The sound pressure level of
the ambient noise
How should a designer decide the output volume (SPL) of a speaker (SP) ?
To decide how many speakers to install, designers need to know the ambient noise level (SPL of the ambient noise) at the site. Ideally, the ambient noise level should be measured on site. If this is not possible, reasonable assumptions must be made. Common ambient noise levels are introduced here.
To decide how many speakers to install, designers need to know the ambient noise level (SPL of the ambient noise) at the site. Ideally, the ambient noise level should be measured on site. If this is not possible, reasonable assumptions must be made. Common ambient noise levels are introduced here.
Required SPL Varies with Ambient Noise Level
In our daily lives, we often experience a phenomenon called the "masking effect." This makes certain sounds and speech difficult to understand because they can become unintelligible in the presence of background noise.
To overcome this and to minimize its effect, the Sound Pressure Level (SPL) is required to be higher than the ambient noise level.
To overcome this and to minimize its effect, the Sound Pressure Level (SPL) is required to be higher than the ambient noise level.
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 / Announcement
Generally, the loudspeakers SPL should be at least 6 dB to 10 dB higher than the ambient level.
For ceiling speaker design based on this concept, please refer to this page.
For applications using wall-mounted speakers, please also refer to this page.
You can listen to simulated examples of announcements with insufficient volume compared to the ambient noise on this page.
In facilities such as railway stations, ambient noise levels can vary significantly throughout the day as pedestrian traffic changes. Consequently, the optimum announcement level may also change over time. Ideally, the system should be able to adjust its output level automatically, either in response to real-time ambient noise measurements or through time-based control settings, to maintain consistent speech intelligibility. This page introduces methods for automatically adjusting broadcast volume levels.
b) Background music
The loudspeaker SPL should be at least 3 dB higher than the ambient noise level.
However, the required BGM level depends greatly on its intended purpose. In some environments, such as retail stores or themed spaces, the music is an important part of creating the desired atmosphere and should be clearly audible. In other settings, such as restaurants or cafés, the music should enhance the ambience without interfering with conversation. There are also venues such as bars and entertainment spaces where music quality and impact are prioritized, and the audio level may approach that of foreground music rather than traditional background music. Therefore, the target SPL should be determined according to the venue, application, and listening experience required.
c) Music performance
It goes without saying that the output level from the speakers should be higher than the ambient noise, but the SPL of the speakers should not be based on the level of ambient noise in the field.
Depending on the venue and application, the typical SPL for music reinforcement can exceed 95 dB. Ideally, the quieter the venue, the greater the achievable dynamic range.
Therefore, SPL levels should comply with applicable local regulations and hearing safety guidelines. to protect listeners from hearing loss while still allowing them to experience the full dynamic range of the music.
Generally, the loudspeakers SPL should be at least 6 dB to 10 dB higher than the ambient level.
For ceiling speaker design based on this concept, please refer to this page.
For applications using wall-mounted speakers, please also refer to this page.
You can listen to simulated examples of announcements with insufficient volume compared to the ambient noise on this page.
In facilities such as railway stations, ambient noise levels can vary significantly throughout the day as pedestrian traffic changes. Consequently, the optimum announcement level may also change over time. Ideally, the system should be able to adjust its output level automatically, either in response to real-time ambient noise measurements or through time-based control settings, to maintain consistent speech intelligibility. This page introduces methods for automatically adjusting broadcast volume levels.
b) Background music
The loudspeaker SPL should be at least 3 dB higher than the ambient noise level.
However, the required BGM level depends greatly on its intended purpose. In some environments, such as retail stores or themed spaces, the music is an important part of creating the desired atmosphere and should be clearly audible. In other settings, such as restaurants or cafés, the music should enhance the ambience without interfering with conversation. There are also venues such as bars and entertainment spaces where music quality and impact are prioritized, and the audio level may approach that of foreground music rather than traditional background music. Therefore, the target SPL should be determined according to the venue, application, and listening experience required.
c) Music performance
It goes without saying that the output level from the speakers should be higher than the ambient noise, but the SPL of the speakers should not be based on the level of ambient noise in the field.
Depending on the venue and application, the typical SPL for music reinforcement can exceed 95 dB. Ideally, the quieter the venue, the greater the achievable dynamic range.
Therefore, SPL levels should comply with applicable local regulations and hearing safety guidelines. to protect listeners from hearing loss while still allowing them to experience the full dynamic range of the music.
