Play Audio file in writable folder

I tried as follows, but to no avail.

moved files from writable to public/assets/audios

PHP Code:

<audio controls>
      <source src="<?= base_url('assets/audios/'.$line["audiofile"]) ?>" type="audio/mpeg">
      Your browser does not support the audio element.
</audio> 


base_url('assets/audios/'.$line["audiofile"]) print:
http://cdr.local/assets/audios/2021/08/1...07m29s.WAV

directly accessing the url in browser