IMO: Anyone familiar with the previous relaxation of specs would likely conclude it was driven by manufacturers. I believe they (FTC) even say so. I am not sure how many folk knew about the last round of major changes. This time around, I think they got a lot more comments than they expected after notice for comments was placed here and on some other more technical audio sites.
but that in and of itself doesn't explain it. One would think that, then as now, the manufacturers would, by and large, prefer lenient (so to speak) requirements. One might further posit that they would've lobbied for same, as well! Back then, some good audio equipment manufacturers were still their own bosses, not owned by some big business conglomerates and also used high quality parts and labour force. They took pride in their work and about the image of the brand.
Before my time, maybe @Dennis Murphy has insight? Around that time (as I was working as a tech) I was told that several large and well-known "high-end" manufacturers actually pushed for it as they were fighting cheapo all-in-ones (and some others that should have known better) with absurd power claims. For example, I remember a Sound Design unit using 2N3904/2N3906 output transistors that claimed 100 W (or maybe higher) "peak instantaneous music power" or some such... Yeah, they might do it for an instant before they turned into slag.I wonder how the FTC "got away with" the rather extreme 1974 regulations? The claims for power amplifier output power in those days were certainly right up there in cryptocurrency territory
It could also be argued that the IHF standards already "in effect" in that same era represented a good-faith effort to provide meaningful numbers for power output related to real world requirements for playback of music.
1/8th power is the new normal, and even that is challenging to some amplifiers with high channel density.The original preconditioning requirement (of FTC '74) was pretty brutal, particularly in retrospect.
Well, maybe... IIRC it was the mid- to late-1970's when "high-powered" receivers started to appear, those having 100 W or more per channel. Before that, 10~20 W/ch models were common, so preconditioning at 1/3 power (admittedly designed to be worst-case for an AB amp) was at only a few watts vs. 10's to 100+ W for today's typical AVRs and amplifiers. And of course it is almost completely meaningless for class D. But IIRC, that spec was already relaxed to 1/8-power with the last major revision? Not something I follow closely.The original preconditioning requirement (of FTC '74) was pretty brutal, particularly in retrospect.
Yes, the 1/3 power requirement got diluted some years back -- I don't know when, though.
