How important is EMI and RFI rejection?

Go over to Audio Asylum. Do a search there. He's posted his views many times. Ayre uses double insulated chassis' in their design so you can float the ground without the danger (according to Ayre anyway). Charles also lives in an old home where none of the outlets are grounded. I believe he floats all grounds in his system.

Here's on thread where Charles comments:

http://db.audioasylum.com/cgi/m.mpl?forum=general&n=525276&highlight=ground+charles+hansen

Based on what they're experiencing it appears that floating grounds has similar sonic effects to the Tripoint.

I have found that on my system that consists of Magnepan speakers (20.1) Krell FPB 600 amp, Accustic Arts DAC, Sim audio moon eclipse cd player(used as transport) BAT 52 SE preamp, ps audio power plant premier(ac to dc to ac generator)dedicated breaker box, shielded ac wiring,dedicated sockets, 6 foot ground rod in the earth,that I could not live without cables that were not efi sheilded. When you get cables that are well shielded you will get rid of a glare and blanket of music robbing junk. I use Purist Audio Design cables exclusively. If any one tells you they don't make a difference in performance then they sould talk to NASA and see what they say about EFI and EMI. Better yet do an A,B comparison and you will hear the music come alive. I have enjoyed the improvement for years now and no one can tell me after all the improvements that noise does not enter through cables. Just by nature they are antenas. Also if you want to hear another product that gets rid of EFI andEMI by the power of ten then check out Tripoint Audio you will be shocked.

Thanks for the AA link. I see he's basically saying he prefers a floating ground vs actual ground. I'd say that's fine - most of the time. The goal of good ground design is to get all the equipment at the same negative voltage level. For actual ground this is 0 volts. In a floating ground it can be... well anything really but usually a few millivolts. The main thing is that everything is at the same voltage level. The "usually OK" part is if you really do have EMI/RFI problems. This is because the other goal of good grounding is to shunt excess energy away from the system. In a floating system, there is no where for the excess energy to go. This can still be fixed with a five cent capacitor.

Booboobaer, no one has said well designed cables that shunt EMI/RFI to ground don't make a difference. Or that grounding isn't important. Or that you can't hear a difference. To the contrary, it is all extremely important. It just isn't expensive.

This is because the other goal of good grounding is to shunt excess energy away from the system. In a floating system, there is no where for the excess energy to go. This can still be fixed with a five cent capacitor.
Danmyers (System | Answers)

Danmyers, how would you fix it with a five cent capacitor?

Hi Clio,

Assuming RFI is the issue a .01uF ceramic bypass capacitor connected between the floating ground and real ground will shunt all the radio frequency energy away from the audio system and to real ground.

Dan