If 60 dB SPL equals how many dB IL?

The relationship between sound pressure level (SPL) and intensity level (IL) can be understood through the formulas relating these two concepts. Specifically, when measuring in decibels, intensity level is calculated using the formula:

[ \text{IL (dB)} = 10 \times \log_{10}\left(\frac{I}{I_0}\right) ]

where ( I ) is the intensity of the sound and ( I_0 ) is the reference intensity.

On the other hand, sound pressure level is determined by the formula:

[ \text{SPL (dB)} = 20 \times \log_{10}\left(\frac{p}{p_0}\right) ]

where ( p ) is the sound pressure and ( p_0 ) is the reference sound pressure.

When calculating the equivalent intensity level from a given SPL, there's a known conversion factor. Specifically, since sound intensity is proportional to the square of sound pressure, the conversion from SPL to IL can be achieved using the relation:

[ \text{IL (dB)} = \text{SPL (dB)} - 10 ]

Therefore, if the SPL is 60 dB, the