IANAL, but given that they are doing this in California, I would say Penal Code 135 PC [1], the willful destruction or hiding of evidence during a legal proceeding such as a criminal investigation. Police conduct during an arrest constitutes material evidence and thus the intentional playing of music that they believe will prevent those recordings from being produced or discoverable constitutes a willful hiding if not destruction of said evidence. Such a crime may result in up to 6 months in jail per offense.

[1] https://www.shouselaw.com/ca/defense/penal-code/135/