I disagree with most everything Minorl says.
Keep it all on one leg. It matters. It not about the noise. If you have a good system, say AR Ref amps and an Esoteric CD player, you will hear it. It will be more clean and clear. If you have a Cary SLI80, you might not hear it. But you will still notice a 10AWG dedicated circuit vs a 12 AWG feeding the rest of the living room.
I also have not been able to validate putting lights or motors on the same leg as audio is detrimental. The noise is also on the neutral. You can’t hide from it. I have tried this on many systems before I gave up on it because no one ever heard it. Make sure to use a quality dimmer such as a Lutron Maestro. That will filter most of the noise. I do put motors on a separate leg to reduce startup voltage sag on the audio phase.
I do like a good filter. But the only one I have found to work to my satisfaction is a large Torus transformer that has everything on it. Including your modem, router and switch if you stream. I don’t like most other filters. They either collapse the sound stage or create an artificial "Black".
If you don’t want to filter your audio, you segregate your power with subpanels and you filter the noise from your house. But what are you really doing. Not much unless your off grid "Island". And if your off grid, I am still going to suggest you put a Torus onto the circuits feeding the audio to filter the inverters high frequency noise. As well as any RF that is attaching to the power wiring. If RF is attaching to the phono cartridge, tone arm wire or case of the phono stage itself, you cant do much other than get a good phono preamp that is good at rejecting the noise and not letting it modulate into the power supply.
If you happen to have a very large estate with pools and fountains, security systems, a server farm and a high end audio system, then segregating power and filtering the noise from getting back to the audio becomes something to consider. You probably have a dedicated utility transformer so your filtered from the street noise. You may want PFCC attached to a subpanel feeding the motor loads. You may want a UPS attached to the server farm and security system. You may want critical power with battery backup for light and refers in power outages. Most people don't have this. They share power with 5 neighbors on one transformer. Your getting all the noise from their dirty devices. So trying to segregate and filter your own dirty devices is a loosing battle. Your best option is to filter the line to the audio equipment.