Out of control bass--help

I recently got an Anthem AVM-20 to replace a old Onkyo receiver that I was using as a processor. The other players in this mess are a Sunfire Cinema Grand and a REL Storm III. Basically, doing nothing but swap processors, my bass is overwhelming and there is a huge 50Hz problem in particular. I'm assuming the source of this problem is largely my lack of knowledge. I've never had a processor with a built in crossover.

I have my REL connected via high level with a Neutrik connector from the amp and low level RCA from the preamp sub out. Leaving the sub crossover settings exactly as they were prior to the Anthem and bypassing the pre/pro crossover, the bass was way too much. I don't have a meter, but using a Rives test cd, 50Hz is clearly the major culprit. I then tried using the anthem crossover and set the REL crossover to the highest setting with no noticeable difference. I also used the notch filter setting on the Anthem at 50hz and cranked it all the way up to 10db with no difference.

Some other issues that I find strange:

When playing the Anthem test tones, they only play through the sub, not through the front speakers. Am to assume that the notch filter only works on the sub then? Is the processor ignoring my high level connections to the REL? My fronts are Vienna Acoustics Beethoven's rated down to 30Hz so I really don't want to set a high crossover on them.

I'm stumped here. Any input would be greatly appreciated. Everything sounds great until the bass notes...
Well, first things first I guess...Should I be using the Anthem crossover or the REL crossover? Does the Anthem crossover apply to both high and low level REL connections?
I suggest you download the Manual from Anthem Website.

You have the ability to control the individual level sent to each speaker including the sub. It sounds like you need to adjust the levels first and then play with the crossover.

The notch filter only works on the sub....so it is probably your REL Storm which is getting too high of a signal (wrongly connected). Connect the second sub to the sub 2 XLR jack with subwoofer set to "2 sub" or "2 super" 9see page 45 of the manual). Recall that with speakers set to "FULL then "2 Super" takes all the LF channel information and combines it with the LFE channel and sends it all to the sub. If you are watching a movie the "2 Sub" setting will be better (Cinema configuration) for stereo you may want to use "2 Super"

Anthem AVM 20 Owners Manual

Good Luck