GET EQ CURVES WITH YOUR
RIAA PREAMP AND A GRAPHIC EQ

Here is how to get old recording curve playback with an RIAA preamp and a graphic equalizer. Read the CODE portion, and look for the parts here. Then plug them into your equalizer:

Code 20Hz40Hz62Hz100Hz200Hz400Hz620Hz 1KHz2KHz4KHz6.2KHz10KHz15KHz20Khz
800N -? +10+8+6+4+4+3+2 0*???? ??
800C -? -4-1-0+2+4+3+2 0*???? ??
630N-? +8+6+4+2+2+1.5+1 0*???? ??
630C-? -4-2-1.5-0+2+1.5+1 0*???? ??
500N-? +6+420000 0*???? ??
500R-? 0000000 0*???? ??
500B-? -6-3-2-1000 0*???? ??
500C-? -8-5-4.5-2000 0*???? ??
400N-? +4+20-2-2-10 0*???? ??
350N-? +3+1-1-3-3-1.5-.5 0*???? ??
350C-? -9-8-8-5-3-1.5-.5 0*???? ??
300N-? +1.5-.5-2.5-4.5-4-2.5-1 0*???? ??
250N-? 0-2-4-6-4-2.5-1 0*???? ??
200N-? -2-4-6-8-5-2.5-1 0*???? ??
?-16 ????? ?? 0*-1.5-2.3-2.3-2.3-2.3-2.3
?-15 ????? ?? 0*-0.8-1.3-1.3-1.3-1.3-1.3
?-13.7 ????? ?? 0*000000
?-12.7 ????? ?? 0*+.5+1+1+1+1+1
?-12 ????? ?? 0*+.8+1.7+1.7+1.7+1.7+1.7
?-10.5 ????? ?? 0*+1+2+3.2+3.2+3.2+3.2
?-10 ????? ?? 0*+1.1+2.5+3.7+3.7+3.7+3.7
?-8 ????? ?? 0*+1.5+4+5+5.7+5.7+5.7
?-6 ????? ?? 0*+1.7+5+6.5+7.7+7.7+7.7
?-D ????? ?? 0*+1+3.7+5.5+7.7+9.5+10.7
?-0 ????? ?? 0*+2.7+5.7+9+13.7+17.2+19.7

* = See procedure for setting 1 KHz below

If your equalizer has more bands than those shown, or has different frequencies, then linearly interpolate the missing dB values.

Use the following procedure to set the 1 KHz slider:

  1. Start with all sliders in the 0 dB setting.
  2. Set all of the other sliders first, including any interpolated ones.
  3. Imagine a line connecting the nearest sliders, one on each side of 1 KHz.
  4. Move the 1 KHz slider to that line, so it is exactly between the sliders nearest to it.
  5. Now move the 1 KHz slider about a third of the way back toward 0 dB.
  6. This is the correct setting.

Equalizing Old Records