question regarding Speaker Soffit design.

Hi, I'm sure this has been asked before but i cant seem to find a definite answer. On the top section of the soffit is the cavity lined with insulation or packed full of it (assuming measures are taken to account for any ventilation requirements). Most of what i have seen in the past have been lined, yet johns recording manual states that it is packed? also, whats the minimum density that would be required? if it was packed for example, would the loose type rockwool (rocksil in America i believe) be sufficient?

you fill the open space with light (15kg/m3) insulation batts with (as you noted) leaving space for air flow if you're venting. you can dampen the frame by lining the interior with rigid insulation (48kg/m3) and you should line the inside face of the soffit with it to fully dampen the face plate.

Thanks again Glenn