PVR 721 vs Shielded Speakers

I just purchased a 721 and I am in the process of setting it up. In my entertainment center, my previous receiver (4700) sat next to a shielded center channel speaker on the same shelf. A shielded tower speaker stands next to the entertainment center. Given the 721 has a hard drive, does anyone know or have advice on what the minimum safe distance is between the 721 and these shielded speakers.

The center channel speaker is located directly under a 36" Sony Wega TV. The speaker does not affect the TV, so I think the shielding is pretty good. For the engineers out there, the speaker manual states the speakers are shielded to less than 3 gauss at the surface of the cabinets.

Thanks for any responses.

The Vorlon