End Correction
An acoustic correction applied to resonance pipe lengths to account for displacement antinodes forming slightly outside the open pipe ends.
Governing formula
e ≈ 0.6 r, L_effective = L + 0.6 r (One Open End)
SI unit
m
In depth
Air particles just outside the pipe open end move together with air inside the pipe, shifting the true acoustic antinode outward by $sim 0.6$ times pipe radius $r$.
Examples in the real world
Calculating exact resonant organ pipe lengths for precise musical tuning.