Hi Tony,

Here are some of the best free tools for the mixing job you need.

1. mp3DirectCut (Windows)

Supported Formats: AAC, MP3.
mp3DirectCut is a nifty little audio editor that’s lightweight and barebones: you can’t do much with it, but it’s very good at what it can do. Basic operations include cutting, copying, pasting, and recording audio.

What sets this app apart from most is the fact that it directly manipulates audio files without having to decompress them first. Not only does this result in a faster workflow, but it also preserves the original audio quality because it doesn’t need to be re-compressed.

Download link: mp3DirectCut

2. Mp3Splt (Windows, Mac, Linux)

Supported Formats: FLAC, MP3, OGG.
First things first, make sure you download Mp3Splt-GTK rather than simply Mp3Splt (which is a command line tool that’s more bother to learn than simply using the GTK version’s graphical interface).
Like mp3DirectCut, Mp3Splt can work on an audio file without having to decompress it first, resulting in a fast workflow and no impact to audio quality. This app is much simple though: you just pick a start and end time, then export that selection as a separate audio file.

Download link Mp3Splt

3. MP3 Toolkit (Windows)

Supported Formats: AAC, FLAC, MP3, OGG, WAV, WMA, and more.
MP3 Toolkit is a collection of six separate audio manipulation tools that are all useful in some way: Converter, Ripper, Tag Editor, Merger, Cutter, and Recorder. For this article, we’re most interested in the Merger and Cutter.
You can download MP3 Toolkit for free, which will be marked as Unregistered. There’s no indication of whether this version limits features or has a time limit.
Download link: MP3 Toolkit

I hope this helps.

Regards,
Lokesh