Just finished this task for them.  Uploading the 450 audio files through the app now.

The recording process wasn't too bad,  but it did take a lot of tries to find the perfect position to record in because my phone's a bit old.  I probably did 700 recordings instead of 450 because I failed a lot.  Regardless,  it only took about 2 hours.

Will update this post when I get paid.