EQ - A Typical Example

The following example uses all of the techniques discussed. instrumentation is Drums, Bass, Electric Guitar, Keyboard with Lead and Background Vocals. "+" indicates boost and "-" indicates reduction at given frequency.

Kick
-6 @ 400 Hz
+4 @ 5 kHz Reduces box quality. Increases attack

Snare
+4 @7 kHz
+2 @ 100 kHz Increases snap. Adds fullness to high-tuned snare

All Drums
-4 @ 400 Hz
+4 @ 15 kHz Decreases ambiance & increases bass clarity. Increases cymbal sizzle.

Bass
-2 @ 50 Hz
+4 @ 400 Hz
+2 @ 1.5 kHz Increase clarity of bass Adds clarity to bass line and recognition at low volume. Increases pluck and recognition.

Guitar
-4 @ 100 Hz
+2 @ 3 kHz Increases guitar vs. bass distinction. Increases attack ( 3 kHz needs much less boost once 100 Hz is reduced).

keyboards
+4 @ 5 kHz Increases clarity & brightness.

Lead Vocal
+4 @ 10 kHz
+2 @ 5 kHz
At 200 Hz, reduce 2 or 4 to add clarity to low vocals increase 2 or 4 to fill out high vocals.

Bkg. Vocal
-6 @ 5 kHz Sets background back and increases lead vs. background distinction

This "textbook" EQ can’t be expected to work on all sessions. On the right session, however, it would give a very natural sounding recording or mix with surprising clarity and punch.
Note that boosting two instruments at the same frequency was avoided.
Note that reductions were generally larger than boosts.