Is there any possibility to convert .xlsx spreadsheets to .mp3 format?
This is certainly an unusual and uncommon request, still, converting Microsoft Excel Spreadsheets directly to MP3 Audio Files (.xlsx to .mp3 conversion) might be possible. This typically relates to users attempting to transcribe audio data stored in XLSX spreadsheets to MP3 audio format.
A couple of dedicated programs claim to be able to convert XLSX to MP3. Try using, for example, the Excel to MP3 Converter developed by Sobolsoft.
A free MS Excel spreadsheets to MP3 audio format conversion tool for Windows.