ffmpeg bash script: wav extraction from videos

After hunting for hours through forums, I'm stuck from just achieving basics with ffmpeg with my limited bash knowledge.

What I'm trying to achieve:

6TB of video files of different codecs on my headless server (of mainly wrappers .mov & mp4) in several directories. I would like to extract the audio from them as .wav, and save the audio in a separate location KEEPING the folder structures in this new location. (I don't mind if re-encoding audio but if just extracting the right audio codec is faster, and less processing, then better!)

#!/bin/bash
for filename in *.mp4; 
do
    stub="${filename%.*}" 
   /usr/local/bin/ffmpeg -i "${stub}.mp4" -vn -acodec copy "Someotherpath/FolderStructureRecreated/${stub}.wav"

sleep 0.1

done