The positioning of sound absorbing finishes has a great bearing on the effectiveness of the acoustic properties. Incorrect placement can reveal and accentuate unwanted sounds.
In lecture halls projections in the ceiling surface should not be used, as this can produce a delayed echo unless absorbent.
Mutually acute angled surfaces should both be fitted with sound absorbents.
In rooms with large ceiling height, both ceiling and wall surfaces located above normal storey height must be treated. To prevent flutter echo between parallel walls absorbers should be used on the whole wall surface of at least one wall in large rooms.
Adjoining rooms with shared opening may act as sound amplifiers in relation to each other. Sound absorbent treatment need to be fitted in both rooms.
Don’t position quiet rooms next to active spaces with long reverberation times. Use a transitional room to act as an acoustic buffer and treat it with absorbent finishes.
Conference rooms or auditoria must not only emphasize the speaker's sound but also attenuate unwanted reflections. Use hard reflective panels above the speaker and position absorbent surfaces opposite the speaker.
Domes, rotundas or cradle vaults have strong focal points and normal sound can be heard as powerful echoes. In order to limit this effect place the focal point high over head or treat the surface with sound absorbing finishes to eliminate reflections.