Significance The wide dynamic range of sound encoding enables perception of sounds varying over six orders of magnitude, thought to be collectively achieved by distinct classes of type I spiral ganglion neurons (SGNs) contacting each inner hair cell (IHC). These synaptic contacts have been shown to vary according to the SGN firing properties along the modiolar–pillar axis. It has also been shown that the IHCs spatially segregate active zones (AZs) with different Ca ²⁺ -influx properties, proposing an attractive candidate mechanism for the diverse sound encoding properties among SGNs. Our study, combining confocal/STED immunofluorescence microscopy, patch-clamp, and Ca ²⁺ imaging, proposes that Gαi and LGN, involved in planar polarity mechanisms at the IHC apex, contribute to establish the spatial gradient of IHC AZ properties.