It's a tactic that's been used in the NFL mostly, pumping crowd noise through the speakers to make the home team crowd sound louder than it actually is.
Has it happened in the NHL?
Possibly.
If you ask Boston Bruins forward Brad Marchand, yes and you can find it in Vegas.
When asked by NESN about the loud crowd noise, especially before puck drop, Marchand had a pretty interesting response.
"They just have louder speakers than everybody else. That's all it is"