CS:GO Join Sound is a simple plugin with a welcome sound.
I found it in an old folder, so I adjusted a bit to cs:go.
Place joinsound.smx in Addons > Sourcemod > Plugins
You can place the sound map in the root directory CS:GO > Place here
Use
sm_start_sound "music/map/sound.
mp3"
Remember, CS:GO not support WAV or something
Use only .mp3 Place your mp3 in Sound/music/yourfileormap
Use Audacity to convert your music to mp3 format if you dont know other options.
A little plugin, but it works
Thanks!