Alright, I have attached both the .sp file and the .smx . This is a very basic plugin, and I used some source code from R-Hehl's plugin (
https://forums.alliedmods.net/showthread.php?p=552491 ).
It works very simply. When a player dies it checks if that player is in game, and then if the attacker is not a bot. It will then play your sound ( or any sound wanted ) to the attacker. I played around with this a little bit and noticed that the mp3 file you gave me is rather quiet, and you can only really hear it if no one is shooting. If you find another one you want to use, just edit the cvar ( sm_death_sound ). The default directory is death_sound/killnotifysound.mp3 . So on your server go into your sound folder, make a death_sound folder, and add the killnotifysound.mp3 file. The plugin will automatically add the file to the download list, but you will still want to add it to your fast download.
If you think of something else to add, pm or post and I will try it ( I am still rather new at this though ).