How to make the Radio play custom music

How to make the Aperture Science Radio play your own custom songs with Audacity and Goldwave!

Introduction

Hey, so this is my first guide on Steam.

Basically I wanted to put my own custom music inside Portal, for the radio to play. After running around on the internet for hours, jumping around between the valve wiki and the steam forums, i finally learned how to do it, so i tought of sharing it here, because there wasnt a specific tutorial anywhere

First of all, i will be covering every necessary detail in a specific but simple way, so even begginers who have never touched any of these programs can make their own custom content. I will also add some optional steps, but wont be explaining as much because those are aimed at more advanced users, so only the important stuff will be mentioned.

So now, the programs we will be using:

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

Technically, you can use other programs, but these are free, begginer-friendly and will help you get the job done easily.

Preparing the audio

First of all, we will be needing, obviously, a music file to replace the radio jingle. You can technically use any song you want (and if you want, you can use voices, sound effects, anything!). The file type doesnt really matter cause we will be converting everything inside Audacity. One thing you'll probably want is a good quality audio, but again, anything works!

I will be using a small section of "The One True Path" by Kero Kero Bonito, which i cut to make a perfect loop, but you can use a full song (even tho, i suggest you find a way to make the song loop. One thing i usually do is cut the "decay" at the end of the song and then place it at the start, or just cut it exactly where it ends and starts, but i prefer to use small loops instead of entire songs)

Editing in Audacity

Now, we open up Audacity and drag the audio inside of it. It'll look something like this:
Obviously, your wave form will look different because you're probably using another song.

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

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

Next, we need to make the audio a mono file, which means there will be one channel instead of two, playing the same thing on both left and right (sorry Beatles fans, no panning here). To do this, first we select the audio by pressing "Ctrl+A", then we go to "Tracks" on the top menu, select "Mix" and then we click on "Mix stereo down to mono". This will produce 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 (Yes, file name too):

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.

[Optional] Making the audio sound like it comes from a radio

If you compare the original radio sound file from portal and any song, you'll notice there's a very important difference: the radio music actually sounds like it comes from a small radio.

There are various ways to achieve this effect. The most common one would be just EQ'ing the song so there's almost no bass and not a lot of high frequencies. But the method i use is running the song via iVinyl[www.izotope.com], a VST plugin that works with Audacity. Here's the configuration i recommend:


You can also play around a little bit with this to make the "perfect radio effect" in your opinion. Its up to you!

Making the audio loop with GoldWave

So this is an interesting thing: Instead of something like a checkbox or a line of text inside Source/Hammer that tells the engine to loop the audio, this information is stored inside the audio file, via cue points (this is a WAV-only feature, which means mp3 files dont have this option)

To set cue points inside the audio file, we need to open GoldWave and open our sound file by dragging it in. It should look something like this


Now, we need to 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.


Next we do the same thing again, but we name it "end_cue" and set the position to be Finish marker.
We should have something like this (obviously the times will be different cause your audio will have a different lenght):


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

[Optional] Starting the loop elsewhere in the song

So you may not want your loop to start at, well, the start of the song. There is a solution for that!

In GoldWave, instead of setting the start_cue at the start of the song, set the placement as "Beginning of the file" and in the small box next to the "+", add the specific time in the song where you want the loop to start (hours:minutes:seconds:miliseconds). And there you go! The song will play until the end and then repeat from the point you selected.


This works for songs with intros, or if you just want a part of the song to be looped

Creating the "custom" folder

So for this next step, we need to go to our Portal data folder, which is where the game is installed. It's normally in C:\Program Files (x86)\Steam\steamapps\common\Portal, but i suggest to check where it is installed.
When we're there, click on the "portal" subfolder and create another folder called "custom". This is where our custom content will be located. Inside, create another folder and call it whatever you want (I called mine "customs"). Then, keep creating folders until it looks like this


Inside "music" we wil be placing our audio file (which, again, should be called "looping_radio_mix"). And that should be it! We now have our new radio song!

If it doesnt work in-game, make sure that you followed all the steps correcly, and if it still doesnt work or you have any doubts, leave a comment and I'll try to help!

[GeeDino]

MEGALOVANIA

[Muffin Winklegooble III]

for some reason, the custom music works, but it doesn't play from the radio, it plays from an offset away from the radio??

[Brolya Democratic Republic]

Doesn't work Me sad

[Olimon7661]

The Aperture Science 85.2 FM Radio is now playing: UNDERTALE OST 100 MEGALOVANIA

[Auto]

Thank you.

[vigilante42]

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[vigilante42]

what

[chris]

why is everyone getting all angry, it seems legit

[ZeDarkOne]

you used the wrong sample rate

[josephmother]

@younga wdym?