5 dB SPL (A-weighted) -- not negative, SPL is measured from a 0

that was intended to represent the threshold of hearing in the
mid-range.

>I come from the studio world where all our mics tend to
>be 10 to 15 db quieter than this

(and too delicate for field work)

>& I'm wondering what users of this
>Shure have to report about the noise performance, say, into a decent
>but not superlative preamp (front end of a Sony DAT, maybe) in a quiet
>forest setting.

Exactly my experience. I found them quiet enough for a lot of
soundscapes, too noisy for really quiet places. Good for a beginner
because of the low cost, for a pro as back-ups.

>My recollection of the run-of-the-mill Sony lavaliers I used in the
>80's was that they were simply too noisy for any critical recording.
>Thanks,

The 183 distinguishes itself in the lavalier field by its high output
and relatively low noise. No magic, just a very useful compromise.

-Dan Dugan