You can just simply play a music file using your Media player and set your AVR to 2 channel stereo. Let the AVR do everything except playback(New AVR can play music files, i'm not sure about yours). Try also setting your speakers to large while playing music and listen to how it sounds.
I have two setup HT and Pure audio, one new member visited me simply because he wanted to Audition and Learn how to setup an HT. He also asked me about why people setup dedicated HT and dedicated audio, he asked me because ang dami nya daw nabasa na "iba daw talaga ang separate Audio setup kesa HT setup when it comes to SQ for music"
So, i let him experience listening to two channel music on both my HT and Audio Setup. Then sabi nya, pareho naman palang maganda for music eh, well sabi din nya na newbie sya and not really an audiophile with experience in critical listening. He just want to enjoy the Music but para sa kanya ok na sya dun sa SQ ng HT setup for music.
Anyway, my point is. Like what synchro said, experiment on your HT for music... Iwas gastos pa