It has been the "watts" war for the longest time. About time for them to start a high tech war, i.e. THD+N, XT.
Arguably that would make more sense anyway, not so much for audible improvements (but to give them a slight edge in competitiveness) because:
a) The older generation enthusiasts (try to be polite so I am okay to call them that
) had much fewer options to shape their favorite "sound", all they had were tone control, graphic EQ or roll their tubes etc.
b) Now we have all sorts of EQ tools, including auto room EQ and even harmonics generators (thanks Nelson Pass and others).
c) Many of those enthusiasts were blue collar workers who worked in noisy manufacturing environment for most of their career life, so their hearings probable were compromised even before age 40, and THD+N never really meant much to them. Instead, print magazine reviewers easily managed to prepare them to hear all kinds of sound signature often without understand where such "signature" came from and many excepted it as fact that Marantz, Luxman, tube gear = warm sound, Sony = bright sound, Bryston, Krell = neutral etc. etc... Smart marketing teams of Marantz (even Denon in the old days), Pass labs (in a different, perhaps more honest way..), NAD, Harman Kardon and some British makes had (still have, but may be to lesser extent) done an excellent job for them, successfully making it possible for them to hear the so called warm sound even though bench test results often showed they were actually very accurate/transparent in doing what they were desgined to do.
Now many of the older enthusiasts have waken up, and got educated, thanks to the internet in a way, and the more high tech oriented, science based electronic version of print magazines, such as Audioholics.com that have been providing numerous educational articles, reviews and measurements. Along with the younger enthusiasts, many of them have suffered less hearing loss, and are much better at EQ'ing their favorite sound and have no use for the manufactured "sound" that either are BS, or not cooked to their own liking.
So long story short, vanishing THD+N, i.e. SINAD for those who prefer that term, is probably the most important metric, not to say manufacturer should ignore other factors such as IMD, DF, FR, XT, FFT and a few others.
For those who want to argue that THD does not correlate to "sound quality", there could be a long story but the shorter version could be, imo, the following:
- It could be true that higher THD may even sound "better" to many people especially if the distortion is dominated by the lower order even harmonics, but even Nelson Pass had cited that a good proportion of people prefer 3rd harmonics to 2nd harmonics so it is not a given either. On the other hand, if THD is -90 dB, then who cares what the harmonic contents are, you can't hear any of it anyway even if you listen at reference level. So isn't it better to have it as low as possible regardless? That means manufacturers should set their goal on less than say, -80 dB at the minimum, but should be given in the format: 20 to 20,000 Hz, from below 1 W to rated output. Obviously, closer to -100 dB (100 dB SINAD) would be better as it would then guarantee any harmonic distortions will be masked by the noise in the quietest room that approach anechoic, may be not completely masked, to the super sensitive ears.
- As to "there are other things not measured, or can't be measured..." That's a silly point, because if there is something that is known to indicate the best sound quality, then we can be sure it would have been measured, audio electronics are not rocket science, not even closed., and if it can't be measured, then designers/engineers would have been shooting in the dark lol.. How many of such believers would jump in a huge passenger jet that has not been bench tested/measured/recorded, but rather just test flight to see if everything just worked to the liking of the pilots, since there are many things that can't be measured?
The thing about THD+N is that if it is low enough, one could reasonably assume IMD will also be low, linearity will likely be good, SNR, therefore DR will naturally be good too so THD+N is not just THD+N in a broader sense. XT is important obviously, but we know that all 7 to 13 channels popular brand AVRs measured could pass in terms of audibility, so along with DF and Slew rate, it would be nice to see those measured too but I guess that may be too much to expect mass produced AVRs/AVPs to include those in their specs. It may also be worth noting that with the advanced in electronics technology, we can expect more and more use of ICs such as volume control, DACs, OPAs; and PCBs are populated in highly automatic production lines. So we can expect consistent performance in terms of good DF, slew rate, much more so than in the old analog/discrete days, when those specs needed to be looked at under the microscope.
Sorry gents, I really hate long posts. Not going to proof read for typos/grammars for sure.
