How to set up REL Subwoofer?

If you want to use High-Pass you should wire the speakon connector to the front L & R speaker posts. This will send the exact same signal to both the main speakers and the sub. Since both receive the same signal at the same instant in time, there is no phase loss as there is whenever the signal is sent to any additional processor - such as your receiver. If your Cary processor is setup as most 'n.1 or n.2' processors, then you have probably identified the front speakers as 'small' to indicate that you want all low frequency content directed instead to the processor tonvert it into a stream to output to the subwoofer output jack. This means that technically, you would have a superior signal path that preserves precious phase and time values but your sub would rarely or never see anything to play.

The only time it makes sense to choose to wire your sub to the binding posts of the amp is when you have all the signal going to the amplifier and the system has high enough resolution that phase distortion is audible.

Hi!
I just purchased a used REL Q150E sub without the high level Neutrik Speakon cable.   Anybody have one for sale?  
OR
information on
1) which model Neutrik Speakon connector to buythe correct wiring diagram and...
2) wiring diagram
Thanks people!!

 Google "REL subwoofer cable". The sound quality of the stock cable that comes with the REL subs is "meh". REL evens sells an upgraded cable. I have tried several and the best sounding REL cable is from Synergistic Research. 

Dave

Sakahara, as per your original question and not sure why your considering the Speakon connection. 

If you are using this subwoofer with a Home Theater receiver (Amplifier/ Processor) with 5.1 or as they refer it as a "multi-channel system where a .1/LFE signal is present" The receiver will have a (subwoofer) RCA output that is usually crossed over at 80Hz and should be an acceptable match with your current speakers.

Be advised, many powered subwoofers offer high level (speaker/amplifier) connection as an option for those who haven't a second set of preamp or subwoofer output/s. REL is one of the very few if not only sub that uses high level connectivity as a preferred method. 

If your receiver has any room correction it might help with the gain, equalization, and or time delivery of the subs output. The high level connection may not be affected by the receivers room correction.

In any event good luck and have fun eith the deep state.

[["REL R-Series Manual UK 02/06

.1/LFE input connection using a phono to phono interconnect (Note: This connection is for the .1/LFE channel and should only be used if the REL is being used in a multi-channel system where a .1/LFE signal is present, e.g. with DVDs or SACDs)

.1/LFE INPUT

Phono Interconnect

To Sub/LFE output of Amplifier/Processor

Connect as shown above. Plug one end of the interconnect into the Sub/LFE output on the amplifier/processor and the other end into .1/LFE INPUT on the Sub-Bass System.

The output level is adjusted using the control marked .1/LFE LEVEL"]]

I have two REL T5 subs, one for each channel (HIFI stereo listening only)
what is the correct cable set up with the Neutrik cable/s. 
I am guessing its (+)sub to (+)amp and (-)sub to (-)amp and the earth to the amp chassis? for each channel? Do you think this is correct? 
Thanks in advance