wants a cab rated for 392 watts when one "rated" for 400 will sell much better?
How many people who don't understand nominal vs dynamic impedance would shy away from a cab rated as 3.2 or 5.6?
How many more TB questions from noobs would there be when we deviate from the standard of 4 and 8 Ohms.
Given the number of people who don't understand impedance or power ratings, it's no wonder the cab manufacturers would rather just jiggle the numbers a bit rather than cause even more confusion than there already is. And if that's what's going on then that's all I need to know.
As an electronics tech, it is important for me to know as precisely as possible what is really happening with my gear.
Fudged numbers are the bane of our existence. If we know the numbers are a bit off, we can deal with that as long as we know how far off and in what direction. But a 4 Ohm cab with 6 speakers, and nothing else going on to explain it.