Everyone that's willing to spend more than $500 on a pair of speakers better consider all of the measurements that they might publish in Stereophile in a loudspeaker review. Stereophile reviews are a great balance between the subjective impressions of the main reviews and John Atkinson's measurement sidebar, where he comments, "I can see why the reviewer mentioned this coloration because of this peak or long decay or whatever…"
I never really understood measurements until I subscribed to the
Audio Perfectionist Journal by Richard Hardesty and Shane Buettner. Mr. Hardesty explains all the measurements and their varying importance but also how to listen critically and hear beyond the measurements for each component in your system.
Flat or on target measurements can tell you whether you are fooling yourself at a dealer by enjoying a short term coloration at a demo that may be fatiguing when you get the kit home.
Last month I attended a talk by Richard Vandersteen at a dealer and he explained his philosophy of a good speaker. Your loudspeaker needs to be time and phase correct in addition to a flat frequency response to pass an accurate waveform from your amp. A time/phase coherent speaker is defined by: acoustically centered drivers, one driver per frequency range and first order crossovers connected to the drivers in phase (meaning when the tweeter pushes the woofer pushes). Any deviation from these parameters and you have a lesser speaker. Get ready for colorations, smearing and tilted timbre that will not do justice to the original recording.
Only three current manufacturers produce time coherent loudspeakers: Vandersteen, Thiel and Quad ESLs. I have Vandersteen 1c's so I may be biased because I've spent money, but I think they're the best speaker for under $1000. I've never enjoyed my music more. The speakers' measurement make me feel secure and let me enjoy the music.
Mr. Vandersteen also taked about the disappearance of tone controls on our amplification systems and that loudspeakers and cabling have taken their place. Many speakers that can seduce a buyer at the dealer have a frequency response similar in shape to the inverted arc I set my boom box's 5 band equalizer to when I was twelve. The boost in the lows and highs would make badly recorded (too loud and midrange only) albums sound better.
It's hilarious that audiophiles will buy the most accurate and expensive sources and amplification only to have the signal mangled by a colored loudspeaker at the end. This is where your golden ear decides for you.
So yeah, flat frequency response is paramount along with spectral decays and step responses.
"Whatever sounds good to you" is a cop-out. Any experts on these forums should give their expert advice to raise our signal above the noise.