[Andy Burns[_2_]]

John Williamson wrote:

I just opened your original .wav file in Adobe Audition, and it was a
compressed file anyway before you started processing it.

Filename:*** x.wav
Folder:*** F:\Downloads\a-mp3 (1)
File Type:*** 48000Hz, 16-bit, Mono
Uncompressed Size:*** 374.71 KB (383,708 bytes)
File Format:*** ACM Waveform
****Microsoft ACM: IMA ADPCM

Maybe it was originally recorded with ATRAC compression, if originated
on Mike's minidisc recorder?