I just picked up my 70D yesterday (6/6/15). I ordered the upgraded sound without ever hearing it. When I pickup up the car, I played with the audio controls. I was surprised that $2500 only gets you a 3 channel equalizer and L/R, F/R fader controls. The front speakers sound full, but when I pushed the sound to the back, it literally sounds like a cheap transistor radio is playing in the trunk. I looked at my DS and asked him if something was broken. He said he didn't think so. I'm no audiophile, but I think the sound is decent if I set the fader in the front or middle. Any comments from the group? Is this normal? Is my audio system broken? I've search the web but can't find any discussion on this. Frankly, I'm disappointed.