Pictures and description look cool. On my system (Ubuntu 24.04) it looks like I am running into compatibility issues with the java sound system.
javax.sound.sampled.LineUnavailableException: line with format PCM_SIGNED 44100.0 Hz, 16 bit, mono, 2 bytes/frame, little-endian not supported.
at java.desktop/com.sun.media.sound.DirectAudioDevice$DirectDL.implOpen(DirectAudioDevice.java:484)
at java.desktop/com.sun.media.sound.DirectAudioDevice$DirectClip.implOpen(DirectAudioDevice.java:1238)
at java.desktop/com.sun.media.sound.AbstractDataLine.open(AbstractDataLine.java:115)
at java.desktop/com.sun.media.sound.DirectAudioDevice$DirectClip.open(DirectAudioDevice.java:1038)
at java.desktop/com.sun.media.sound.DirectAudioDevice$DirectClip.open(DirectAudioDevice.java:1131)
at tech.mdhughes.gui-audio-player.resetInputStream(guiframe.scm:719)
at tech.mdhughes.gui-audio-player.<init>(guiframe.scm:676)
at understone.startMain(understone.scm:1168)
at understone.run(understone.scm:240)
at gnu.expr.ModuleBody.runAsMain(ModuleBody.java:149)
at understone.main(understone.scm)