In reality, store spaces are full of noise.

You may not think that your store space is noisy, but in this context noise includes the voices of customers/guests, employee noise, and sounds from the kitchen or equipment, for example.

Collectively, these sounds are referred to as background noise, and serve as an important indicator for determining the optimal volume for delivering music. In general, the music volume in stores should be at least 3 dB higher than the background noise level.