Rat Shack SPL meter: Analog or Digital?

Rives, is that why your calibration is different than the one at Audio Asylum?
A-A calibration

If I'm not mistaken the one at Audio Asylum is a general C weighted correction. C weighting is not flat, and this curve is published in the Radio Shack manual. However, the Radio Shack does not mimick the C weighting precisely and is a bit worse in terms of linearity. We tested several meters and found they were all very very close. We also tested the meter with Nickel Metal Hydride batteries and regular akaline batteries and found no difference. We did not check Ni-Cad batteries. I believe our results are nearly the same as those published in Sensible Sound (I've been told this, but have yet to see the article--if anyone has a copy I would really like to see it).

Also, we sent our results and a sample disc to Radio Shack. They liked the idea and considered (and even had a meeting on it) marketing our CD. However, the meter is small potatoes to company like Tandy--and our CD--well microscopic would probably sum it up. Too much effort for too little gain for a company like Tandy. But we were happy that they did seriously review it.

Rives,
Can I use your CD with digital meter?

It is not calibrated for the digital meter. We found a fair amount of difference between the digital meter and the analog. The digital is actually closer to linear than the analog, but it was less consistent from various units--it's also harder to use. Our tracks would give you better results than a flat response, but they are not precise for the digital unit. I would recommend getting the analog version.

When I was demoing audio gear, I considered buying one of these to allow me to do a more fair comparison -- apparently it is very hard to set gear to identical volumes, and the louder gear sounds better.

I was told elsewhere, though, that the accuracy of the meters is not good enough to help in this project (I think it's +/-2db?). Is that the opinion here also?

Thanks,

Eric