Sound playback is supported through AHI-Handler/AUDIO:.

Get the OS4 native AHI-Handler from here:
os4depot.net/index.php?function=showfile&file=driver/handler/ahi-handler.lzx

http://logarithmic.net/pfh/bonk

Bonk is a an audio compression program that operates in both lossy and lossless
modes. The compression method Bonk uses is quite simple compared to other lossy
formats (such as MP3), and is based on speech compression techniques. It is
nevertheless capable of producing a high compression ratio while maintaining
good sound quality.

In lossy mode, it averages 14:1 compression while remaining almost perceptually
lossless. This corresponds to 95 kbps for reasonable quality audio.

In lossless mode the original audio file can be recovered exactly. Lossless
mode typically achieves around 2:1 compression.

Bonk compiles under Linux, FreeBSD, NetBSD and OpenBSD. (Note: I personally
only have access to Linux machines. I can't test Bonk on other operating
systems, just apply patches people send me. So if it isn't working on other
systems, please email me!)

[ Bonk lossy/lossless audio compressor (version 0.6) ]

Copyright (C) 2001 Paul Harrison
This is free software distributed under the GNU General Public License.
See the source for further information.

[ Encoding into BONK format ]

  bonk encode [options] file1.wav file2.wav ...

  Options:
    -q n.nn      Set sample quantization level to n.nn
                   (default 1.00)
    -d n         Set downsampling ratio to n:1
                   (default 2, use 1 to disable)
    -s n         Set predictor size to n
                   (default 128, use 10 for speech)
    -m on        Enable middle/side rather than left/right stereo encoding
                   (default)
    -m off       Disable middle/side encoding
    -l           Lossless encoding mode
    -a "Blah"    Specify who the file is by
    -t "Blah"    Specify the title of the file
    -c "Blah"    Include a comment in the file
    -o file.bonk Write output to file.bonk

[ Decoding back to WAV format ]

  bonk decode [options] file1.bonk file2.bonk ...

  Options:
    -o file.wav  Write output to file.wav

[ Playing BONK format files ]

  bonk play [options] file1.bonk file2.bonk ...

  Options:
    -r           Random order
    -l           Loop