%%HP: T(3)A(D)F(.);
\<<
  IF 'fc\>=4000'
  THEN
    \<<
      IF 'fc\>=8000'
      THEN .65
      ELSE fc 4000
- 1000 / .05 * NEG
.85 +
      END
    \>>
  ELSE .85
  END '\Gb1' STO
\>>
