In daily lives, we often experience a phenomenon called the "masking effect" which makes certain sounds hard to hear or makes them completely inaudible.
To minimize this kind of phenomenon with your sound system, the Sound Pressure Level (SPL) should always be higher than the ambient noise level at the installation locations.
Chart: Ambient Noise Level and Common Environment
Here is a basic guideline on the difference between the required SPL and the noise level for different applications.
a) Voice communication Generally, the speaker's SPL should be at least 6 dB to 10 dB higher than the ambient noise level.
b) Background music The speaker SPL should be 3 dB higher than the ambient noise level.
c) Music performance Unlike a) and b) above, the speaker SPL should not be referenced to the level of local ambient noise. The ambient noise level in an area where music is performed should be under the lower limit of the SPL range of the music. For example, if the upper limit of a pop song is about 95 dB and the lower limit is about 35 dB, the ambient noise level of the location should be lower than 35 dB. In other words, the location for music performance must be relatively quiet in itself. If you need any assistance with public address or background music system design, we are happy to help you.