Broadband absorber thickness vs coverting area

The possition is front ,wall to ceiling joint. What would be more effective: 1.Two 120X60X10 cm panels. 2.One 120X60X15 cm panel. ?

The question is meaningless without knowing what you are trying to achieve. Andre

I agree with Andre, but generally covering more surface trumps more thickness. --Ethan

I'm treating my smallish room using broadband absorbers, I have determined the planning and placement for all parts of the room but this area where the front wall meet the ceiling. I'm not sure how to treat it - broader sized 4` (240X60cm) panels or narrower (120X60) 6` panels along the joint.

remember that the thicker the panel, the lower the frq it will absorp. Having a 30' wide panel, only 1" thick will absorp the hight frq in ye room. Leaving you with a very bass-sounding room. (the balance between low and high frequencies is disrupted) Making a 3'x3', 4" thick will be more broadband and there for result in a better frq-absorbing balance. As per Ethan: you can't have enough basstrapping. But be carefull not to absorp too much highs when adding "never enough" basstraps. Putting a screen in front (cloth/wood/plastic/whatever) could work to only trapp bass and leave highs in the room. It's really a matter of measuring your room at that point... (do I make sense?)