Question about sound levels

[MouseRider]

For theater sound, the volume known as the "Reference Volume" is defined at 105db peak signal from all channels.

What that means is when your preamp/receiver is set to 0db attenuation, the peak sound pressure coming from each of your speakers should be 105db at your listening position.

Most calibration tones on discs and built-in are usually set to be at -30db, so if you are using an SPL meter to measure the sound pressure from your speakers, they should all read 75db.

You can get one of these meters pretty cheaply at Radio Shack.

If you do that and set your receiver/preamp to 0db attenuation, you will be listening to the soundtrack at the levels it was mixed in the mixing theater.

Depending on your room setup, this might be too loud but once you have it calibrated, you can lower the volume and your receiver/amp will do it proportionately.

Some lower-end receivers don't indicate proper attenuation levels but use an arbitrary "volume number" instead, if you have that problem, you'll have to pick a number and stick with it and hope the your system has a volume scaling system that is equivalent to the log scale of db.