The RIAA record curve reduces bass and increases
treble, and the reverse
RIAA curve for playback does the opposite.
Sorry, but this is plain wrong. The RIAA filter used when cutting a disk
master will boost bass (below 50 Hz), and reduce high frequencies. This
actually leads to a worse S/N ratio on playback. It looks like this:
Has a spread sheet that runs the math on the equation presented.
Unless I'm just backwards for RIAA reproduction it yeilds roughly 20dB
of gain for 20Hz and -21dB for 21kHz. Which seems backward from what
you are saying.
--
Richard A. Smith