You can lengthen the delay between sounds by inserting a silence to the end of the sound file itself.
Alternatively, you can remove the sound clips from your Player / NPC Inspector and use the dedicated "Footstep Sounds" component instead, which gives more options for fine-tuning the way they're played.
Comments
Alternatively, you can remove the sound clips from your Player / NPC Inspector and use the dedicated "Footstep Sounds" component instead, which gives more options for fine-tuning the way they're played.