Well I just tried the (ND) Noise Destroyer on the wall duplex outlet with the Hydra 8 plugged into the other ,and the Sony HD is still plugged into the first outlet in the Hydra 8.
The result: HD TV not as good as plugging the ND into the first duplex outlet in the Hydra with the Sony HD plugged into the other.
The difference is quite remarkable.
Perhaps the improvements I am seeing is with the Sony HD and the Hydra outlet being isolated from the other outlets, in the Hydra 8 it is concentrating all the ND energy into that one duplex outlet.
So,one ND will remain in the first outlet on my Hydra 8 and my other ND will go into the wall outlet that my APL 3910 is plugged into.
I plan on purchasing a couple more and will play with additional placements with my Amp outlet, etc.