Among an open-back collection that includes the Meze Empyrean, Audeze LCD-2, Abyss JOAL and HD 650, likes the 109 Pro's bass most and counts it among their two favourite open or semi-open headphones; it won't give closed-back slam.
“So: for open back headphones, these are top shelf in terms of bass (IMO). Of all my open back headphones, I like the bass on these the most - I'd give them an 8.”