Field measurements of multiple offshore bar spacing were compared to theory and wave measurements to corroborate the suggestion that bar formation and spacing are controlled by standing waves in the infragravity range (0.5--5 min). Theoretical and experimental studies predict the reflection of progressive waves from a shoreline as standing waves. Associated drift in the bottom boundary layer is expected to produce sediment accumulation and bar formation under either the nodal or the antinodal points. Measurements of waves in the infragravity spectrum confirm the occurrence of such standing waves, and spacing of offshore bars in adjacent areas correlates well with the predicted position of the bars.