I have calibrated my receiver and speakers for the first time.The reason I did it was people keep asking me how loud do you listen to movies. SVS subs asked me and so did people on this forum. I also often read posts from people who say they listen at -10 to -15 dB. Others says that's way to loud and they listen at -15 to -25. I have frequently been asked how I can listen to Pearl Harbor at negative 10 dB with out being blown out of the room? I thought we were all talking about the same volume level.Of course you would have to take into account the size of the room, whether it had wall to wall carpet etc. but that's not what I'm talking about.I'm referring to the volume level of the sound output by the receiver and speakers. Now I'm being told, by some apparently knowlegable people, that(assuming proper calibration)the output at reference level would be the only volume that all could reliably compare.They say that once you start turing down the master volume level the volume output will vary depending on your receiver. So -15db is not the same on all calibrate receivers.Another poster wrote: It is important to remember that the volume indication on any amplifier reference or not when marked in decibels, indicates level relative to the amplifier's designed maximum gain, not to reference SPL levels or any sound level. While you can calibrate for a given SPL at a particular volume position, you can't expect the two scales (dB SPL vs. dB gain) to correlate exactly. So, -15db indicated could actually be 30db quieter then your reference calibration and -15db on a 1000 watt amplifer vs -15db on a 100 watt amplifier are two totally different SPL levels as well, so we can't actually compare very easily unless we're all using amps with the same gain. The real reason for calibrating (on systems with sufficient power) is to hear the sounds at the levels the director intended (when played at reference level only). He went on to say that only reference level is reliably comparable.Once you start decreasing the Db level then numbers such as -15 or -20 can't be compared. That would explain why some people say they listen at -25 and I would find that to be an extermely low level. Maybe it's not a low volume on his receiver or pre/pro/amp? The only reason I ask whether others agree with this is that, if it's true, I will take peoples listening volume preferences less seriously. If -10dB on a properly calibrated system is not comparable for all then why give your listening levels and have people say "wow that's loud".