A Check Airman reports on his first experience with RAAS.

Narrative

Some RAAS feedback on my first flight with RAAS. Because of previous report's about RAAS; on taxi out; I had asked my First Officer's to listen and try to determine which speakers; one or both the annunciations were coming from; due to the feedback of being too loud. As we taxied out to 28L on F; approaching 1L RAAS made the callout; 'approaching 1L;' not 'approaching runways;' then 'on 1L;' but as we crossed 1R; no callout was made; either approaching or on that runway. I checked with the other guys; and nobody heard any reference to 1R; neither an approaching 1R or on 1R. I assume we should have heard something. We were definitely less than 40 KTS. Also in our case the voice came just from the upper back speakers; and volume was not too loud; but just as was discussed at the Check Airman meeting when RAAS comes on at the same time as the clearance from ATC; I can see how it can confuse the issue; trying to hear; listen; and understand two sets of voice commands if they occur at the same time.