Try using the 5.1 or 6.1 "wide band pink noise" tests on the Avia test DVD. Wideband pink noise is a very sensitive way to hear changes in frequency filtering and levels. The test tone internal to the 950 is filtered pink noise with it's energy centered around 1,000Hz. There is no bass energy to speak of on this test signal. As far as I know, the Avia disc is the only one that has wide band pink noise, but I could be wrong.
If you use the Avia pink noise for calibration, be aware that you calibrate for a sound pressure level of 85db instead of the 75db that is standard elsewhere.