As social distancing measures around the world begin to increase again and the NFL begins to kick off for the system, the NFL is implementing a system to fill its audience-free and partially filled stadiums with pre-recorded audio, providing a loop of specific crowd-related sounds during games.
The audio will be broadcast at 70 decibels from kick off until close of play, with NFL staff monitoring the audio throughout the game to make sure that crowd noise does not exceed or go below the required decibel level.
Club-specific audio pallets were created by NFL sound engineers, with the sounds able to be changed to create a dynamic and fluid crowd atmosphere, with music and audio prompts such as train whistles and foghorns only able to be played by club game presentation personnel up to a certain decibel under NFL supervision.
Pre-recorded crowd noise has been produced which is specific to each stadium, creating an audio backdrop to mask field-level audio typically not heard in a stadium environment.