I really appreciate your great help and great tips.Thanks,Victor Garcia
According to the product information, the Rockford RFQ-5000 is a surround sound processor that will take encoded or un-encoded 2-channel signals and convert them to discrete 5-channel surround. For instance you can play a regular stereo CD and the RFQ-5000 will derive the five main channels. Or you can play a DVD encoded in AC-3 surround and it will be played in five channels.
The RFQ-5000 is a unique device in that it works as in analog rather than as a Dolby Digital 5.1 decoder. This means that you will have regular stereo RCA input connectors rather than a fiber optic or coaxial bit stream input. For this reason you can connect an equalizer either before or after the RFQ-5000 and it will play, but only one way is really correct.
Many would be tempted to connect an equalizer to the input of the RFQ-5000, since you would only need a single stereo EQ (or two, if you chose to use both the front and rear inputs). Connecting the EQ this way will lead to the possibility that the RFQ-5000 cannot optimally derive five channels, since frequencies are being artificially modified before the input. In other words, if the RFQ-5000 "sees" a weird signal coming in, it will probably mess up the conversion to five channels.
The rule of thumb for optimum performance of a processor is to place a non-filtering processor before an equalizer (meaning that a crossover would go after the equalizer). The downside here is that you would require 2-1/2 stereo equalizers, or a 4-channel and a mono equalizer to cover all five of the full range channels. I am not sure if you want to invest that heavily. You can get away with not equalizing the rear channels, but that will still ideally require three channels of equalization.
If you already have a 2-channel equalizer, you can try it before the RFQ-5000 and carefully listen for any weirdness. Each product combination is different, so a little experimentation can reveal interesting things about a product's capability and operating range.