Sound Pressure Levels & Ambient Noise

For any system to be effective, the speakers must operate above the ambient (background noise) level of the respective area. Ideally this should be a minimum of 6dB, up to an ideal of 10dB higher than ambient sound levels in the location to be covered. Some typical example levels are shown below.

Typical background noise levels in dB(A)


  Ambient Noise dB(A)
Lounge 70
Toilets 60
Entrance Lobby and Lounge 73
Conference Room 70
Speciality Restaurant 65
Cultural Centre 70
Bar Lounge 65
Meeting Room 70
Health Club - Aerobics 75
Health Club - Internal 68
General Office 50
Restaurant/Canteen 65
Call Centre Office 67
Mainline Station Platform 75
Football Match Crowd Noise 95

At any listening position above, the optimum PA level needs to be 6-10 dB higher. On large system designs where performance is vital, it is important to factor in the loss in dB over distance to ensure the speaker produces enough output to compensate for the distance.

Eg. Factory with a ambient level of 72dB(A) Ideal PA level at the listener is say 80dB(A) Speakers need to mount 8m away from the listeners on structural steelwork. Loss over 8m is 18dB Therefore the level required at the speaker needs to be a minimum of (80+18) = 98dB(A).

Choose a speaker capable of producing this level by checking information on the manufacturers datasheets or speaking to your dealer.