The 50Khz 'Neumann Pole - CH P10 User Manual

4.3 The 50kHz 'Neumann Pole'

In addition to the two zeros (turnover frequencies) and the pole normalized in the RIAA (or other)
pre-emphasis curve used in cutting records, in practice production plants had to stop the ever-increasing
gain at high-frequency above the audio band in order to prevent cutting equipment from overheating and
cutting heads from ringing. This was done in various ways, but generally involved adding a second, high
frequency pole to roll off the extreme high end – normally at around 50kHz. It was a technique used by
various different lathe manufacturers, but became known as the "Neumann pole". Adding the 50kHz pole
to the pre-emphasis curve suggests the use of a corresponding 50kHz zero in the de-emphasis/replay curve
– often referred to as the "enhanced-RIAA" or eRIAA curve. The P10 allows users to add the 50kHz zero for
any disc or curve on a record-by-record basis.
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