Tonal Preference
In my opinion, an earphone has to reproduce a sound as accurately as possible. Such accuracy is tested best on natural instruments such as piano, strings, and wind instruments. I therefore don’t like inflated bass and hence the frequency response should be leaning towards neutral with a bit of warmth added. My money is on the midrange.
I am of the strong belief that a good earphone should please the listener with all musical genres.
Testing Practice
I always test earphones/headphones over an ever growing cross section of music that provides a broad coverage of the frequency spectrum, including naturally generated sounds such as voices and classical instruments. Particularly orchestral instruments are important for assessing the timbre.
In my opinion, most earphone and headphone testers and tests largely ignore or underestimate the importance of “timbre” (= tone colour or tone quality) which is a key factor for musical enjoyment over a longer period of time. It is the timbre that makes us subconsciously enjoy our earphone/headphones most in daily use.
Most “spectacular” and spectacularly low-priced xx-driver earphones (balanced armature “BA” drivers only or hybrids) may have great technical capabilities such as detail resolution, soundstage, etc. but their sound is not as natural as that of a technically less competent single dynamic driver (DD) earphone. In most cases, I prefer the DD over a multi-driver that may turn a symphony into a painful experience. Reviewers who don’t pay enough attention to timbre are likely not listening to/testing with orchestral instruments. They are more interested in reporting the technical capabilities from their analytical listening as it also shows their own competence. But the technical capabilities of an earphone are not necessarily the most important criterium for the listener’s enjoyment.
I use the following sub-division of the audio spectrum in my descriptions:
