This guide is tagged as advanced since it requires knowledge of how to use command line tools.

SimPE and Audio Files:

SimPE's extract function gives all extracted sound files the .mp3 extension. This is not always correct, as the game uses multiple audio file formats. This causes some of the extracted sound files to not work.

The game has three sound file formats:
- MP3
- Maxis XA
- Speex

MP3 is typically used for the music, while XA is used for sounds and sound effects, and Speex is used for speech.
There is also a couple files that are listed as MP3 files in SimPE, but are actually text/xml files. They have groups 0xADD550A7 and 0x1D6962CF.

Finding The Correct File Format:

Method 1:
1- Open SimPE.
2- Open a package file containing sound files. The game's sound files are labeled "mp3 or XA sound file (MP3)" by SimPE, although as mentioned above, these are not always MP3.
3- Click on one of the sound files
4- Click on Hex in the Plugin View
5- Check the first few characters that appear in the right view.
6- if the first two characters are XA, then the file's format is XA, if the first three characters are SPX, then the file's format is Speex, if the start of the file doesn't contain either of these characters, then the file is either an MP3 file, or is a text/xml file.

Method 2:
1- Open SimPE.
2- Open a package file that contains sound files.
3- Right-click on one of the sound files, then click Extract and save the file.
4- Open the file using a text editor, such as Notepad.
5- Follow the same procedure as step 6 from method 1 to recognize the format of the file.

Making The Audio Files Playable:

1 - MP3:
With MP3, it's just a matter of extracting the file using SimPE. The file should then be immediately playable.

2- XA:
Extract the file using SimPE, then convert the XA file to another file format using FFmpeg:

3 - Speex:
Extract the file using SimPE, then use my Python script to convert the speex file to to a wav file: