Knowledge Centre · Understanding Noise
What is Sound Pressure Level?
Sound Pressure Level (SPL) can be thought of as a measure of how loud a sound is, expressed in decibels (dB) — one of the most fundamental measurements used in acoustics.
Read time
2 minutes
Relevant to
Anyone reading a noise report or condition
What Sound Pressure Level (SPL) stands for
SPL stands for: Sound Pressure Level.
Fortunately, it is much simpler than it sounds.
Sound Pressure Level (SPL) can be thought of as a measure of how loud a sound is, expressed in decibels (dB) — one of the most fundamental measurements used in acoustics.
A changing sound level, measured in decibels
Sound is created by tiny changes in air pressure caused by vibrating objects. These pressure changes are extremely small, so they are measured using a logarithmic scale called decibels (dB).
As sound levels constantly rise and fall, the Sound Pressure Level (SPL) changes as well. Acoustic instruments measure these pressure fluctuations and express them as decibel values, providing a consistent way to describe how loud a sound is.
Many familiar acoustic descriptors—including LAeq, LAmax, LA10 and LA90—are all based on measurements of Sound Pressure Level.
If you measured the noise from a generator and recorded a Sound Pressure Level of 75 dB, this means the sound pressure at the measurement location was equivalent to 75 decibels at that moment or over the specified measurement period.
Where is Sound Pressure Level (SPL) used
Sound Pressure Level is the foundation of almost every type of acoustic measurement.
Typical applications include:
- Environmental noise assessments – measuring noise from industry, transport and community activities.
- Occupational noise monitoring – assessing worker exposure to hazardous noise.
- Building acoustics – assessing sound levels within and around buildings.
- Product and equipment testing – measuring the noise emitted by machinery, appliances and industrial equipment.
- Research and acoustic investigations – providing the basis for detailed acoustic analysis.
Related reading
Try the calculator
See how multiple sound levels combine logarithmically, not by ordinary addition.
Talk to us
Send the brief, the drawings, or just the problem, we will come back with a clear, fixed-scope proposal.
Need an SPL measured or assessed?
Send us the address, drawings and application type, and we’ll come back with a proposal, usually within two business days.