The San Francisco 49ers had three practices inside Levi's Stadium. Two of them were used to figure out the noise (or lack of noise) situation. During Wednesday's practice, you could hear the artificial crowd noise being pumped through the stadium's sound system as the 49ers practiced on the field below.
With no official league guidelines set yet, head coach Kyle Shanahan was trying to figure out his options. It sounds like at least some of his efforts may have been unnecessary.
Tom Pelissero of NFL Network reported that the NFL informed teams on Thursday that it will provide a pre-recorded loop of crowd noise, which will be played over stadium sound systems in empty or partially-filled venues. The recordings will be specific to each team's stadium, too, so the 49ers may not have a say in how it sounds. The NFL also dictated that the volume must be set at 70 decibels starting at kickoff.
The NFL informed clubs it will provide a loop of pre-recorded crowd noise specific to each team's stadium that must be played over the PA system in empty stadiums -- and partially filled stadiums, at least to start the season -- at 70 decibels starting at kickoff, per sources.
— Tom Pelissero (@TomPelissero) September 3, 2020
Shanahan said on Thursday during a KNBR interview that the 49ers did practice with the stadium sound set at 70 decibels, and coaches were unable to hear the people next to them.
There is also the issue of hearing constant noise at the same decibel level for over three hours, which can play games with your head. That wouldn't present much of a home-field advantage for San Francisco.
The 49ers also practiced without any noise, which until Thursday seemed like an option. Shanahan didn't like that either. It was the opposite with quarterbacks able to hear the defensive play calls and fans perhaps being able to hear a colorful metaphor slip from a player's — or Shanahan's — lips.
For now, it sounds like there will be pre-recorded crowd noise when the 49ers take the field against the Arizona Cardinals at Levi's Stadium on September 13. How it sounds will be entirely determined by the NFL.