I've met a lot of audio designers in my time, and all of the best = ones have=20 one thing in common, they have great "ears." They know what good sound = sounds=20 like. The opposite camp is populated with engineers that rely = exclusively on=20 measurements to "prove" their designs are better. To my way of thinking, = the=20 second group rarely makes great sounding products. Audio is too complex = to be=20 analyzed with just numbers alone.
Nowadays I'm meeting more digital audio engineers specializing in = designing=20 room and speaker correction software. They are usually very nice people, = and=20 their graphs and tests always look impressive on their laptops, but the presentations fall apart = when I=20 listen to their sound. Results vary from not bad to truly horrendous, = but great=20 sound is the least likely end product of their hard work.
Apparently, they were so focused on measuring sound they forgot to = listen, or=20 hire someone who actually knows what good sound sounds like. If the goal = was to=20 achieve better measurements I'd congratulate them for their = accomplishments. But=20 it's not, and discovering exactly what types of measurements indicate = improved=20 sound quality is an art. An art few of these engineers have = mastered.
There are a couple of reasons why measurements fail to correlate with = subjective sound quality assessments. First, electronics and speaker=20 measurements have little to do with the sound of music. Test tones are = too=20 simple and predictable; music is far more complex and random. = Reproducing the=20 sound of a violin or a drum kit are exceedingly difficult tasks, and = since the=20 real goal of any hi-fi is to play music and not test tones, the = designer's first=20 priority should be making products that sound "good" for the intended = market.=20 For example, if you're designing DJ headphones, you aren't trying to deliver = the most=20 accurate bass. Far from it, you want to pump up the bass. Amplifier = designers=20 shouldn't waste their time trying to create an amp to drive simple test = loads,=20 they need to make an amp that handles the complexities associated with = real=20 speakers playing music. And amplifier designers don't know which = speakers are=20 going to be used with their amps. Every speaker presents a different = type of=20 "load" to the amp.
In the 1970s there was a big push to lower the "total harmonic = distortion"=20 specifications of amplifiers to ever lower levels, based on the belief = that if=20 they measured better they would sound better. They were measuring the = wrong=20 things. The narrow focus of designing for measurements rarely produces = bona-fide=20 sonic improvements. That's not to say that in the hands of truly = talented=20 engineers measurements aren't useful, they absolutely are, but = measurements are=20 no substitute for listening.
I've heard all of the latest auto setup and calibration systems = featured in=20 Denon, Onkyo, Pioneer, Sony, and Yamaha receivers, and the results are = hit or=20 miss. Granted, these systems can improve the sound, but more often than = not, the=20 processing merely changes the sound. In those cases, I can = achieve better=20 results by listening and making adjustments with the manual speaker = setup. The=20 processed sound might measure better, but again, that doesn't = necessarily=20 correlate to sound quality enhancement.
I recently discussed the measurement quandary with my friend, writer = Brent Butterworth, = who=20 believes measurements are useful tools, but we never came to a meeting = of minds=20 on this matter. I'm paraphrasing here, but he said that measurements = that reveal=20 flaws in the sound of a speaker might go unnoticed by the ear, and that = some=20 speakers that don't measure well, can still sound subjectively good. So = there=20 you have it.
So if trained engineers struggle to derive useful information from=20 measurements, I can't imagine how consumers looking at a wiggly line on = a chart=20 helps them decide which amp or speaker to buy. I'm not referring to=20 specifications or numbers like watts per channel or driver sizes; I'm = talking=20 about charts and graphs that plot "spectrum of 1 kHz sinewave, D.C. to 1 = kHz,"=20 or "anechoic response of tweeter on axis." If you have ever picked up = useful=20 information from peering at charts in audio reviews, and you're not an = engineer,=20 please share your insights in the Comments section.