Differences in power output of different types of amps and speaker resistances...

[Nathan Raymond]

I happened across this video on YouTube:

I'm not familiar with John DeVore or his company, but it seems to me that he's implying there's some sort of conspiracy that started long ago between high-end audio magazines and equipment makers and how they list their specs so that people will spend more money on gear, but I think most of the reasons for the changes in design and specification in speakers and amps came about due to design tradeoffs and new directions that equipment makers went with their designs. Anyone have some insights?

 

[Blumlein 88]

A lot of smoke for not much of anything much less a reason to start his company.

I sort of agree with his rant. I don't know, but think the reason for the change, where it has changed, is no speaker (excepting Maggies) are 4 ohm, 8 ohm or whatever. They have a varying impedance and are not purely resistive. So I think testers just standardized on 2.83 volts as determining what voltage gave one watt and a given sound level was rather complicated with many speakers. So feed it 2.83 volts and measure SPL done.

Many likely missed the difference, but if you see it, and understand the spec you could translate it well enough. I don't think it had anything to do with amplifiers. And we are ignoring the uneven frequency response and the effect it has on measuring any of this.

Atkinson explains here the difference in a sensitivity rating and an efficiency rating which is what we really are looking at here.
https://www.stereophile.com/content/measuring-loudspeakers-part-one-page-3

In fact if you don't understand exactly what the video was about JA's explanation will make sense of it to you.