What is AAX, AU and VST plugins? AAX, AU (AudioUnit) and VST plugins are software modules that can be loaded inside music production applications such as Cubase, Logic Pro, ProTools, WaveLab, Live, Reaper, Sonar and others. Plugins are usually used to improve, enhance and sculpt the audio recordings, both complete songs and individual tracks such as vocals, drums, synths and guitars, etc. Each plugin belongs to its distinctive category such as equalizers, reverbs and compressors, etc. Our web site offers you a variety of free and paid plugins to meet your needs. Interesting plugins can be downloaded instantly with a press of a download button.