I found that when using test signals standing waves are much more noticeable. In my case in the mid-band moving my head from side to side made a dramatic change in the level. It's quite likely that the meter is reading correctly and your ears are hearing correctly, it's just that they are in different locations! With respect to the RS meter being inaccurate, yes it is but more so in the lower regions. In the mid-band its within a dB or so, close enough for what you're using it for. Rives does make a test CD that corrects for the meter if you don't want to do the math yourself.
Good uses for a sound pressure meter?
I bought the $50 Radio Shack digital meter to help with Sub integration using the Stereophile/Chesky test CD. Can't say I was that impressed with the resulting setup and just adjusted by ear. One thing I did notice was this. In the test for "spurious resonance" it starts with high frequency and progresses to low. When I heard fairly dramatic volume drops in certain middle freq. ranges I assumed it was the speakers but when I set up the meter and recorded the db levels there was no drops of significance during those parts . This makes me think that I 'm the one with a crummy frequency response. Comments? Also, if you have any other good ideas for SPM use, let me know. Thanks.