Hello there.

I wanted to put my own music on the Portal Radio. After hours of running around the internet, I finally learned how to do this, so I thought I'd share it here since I was not able to find a tutorial anywhere else.

Software you need:

- Audacity[www.audacityteam.org]
- Goldwave[www.goldwave.com]

You could use other programs, but these are free, beginner-friendly, and get the job done quickly.

First of all, we need a music file to replace the radio jingle. You can use any song you want. The file type doesn't really matter since we'll be editing everything in Audacity. One thing you're looking for is good sound quality, but still, anything goes!

Now we open Audacity and drag the file into it. It will look like this.



Obviously your waveform will look different because you are most likely using a different track.

So now we want to make sure the format and sample rate are exactly how we want them. For this, you must click here


and set the Format to "16-bit PCM" and the Rate to "44100 Hz"

Next we need to convert the audio to a mono file, which means there will be one channel instead of two playing the same left and right. To do this, first select the audio by pressing "Ctrl + A", then go to "Tracks" in the top menu, select "Mix" and then click "Mix Stereo Down to Mono". This will generate a mono file.

Now, our audio is ready to be exported! To do so, we click on "File" on the top menu, and click "Export", and choose "Export as WAV"








We want to check our export settings are correct. It should look something like this, and if not, make sure to set them this way:





So that's it! We now have an audio file that will play inside the game. So the next thing to do is configure it so it loops in-game.

Instead of something like a checkbox or a line of text inside Source that tells the engine to loop the audio, this information is stored inside the audio file, via cue points.


To set cue points, we need to open GoldWave and open our sound file. It should look something like this




Next, go to the cue points menu. To do so, click here.
















Click on "New" on the bottom and set a cue point called "start_cue". This will be the start of our loop.
















Now we do the same thing, but we name it "end_cue" and set the position to be Finish marker.
We should have something like this:















Then we close the window and save our audio file.
And then we're done! A WAV file that Portal can play and loop perfectly!

For the next step, we need to go to the portal data folder where the game is installed. It is usually located in C:\Program Files (x86)\Steam\steamapps\common\Portal, but I suggest you check where it is installed.
When we get there, click on the subfolder "Portal" and create a new folder called "Custom". This is where our custom content will be located. Inside it, create another folder and call it whatever you want. (I call mine "custom") and then keep creating folders until it looks like this.




Under "Music" we put the audio file (which should be named "looping_radio_mix"). And that should be it! We now have our new radio song!

If it doesn't work in the game, make sure you followed all the steps correctly, and if it still doesn't work or you have any questions, leave a comment and I'll try to help!