What is the sound pressure level at 1 meter from a source that emits 90 dBSPL and is measured at 3 meters away?

To determine the sound pressure level at 1 meter from a source that is measured at a distance of 3 meters, we can use the inverse square law of sound propagation. This law states that the sound pressure level decreases by 6 dB every time the distance from the sound source is doubled.

In this scenario, if the sound is measured at 3 meters and the level is 90 dB at that distance, we need to calculate what the sound level would be at 1 meter, which is a closer distance. Since 1 meter is half of 3 meters, moving from 3 meters to 1 meter means reducing the distance to half.

To apply the inverse square law:

1. The increase in sound level when halving the distance from 3 meters to 1 meter is 6 dB (from the 3-meter reference point to 1 meter).

2. Therefore, you add 6 dB to the original 90 dB measured at 3 meters, which gives:

90 dB + 6 dB = 96 dB.

However, the correct approach for understanding the options provided involves calculating the decreased distance effect from the stage at the first point of measurement (usually taken