Using most browsers, you should see a 200x58-pixel area below, where your plug-in MIDI player would normally display a control panel. ( Sized for Crescendo, under Netscape. )
If your browser can interpret the <EMBED> tag properly, the short "DS9.MID" file should download and play in the background.
You can explicitly download DS9.MID here.
Those Arachne users without the "cndmidi" APM should, however, be able to hear a short Embedded WAV file, a single blast on a railroad warning horn. If your browser has both midi and wav capability, you should hear BOTH, AT THE SAME TIME.
If not, you can download BLAST.WAV here.
The PLANY.EXE program included with Arachne also permits play of older "AU" sound files. As before, the short file will play at the same time as a background midi. If your browser is fully functional for sounds, you should hear all three.
If not, you can download BEEPBEEP.AU here.
Note: Arachne doesn't support the MSIE-style "BGSOUND" form of embedding sound files in HTML. It probably won't in the future, either. Have you considered upgrading to an efficient browser and/or non-windows operating system ?