Panel thickness affects what frequencies are absorbed. In many home theatres,

1 inch panels: best when space is tight, mainly helps with higher-frequency reflections.

2 inches panels: the most common choice for home theatres, great for first reflection points.

3 inches panels: more control when a room still feels too live or “ringy”.

4×2 feet panels: popular because they cover enough area and are easy to lay out neatly.

If the main problem is boomy bass, we usually add bass traps instead of relying on thicker wall panels alone.