Have you made any changes to the sound system, like changed or added a woofer? If so the Active Noise Cancellation (ANC) can cause the speakers to buzz. Note that the ANC works even when the sound system is turned off. Perhaps the ANC is faulty.
"...all CR-V models now come with Honda's Active Noise Cancellation (ANC) system. This uses a pair of microphones placed in the cabin to pick up low-frequency engine noise, which it then cancels out with signals played in antiphase on the stereo."
www.hondainfocenter.com
As noted in various threads, you have to disconnect the ANC module to turn it off. Here's one thread:
www.crvownersclub.com
"...all CR-V models now come with Honda's Active Noise Cancellation (ANC) system. This uses a pair of microphones placed in the cabin to pick up low-frequency engine noise, which it then cancels out with signals played in antiphase on the stereo."
Honda Information Center - Shared Technologies

As noted in various threads, you have to disconnect the ANC module to turn it off. Here's one thread:

How do I turn off the noise cancellation on CRV 2018?
We should be given an option to turn this off. Can Honda unplug physically for me?