So I decided to pull the trigger on a mini hifi unit I've been looking at for a few months. It's the Yamaha MCR-N870D... it's basically a mini component system put together by Yamaha with a Network CD player (CD-NT670D), Amp (AU670) and bookshelf speakers (NS-BP401). I was previously using my Yamaha YSP1600 soundbar and Cambridge Audio Aero 9 powered sub to play music. Now, I really love music, I am a big fan of Yamaha Musiccast and being able to use Tidal streaming with it but I am no means an audiophile or even close to one... as you will see from my questions I was planning on using my Aero 9 sub with the soundbar and hifi, obviously one at a time. I set the hifi unit up and connected it to my sub via the LFE input as it was with my soundbar... and it sounded absolutely horrible! I was pretty sure it shouldn't sound like that so I consulted the sub's manual and it advises to connect pre-out (RCA) to Line input (RCA) when connecting to hifi. Now my first question is if the amp has a dedicated sub out (single RCA) should that be preferably used instead of the pre-out coming from the Network CD unit? Not having any stackable RCA cables to hand I was not able to try the sub manual's set up as there is only one pair of RCA outs and that is being used to send audio to the amp. The only thing I could try was the single Sub cable from sub out on amp to one of the RCA inputs (red) on the subwoofer. It sounded a hell of a lot better after trying this and more like how it should sound. Question 2 is should I actually connect my sub this way (sub out to single red RCA input on subwoofer)? And is this connection representative of what the system will sound like if I connected it as recommended (RCA pre-out to RCA input on sub). Will it sound better if connected as recommended? The other question is about Pure Direct. I've read many articles claiming it is the bee's knees but it just sounds very plain and flat to me. The music I was playing was VMA lossless files via Musiccast. I preferred leaving Pure Direct off with the bass and treble tuning a bit higher than "central". Am I missing something with Pure Direct, not doing something correctly or is it really just a very subjective feature? Any help would be greatly appreciated. Thanks.