i have the system set up for almost 3 weeks now.. it sounds great. however, I need to crank up my receiver volume to -15db to get a "kick" out of the audio.

is this ok for the receiver to run long term at 90% of the volume like this?..

should i get an external amp? i've seen a lot of good review on emotiva xpa-5. Can i use my receiver only for the 2 rear speakers and use an external amp (ie. emotiva xpa-5) for the remaining 5 speakers?

thanks in advance for your feedback.. I am still a newbie in this area.

HHP

It would appear that -15 is more on the order of 2/3rds of the maximum setting, not 90%. In any case, it certainly isn't unusual and is no cause for concern.

Your Denon will be playing at reference level when your dial is at 0dB, but should go to about +20dB. I listen to all my movies between -15 and 0dB.

All good. I wouldn't worry too much unless you were regularly in the "pluses". I usually watch movies from -10 to 0. Any lower and the couch doesn't shake enough

I have the same receiver and I use an external amp for the two fronts. It does make a difference in loud action scenes.