I have ffplay~ installed but is there a way to write any normal soundfile to an array? (I thought ffplay~ would just make it work, but no...).
[soundfiler] with mp3
The most expedient solution is to convert your mp3s to wav on disk using an external tool.
If there is a Pd external to run shell commands, maybe Pd could run the converter process for you (e.g.
ffmpeg). If not, you'd have to do it by hand outside of Pd.
You can also use [snd.file] from ceammc lib that support many various formats.