Listeners respond to how a song displays instruments and voice and while we can add descriptors such as warm, neutral, bright, resolution, detail, depth, separation, texture, etc., etc.,etc.,...one person's bright is another's just right.
Also depends on room, source and material, and how we trained our brain to listen. I have listened to amps that emphasize the upper mids and lower highs which was overbearingly unpleasant to listen to as well as sounding unatural to me.
Slightly accentuated highs seems to add to an airiness, sometimes. Depends on how much density/mass is in the notes being played. Some speakers sound weightier, some more light footed and I can find both pleasing but prefer one over the other depending on the material I am listening to.
Some speakers are deemed refined which I have found too refined and less transparent that I have hoped for even if they excel in other areas. Others prefer the refinement what they consider sound harsh to them.
Probably why we buy and sell gear looking for system synergy and the sound we want in the room we have. Take what works in one room and place it in another and the familiar sound may or may not sound as expected.
The speakers I have kept are Focal, Dali and Triangle.
Speakers I have returned or sold are Focal, Dali and Triangle. Same brand doesn't guarantee success up/down the line. Also sent back Dynaudio, Wharfedale, Boston Acoustics, Ascend Acoustics, Jamo, Martin Logan, Quad, etc.
Recently sold the little ML 15i which was alot of fun watching movies but never adjusted to it with music. Same with Quad S2. None of the speakers were absolute failures as many liked them. The only speaker that gave me listener fatigue was the Jamo. All my speakers can be considered low to midfi, same with equipment and as I listen at lower levels, it suffices.
Higher end equipment to me is for someone that wants to create a more lifelike concert like SPL experience, otherwise, the cost benefit of spending more decreases...as does our hearing as we age if we listen too loudly. That's also personal preference.
As to brightness, I think it's wonderful to have the overtones and textures of certain instruments exposed to hear and experience as long as there isn't glare, excessive sibilance, or other artifacts added from either the equipment used to record and process the sound. Then there's the recording itself to consider.
Strange but engaging hobby.
