Voicings

C7

Drop 2 dominant 7, root in bass

Drop 2Drop 2
C3 G3 Bb3 E4Loading piano…
  1. C3R
  2. G35
  3. Bb3b7
  4. E43

Guide tones carry the chord's sound: the 3rd (4th on sus chords) and the 7th (or 6th).

Source: Common practice