Resampling with ffmpeg: Since I am using ffmpeg, I think they only allow -ar resampling at 48000,44100,32000, 22050, 16000, 11025. If I put in 24000, I recall it rounding to 22050. There is supposed to be -af "aformat=sample_fmts=s16:sample_rates=%Resampling%" doesn't seem to work, since the console is saying a regular sample rate, and the playback of the Exhale file is 44.1 or 48 kHz (I don't recall which.).
ffmpeg has no problem to resample to 24Khz. In fact you can input whatever value: 24000, 12345, 501, etc. Now, container/codec supporting these unusual rates is another problem (wav is Ok).
If you like to have
placebo extra quality, add
-af aresample=resampler=soxr:precision=28after your -ar %Resampling% parameter.
FFmpeg Resampler Documentation
I am still getting interleaving complaints or rounding when I try a non typical sample rate. But I am piping the wav to Exhale. It might be that Exhale only accepts certain sample rates.
I added your placebo sox resample af filter, just in case it helps. At least, I don't see any console complaints, so I think it must be working splendidly. I may even get around to googling what it does, someday.