Correct positioning of panels

The best choice is usually the ceiling

A ceiling offers sufficient space and is usually the simplest way to position panels. The larger the cavity between panel and ceiling, the better the absorption performance in low frequencies.

Yet there are several points which must be heeded:

The calculated optimal reverberation time may deviate from that actually achieved in the room

1. The calculated optimal reverberation time may deviate from that actually achieved in the room
   • please heed the issue of flutter echoes
2. An optimal reverberation time in the room does not automatically guarantee ideal room acoustics
   • Acoustical demarcation of individual areas within the room
   • If speech must be heard intelligibly over great distances

Flutter echoes:

	a) Unfavourable: two acoustically hard parallel surfaces may produce flutter echoes, for example from a ceiling to the floor, or from wall to wall. This leads to an actual reverberation time in the room which deviates from the calculated reverberation time.
	b) Favourable: placing elements such as plants, shelves etc. and/or tilting surfaces (by at least 5 degrees) can help minimize flutter echoes.
	c) Favourable: Avoiding the flutter echo effect through the use of broadband absorbers (thick line on the graph = absorbers)
	(Source: Fasold, W.; Veres, E.; Schallschutz und Raumakustik in der Praxis, Verlag für Bauwesen, Berlin)

If speech must be heard intelligibly over great distances

a) Unfavourable: important reflecting surfaces are lost

b)Favourable: the requisite reflecting surfaces remain intact. Listeners towards the back of the room can still hear speech easily. Low frequency absorbers (such as R16D1.2ST) only, however, can still be installed towards the middle.