What is the best DB level to

Get yourself a SPL meter. It's the essential audiophile accessory. First use it to balance your HT system. Then use it to spot check your typical listening levels. Your personal preferences will come heavily into play. Personally, I find 85dB at the listening position to be quite loud for all types of music. A good system, properly setup should sound good at both loud and soft levels.

Sean, as always a most illuminating post. I listen to a wide variety of music and in a 33 by 14 room the typical listening levels are in the 70-80dB range. The music is loud enough to impede normal conversation. Even when cranking up the volume I rarely go above 90dB, but it's not because of any nastiness or distortion creeping into the sound at higher volumes. I suspect I am like many who simply don't have the need to listen any louder. It's a personal preference. For myself - via airplanes, motorcycles, small engines and trains - I have more than enough exposure to high decibel levels. Listening to music is refuge from that loud world and as a result I only like my music a little loud.

One point in closing. A tough test for any system is whether it can convey the impact and intent of music at very low volumes.

The following link will take you to part of Galen Carol Audio's website and will display three sound pressure level charts.

http://www.gcaudio.com/Archives/loudness.htm
Pain begins at approximately 120-125dB, but hearing damage can result from constant exposure at 90-95dB. Specifically, the OSHA regulations prescribe that sound levels above 105dB are limited to less than 1 hour per day. If you have pets, remember that cats and dogs have more sensitive hearing than humans and their hearing can be damaged too.

Loud music can be most pleasurable, but it is not without its downsides. Common sense is advised.