25 Oct
2005
25 Oct
'05
11:56 a.m.
On Tue, Oct 25, 2005 at 08:38:18AM -0500, Richard Smith wrote:
I haven't found any RIAA filters yet so I guess
I'm looking at
writeing one. So does anyone have any information on where to find
the official RIAA curve to make a plugin from?
The curve as used in most preamps is the combination of
two filtering operations:
- a -6dB / octave filter (i.e. integrator) to compensate for
the velocity response of a magnetic pickup,
- the real RIAA curve.
Combining the two gives a filter like this:
(use a monospaced font to view this)
______
\
\
\__________
\
\
\
\
The corners are at 50, 500, and 2120 Hz IIRC.
Slope is -6dB / octave, so the weighted sum of two
first order lowpass filters is all you need.
--
FA