How can I compress an audio file to under 16MB on Windows?

So let me break down using FLAC Frontend to compress audio file to 16 MB on Windows 10 in plain terms. 

FLAC Frontend is essentially a command-line wrapper for the FLAC FLAC encoder. If you are not accustomed to entering commands in the terminal, then it is your ideal choice. You simply need to drag and drop the WAV file into the window, select the compression level from 0 (fastest, with the least compression) to 8, and then click "Encode" to complete the operation. It is also portable and does not require installation.

The compression level will affect the final result you achieve. Level 5 is the default setting and can provide a good compression effect. However, if you really need to compress audio file to 16 MB and you have reached the limit, then increase the level to 8. This will allow you to compress all the bytes as much as possible. It should be noted that the processing time for level 8 will be significantly longer, but the difference in file size between level 5 and level 8 is usually very small, possibly only a few percentage points.

There is a notable exception: sometimes FLAC can compress certain audio files far beyond the normal range, for instance, to 20% of the original size. This situation usually occurs in audio files that contain a lot of silence, have identical stereo channels, or were sampled from a lower bit depth. Therefore, if your source file has these characteristics, you might end up with an unexpectedly small FLAC file.