Well, I have placed the speakers a little bit 30 cm out from the wall behind. A. Bit of toe-in. If I use the main AVR outputs for all the speakers, I can connect the REL by both methods - a LFE0.1 out as well as additional three wires of the neutrik speakon directly attached to AVR output. If, I buy a separate 3 channel amp, I would have to use the RCA pre-outs to the Emotiva amp? How can I use a power high level output of AVR to the input of the three channel amp? Wouldn’t it be dangerous?
OK I have found the drivers.
The woofers are from a cheap budget line from Peerless. They are available in the US for $50.00 each. They are actually specked as mid woofers. They have an FS of 40Hz. the lowest they will go is somewhat above Fs, in this case ported the F3 is 60 Hz. So they have no depp bass, and are specked by Peerless as mid/woofers. Looking at the Peerless spec. sheet those drivers suffer cone break up starting at 1KHz. So their bandwidth is 60 Hz to 1KHz.
So essentially you have two cheap bass drivers, honestly specked and marketed by Peerless crossed to what is another mid woofer and not a dedicated mid driver, and a Tweeter. The Morel units are quality drivers.
So we have a couple of bass mids with a bandwidth of 60 Hz to 200 Hz, crossed to a mid woofer 200 Hz to 2.5KHz.
That is just not a sensible design and will not sound good whatever you drive them with. That design is a real amateur hour job.
If you want better sound then you need to go speaker shopping.