Download Audacity is an audio editor online, ie, the user opens a sound file with this software and can see the whole map of sound waves online and make changes, applying effects, cuts, etc. the desired points.
With it you can make edits from the simplest (cuts at the start or end, joining files, removing hiss and several others) to work more professional (compositions, appliance effects of pre-defined or custom editing frequency, change in and more volume).
To edit anything, you first need to import it into the Audacity (to do this drag the file into it and drop menu or click on the File option and I import . done this you will see the map of audio on your screen in this way:
To begin the modifications the user chooses the desired areas (or any extension and to apply the entire file) and applies the effect or other desired action.
Some interesting features
Recording: it can record sound from microphone or other input source sound (with this you can digitize records, K7 tapes and other audio sources), and in 16, 24 or 32-bit;
Several effects: it comes with a number of preset effects and can be set as: noise reduction, expanding the bass, echo, normalizing volume, fade out, change the audio speed and several others;
Editing files easier because you have at your disposal option to reverse all actions made without limit of time, ie, applied a thousand changes, you can revert all of them or how you see fit;
Most used tools around the panel and identifying their functions;
Accepts external plug-ins: it increases the options and tools it. There are packages available on the internet for various specific purposes.
For those unfamiliar sound editing can be a bit tricky to use this program because, despite coming with the Portuguese language in Brazil, many of the terms used are in English and are not with clear explanations.