Luckily, I've found a freeware that let me edit audio tracks and save them as MP3 and some other formats, it's called Audacity. So go get a copy for yourself and try it, I believe it's all you need to do some simple audio editing tasks.
Once you download and install the Audacity, launch it and you'll see something similar to this:
Then follow the steps below
Open the audio file (Wav or MP3) (File > Open). The file shows up as follow, note that this sample file has two audio channels (stereo), so you'd see two rows of wave signal.
- You can play the file from the beginning by selecting the Play button, or you can select a starting point by clicking the mouse on the wave signal then click Play. While the audio is playing, the cursor moves indicating the position of the wave signals being read.
- To cut an unwanted portion of the audio, simply play the file and identify the start and end points of the wave signal you want to cut. Then click and drag the mouse to highlight this portion and click on the scissors button to cut.
- To add a fade-in at the beginning of the file, click and drag the mouse to select a portion at the beginning of the audio wave. Then select Effect from the top menu and selectFade in.
- Similar to fade-out, select a portion of the wave at the end and select Fade Out from the menu.
- To adjust the volume of the entire audio file: Edit > Select > All, then Effect > Amplify. Then adjust the volume with the slider and click OK, don't forget to check the boxAllow Clipping
- You can also adjust the volume for just a portion of the audio file by select and drag the mouse to highlight the portion then use the Amplify menu.
- Once you're done editing, save the file as Wav or MP3: File > Export As WAV or Export As MP