There are many stops along the spectrum of sound. To my ears, the Aurender A30 and A20 are very much linear and neutral sounding. The sound is clear, uncolored, and highly detailed. It's a pleasing, straightforward sound, neither warm nor bassy nor bright. I did my audio testing with the A30, but remember that the A20 has identical sound.
When I first started listening, I was waiting for that immediate "wow" factor. But this is a sound signature that isn't going to grab me immediately. That's a "me" thing, as I'm always going to be wooed by warmth. But while the "wow" didn't come right away, the appreciation built over time. After several hours of listening, I almost felt embarrassed by my initial underwhelm. I very much grew to appreciate the honest, unadulterated sound.
A real highlight for me was listening to Tracy Chapman's "Fast Car" on the Focal Stellia headphones with a Black Dragon Premium Cable. Everything about this song sounded just right. You know how sometimes you listen to a song you've known forever and suddenly you like it so much more than you ever remember liking it? That happened, and so I immediately put it on repeat and listened several more times. The music had so much depth to it; Chapman's voice had so much clarity. As amazing as the guitar strums sounded, it was as if the space between each strum had a character all its own, if that makes sense. This was a big part of my experience with these Aurenders - noticing these types of things. This is the difference between "critical listening" and "getting lost in the music" listening. A warmer, lusher sound might have me closing my eyes and daydreaming. The Aurender A30 and A20 have the sort of sound that makes you take notice of everything. If that's your style, the A30 and A20 will appeal to you.
I went back and listened to "Fast Car" with a different headphone – the Meze Empyrean paired with a Silver Dragon Premium Cable. The Empyrean has a warm and lush sound and a notoriously wide soundstage. The song sounded a little warmer, weightier, and "bigger." The Stellia's soundstage is taller than it is wide, whereas the Empyrean has more width. That being said, the Aurender's clean and detailed sound was very much discernible with both headphones.
Bass on the Aurender A30 and A20 is defined by, well, its definition. It's not overly assertive or rumbly, but it's textured and plenty satisfying. Mids are quite clear, with vocals always feeling front and center. Highs are peppy and detailed, but not shrill. A good test of "shrillness" is the alarm bell sequence at the beginning of Pink Floyd's "Time." If I wince, the sound is too bright. I did not wince here.
Sound summary: Linear, neutral, clean, detailed.
