It's good support for back. Lower back is firm, I use backfit at the most upright position, or sometimes slightly dialed back. It's hard to describe, i can feel it but its not unpleasant. When i tried aeron i didn't like that when i dialed posture fit to be most firm it touched my spine at the lowest point and i didn't like that. Embody is a little bit higher. And i didn't loke aeron when posturefit was on lose setting. I can understand that some people won't like that you can feel backfit, but i think without that there would not be enough support i actually didn't like aeron feel, but i guess that's really individual. It's really important to adjusr monitor height at eye level and chair height.

What have you asked about sound of the chair? I don't understand.