The opposite effect, where high pitched sounds linger, can be very annoying. This is the situation in many indoor swimming pools. To provide even reverberation, the shape of the walls should be complex, but not very regular. A regular structure, such as a staircase, will often produce a series of echoes called flutter echo. Isolation Control of reflections and reverberation can satisfy the first three goals on our list.
Isolation is a matter of the materials and techniques used to build the room.
Attention must be paid to such details as air ducts and holes for electrical cables, for sound can leak through any opening. Once an adequately isolated structure is finished, noise generating devices must be kept out. Adequate isolation is almost impossible to achieve after construction if it was not built in in the first place, but since it is an issue that is very important to low budget recording and electronic music, here are a few things that can be tried. First, find the leaks that sound follows between the studio and the outside world. Edges of doors, vent ducts, electrical outlets are all suspect.