I am getting and buzzing/interference sound from my Tivo. This can sometimes be cured by restarting. It does not seem to occur watching TV, but watching recordings or other apps like Netflix or catch up TV.
Welcome to our Community and thank you so much for your first post; sorry that your box is being louder than it should.
It is to be expected that there will be more noise when watching recordings as the box is actively using it's internal tuners. However, from looking at your account (located from your Forum information) I can see that you have since been in touch to report the issue and we have booked a technician for you.
I do hope that all goes well with the visit - please do keep us posted with how it goes.