You may have noticed on the link I gave above that some speakers go lower than others. This does not necessarily make them better. You need to look at off axis response, distortion and impedance load in order to get an idea if a speaker will sound good.
Compare Dynaudio Focus 110. To the Dynaudio Confidence C4.
Obviously apples to oranges here as the C4 is TEN times the price of the Focus 110.
You will notice a similar frequency "range" (anechoic) but the similarity ends there.
Focus 110 is a small ported design and it shows up as oodles of distortion and a nasty sharp cliff drop in ultra LF (12 db/octave). Of course, for a small speaker, the Focus 110 has "astonishing" bass and would make a great near field mini-monitor for a small room even without a sub.
So it only when you look at the distortion figures that you realize that the C4 is a far better speaker (as it should be given its price). The C4 has distortion less than 1% for much of the useful audio range at decent 95 db SPL levels at 2 meters (live music levels).
Sadly, the Focus 110 has 1% distortion only between 1.5 Khz and 4 KHz (at the higher SPL test levels) with the rest far exceeding 1% and vastly exceeding even the cheapest electronic amplifiers distortion.
In the C4, only the tweeter looks slightly disappointing at high SPL - with the rest of the measurements looking stellar(it begs a question as to why did they skimp on the tweeter on such a stellar speaker?).
These basic measurements only help spot potential problems and it would be better to have more third party data, such as impulse or transient response measurements (waterfall plots). And, of course, good measurements performance just help to narrow down the speaker selection process because nothing can beat careful auditioning.