The files appear to be used in game and they are playable music, did you call them up as new entries in the music ini file?

Here's a tutorial I used and found really useful

CK256

Custom Music

Author:BBalaz's

Adding custom music to freelancer. In the tutorial, we'll add a custom 'space' music, the one which plays when you are freely exploring space, and there are no hostiles to be seen anywhere.

Freelancer stores the music in a 22kHz MP3 format. Note that the extension is .wav - however, the music is not in "wav format". To be correct, there is no such thing as a wav format. Wav is merely a container. Generally, what you would call a "wav format" is actually called PCM. The music files of Freelancer are MP3 files, in a wav container, using a 22kHz sampling rate, and the Fraunhofer codec. Yes, you will notice, that if you use some other mp3 codec (like LAME, which is the default of, for example, Audacity), FL will not play the music correctly. Also, I've been fiddling around with different versions of the Fraunhofer codec, and they don't seem to work correctly, either. Adding music to Freelancer, however, is not that complicated.

Let's get down to a simple-to-understand, step-by-step tutorial.
1: Create your music file. It is generally a good idea to keep 'space' type music to about two minutes long, 'bar' type music to about one minute in length, and so on.
2: Save it as WAV (PCM). When you are satisfied with your file, export it (or save it) as wav. Sampling rate, so far, doesn't matter, you can keep it as high as you wish.
3: Check the volume of the music. It is a good idea to go to FL's music folder, and open a music file, say, music_li_space, or music_bar_li02. Then, open up your own WAV file and check if it is loud enough. If it isn't loud enough, you'll need to amplify it. Check the appendix at the end of the tutorial. If your music file is loud enough,
4: Open it in WINDOWS SOUND RECORDER. Yes, that simple, seemingly good-for-nothing application. Once your file is open, go to File ==> Properties, then click the "Conversion..." button.
5: Convert your file. Select MPEG Layer-3 as a format, Attributes should be 56 kbit/sec, 24 000 KHz, Stereo. That should work. Click OK and wait for the application to finish converting the file.
6: Save the file! It is generally a good idea to use 'Save as..' in case you might want to get back to the original PCM wav file. You will also notice, that the extension to your MP3 will now be WAV.

At this point, we are done with the file itself. Let's get it working. In the tutorial, let's say our file will be saved as... tutorial_space.mp3 (Creative, isn't it?)

1: Copy the file (tutorial_space.mp3) into Freelancer\Data\Audio\Music.
2: Make sure the file Freelancer\Data\Audio\Music.ini is not write-protected.
3: Open the file "Music.ini" in a text editor. Note that I assume you are using the SDK. If you aren't, you will need binitools, or some other bini decoder/encoder application, but I won't get into that now.
3: You will see blocks of 'Sound' entries. Do a search for music_li_space.
4: Copy and paste music_li_space's block to the end of the file.
5: Now, change the entries:
nickname = music_tutorial_space (<== the nickname you will refer to in the system file)
type = music
file = audio\music\tutorial_space.wav (<== the name of your file!)
attenuation = -6 (<== this is meant to be some sort of volume adjustment, but I found little to no effect when modifying the value.. Play around with it)
streamer = true (<== makes your music fade in and fade out)

6: Save music.ini
7: Open up a system file. We will be using the New York system. Go to Freelancer\Data\Universe\Systems\Li01 and open up Li01.ini
8: Replace the music theme. Scroll down to the 'Music' entry (or do a search for it) and replace
space = music_li_space
with
space = music_tutorial_space (<== NOTE: This is the NICKNAME you defined. Not the filename.)
9: Save the file. That should do it.


APPENDIX:
1. It is ALWAYS better to make backups of all files you modify, and don't EVER work in the game folder, with game files; ALWAYS use copies. This is a general rule of the thumb, and you should stick to it.
2. Windows Sound Recorder can be found in Start menu, All Applications, Accessories, (Entertainment? sorry, my Windows is not English).
3. If you use binitools, remember to 'bini' the files back (encode them) after you 'unbini'-ed them.
4: Increasing/Decreasing music volume. Sound Recorder is capable of doing that under "Effects" - but I'll also give you another example. I use Audacity, a simple audio editor for my files. When your file is open in Audacity, press Ctrl+A (Select All), go to Effect menu ==> Amplify. Set Amplification to a positive or negative value. That will increase or decrease the volume. Note: You might need to "Allow Clipping" to be able to increase the volume - this, however, will have an impact on audio quality in the louder parts of the file.

What I mean is, that Freelancer is not like Half Life or like Jedi Knight or so. It is not enough to name some files some special name and throw them into the game folders to make them part of the game. You have to actually edit ini files and this is precisely what the tutorial says. Its really not that hard, and believe me, music and sounds is perhaps one of the simplest modifications one could do. Without "coding" (though it is more configuring, not programming) one doesn't get anywhere about this game however.

My favourite adoxa, you allways save my life

Yeah, I didn't check that the nicknames and the filenames aren't the same in music.ini in this case.
Thanks!

@Gist:

Thanks for the inputs.

@Gist:

Never mind, it was a great amount of information you shared.
I never played with musics before and frankly I didn't pay attention to the nicknames and filenames in music.ini. It was caffeine related problem I guess.
If I want to make new music in the future your information will be useful.

So, thanks again