If the intensity level of one trombone is 70 dB, calculate a reasonable estimate for the intensity level of 76 trombones all playing simultaneously in the same place

 β₂ = 88.8 dβ

Explanation:

The intensity of the sound is

        β = 10 log (I / I₀)

The sensitivity threshold (I₀) for humans is 1 10⁻¹² W / m²

       I = I₀  

       I = 10⁻¹² 10^{70/10}  

       I = 1 10⁻⁵ W / m²

The total intensity for the 76 trombones is

         I_total = n I

         I_total = 76 1 10⁻⁵

         I_total = 76 10⁻⁵ W / m²

Let's find the sound level

       β₂ = 10 log (76 10⁻⁵ / 10⁻¹²)

       β₂ = 88.8 dβ

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