MP3 bit-rate 32 not 16

I have Wavelab 12 Elements on PC - Win11 Pro - 16Gb Ram - 12th gen i7 - REM Babyface sound card.
I can’t work out how to export (Save As) MP3’s at 16bit. It’s always 32bit float.
That doesn’t play on some older players (my clients can be old-fashioned).
If I open a 32bit float MP3 file, I can’t find any way to change it to 16bit.
How do I set MP3 exports to 16bit as default, please?

MP3s are neither 16 nor 32 bit.
The decoder, on the other hand, can choose to decode the MP3 into 16 or 32 bit PCM. This is independent from the MP3 file. This will be the same, whatever the MP3 file.

WaveLab decodes in 32 bit float, but you can choose to re-render to 16 bit. But I don’t see what would be the interest of this.

What you mean by 16 and 32 bits is not the bit rate, but the bit depth. MP3 files don’t have a bit depth, only a bit rate. It is a measure for the amount of information per unit of time (kBit/s) and thus indirectly for the quality of the compressed audio signal.
Wave (WAV) files, on the other hand, have a specific bit depth, e.g. 16, 24 or 32 bits. You can try to convert wave files with different bit depths into MP3 files and you will get completely identical MP3 files, because the bit depth of the source file is irrelevant for MP3.

What you’ll want do is render, rather than save or export.

After loading an MP3 (which WaveLab decodes internally) you’ll see something like this in the bottom right:

Assuming you’ve opened an MP3 file and want to obtain 16-bit WAV files, once you see the waveform you select the Render tab and choose file name, location and as format, choose “Wav 16-bit”.
(and that’s bit depth you were referring to, not bit rate)

Those are all good an informative answers and I’m sorry for not being specific.
However, the problem remains. 32bit float MP3 files do not play on older Media Player versions, whereas 16bit MP3’s do.
How do I create 16bit MP3 files, please?

Render is the answer, check answer above…

regards S-EH

I’ll go back to school.
Thank you all.

As said, this is not possible because MP3 files don’t have bit depth at all.