Kevin Sutton:

>On the back of an old lp of mine (VOX, Debussy Preludes I, Novaes),
>there is a set of care instructions on the back.  One of the items
>says: "For those with wide range equipment, it is advised to adjust for
>the RIAA curve." Would someone please explain to me what this means?
>This collector of old records feels left out of some techno-history here.

This goes way back.  "Wide range equipment" means audio equipment capable
of reproducing the full audible range, 20-20,000 cycles per second (as
they said in those days) without distortion, or on a "flat" curve.  In
other words you could hear the bass as low as it got and at the volume it
was played by the musicians.  (Nice if you can do this today.) With most
equipment then, and with cheap equipment now, there was a big drop-off
below a certain frequency, and in the higher range also.  Now, if I
understand correctly--and there is hopefully someone here with better
knowledge--the RIAA curve (and the NAD curve) changed--in the recording
studio--the recorded dynamics above and below certain frequencies to
compensate for this.  To "adjust" for this--at home--was to set your
controls so that what was in effect deliberate distortion in the record
was removed in the playback.  I was never clear about the formula or
specifics because I was never in a position to do this in those days.

Jim Tobin