Equal temperament divides the octave into twelve equal steps, comprimising intonation for convenience. Pure intonation uses simple ratios to derive intervals.

The root note at 128 Hz is paired with either

-- an equal-tempered third: ~161.27 Hz
derived as 128 × 2^(4/12)

play tempered


-- or a pure third: 160 Hz
derived as 128 × 5/4

play pure