For routine level calibration, the RadioShack analog SPL meter is the standard. In fact, movie dubbing stages use this very meter to do their calibrations! For more in-depth analysis, there are many RTA applications available. A good measurement microphone can be fashioned for a reasonable cost with a mic capsule from Digikey electronics. The required preamp is easy to construct.

For really accurate calibration of levels, full bandwidth pink noise should be used. This is available on the Avia DVD test disc. The problem with the "test tone" in preamps like the 950 and on most test discs is that they only exercise a very narrow slice of the audio spectrum. This makes frequency response of the speakers at that particular frequency a determining factor in the ultimate calibration. Full bandwidth pink noise averages the entire audio band and allows a more accurate calibration. This is how it is done professionally.