Have you tried NOT using the REL subwoofer? Since it's a very small room you could be overloading the room with bass. The Prima Luna might not be the best match for your trio of speakers. A leaner/faster sounding amp(Bryston 135-Krell 400ix-Primare 30/31) and faster(better) cables(Nordost/JPS)could clean up the mid/upper bass of your speakers.
My stereo isn't doing it for me. Need advice
I have been trying to get a great sounding room for a while now and it still doesn't sound great or even good. I have a Prinaluna Dialogue 5 power amp and a Primaluna Prologue preamp. All with stock tubes so far. A Marantz c6005 CD player. Morrow mc3 interconnects and Kimber 8tc speaker cable. My speakers are Dynaudio x12's which sound the best in my room. I also have Dynaudio x32 speakers and a pair of KEF LS50 speakers. Also a REL T-5 subwoofer. My room is my office and is 9 x 11 with 8 Foot ceilings. Some acoustic stuff sounds great but the louder stuff not so much. I find I listen to music that sounds good rather than music I want to hear. Any suggestions on what I can change. I also bought a Class D Audio 200 watt per channel amplifier that makes everything sound even worse.