I tired and tired to hear a difference with the RG 400 unit but to my ears nothing, that being said I know two others who use a Hydra and a Exact Power and they swear by them. There other ways to do this, see some other threads by Sean, Physicanimal and Lak, they have this stuff down to a science. I am following their teachings and trying to do what they have accomplished.
Happy Listening.
Happy Listening.