I want to add a custom mp3 to my map. I made it in audacity using other portal 2 sound files, so it's a Mono mp3 with 44.1 kHz sample rate (it's name wdc.mp3).

1. I placed it in portal 2\portal2\sound\vo\wheatley\wdc.mp3 (I created the directory vo\wheatley inside portal 2\portal2\sound).

2. Next, in hammer, I created an ambient generic of volume 10, start volume 10, checked the flags "does NOT loop" and "Play everywhere", and unchecked the flag "Start silent" (because I want it to play immediately as the map starts). I selected the "Raw" sound type, refreshed the sound list, and selected vo\wheatley\wdc.mp3 from the dialog box. Then I did a fast compile and started the map.

3. Then I entered "snd_updateaudiocache" in the console and it successfully added vo\wheatley\wdc.mp3 to the sound cache, but the audio still didn't play.

4. Finally I used pakrat to pack wdc.mp3 into the bsp (with the directory of it set as sound\vo\wheatley\wdc.mp3). Even then the new bsp made by pakrat does not play the sound!

I'm out of options, any suggestions?

EDIT: It doesn't work without an input, once I connected a trigger to the ambient generic and checked "Start silent", it played the sound just fine

Maybe give the actual mp3 file?