Rax 

Rax is a powerful application that includes a complex mixer and allows users to make modifications with the sounds produced by their instruments. It comes with a well-polished interface, that automatically changes its size every time components are added or removed. It also incorporates the record function, for saving your projects, and a virtual piano keyboard. Basically, the main interface is a giant mixer, in which the users can choose the features and tools to be displayed. Source, Fader, Pre-Fader, Post-Fader and output can be displayed in the main interface. Users are allowed to make modifications for each component individually, and can also choose the number of components to be displayed. Besides the mixer components, the application also provides a master selection tool, which provides settings that influence all of the individual parts. Basically, you can connect multiple instruments to the Mac, as the tool provides midi support and one mixer for each one.

All taken into consideration, you should give Rax a try; it comes with an appealing interface and an easy-to-use menu and is a professional tool for editing sounds produced by the instruments connected to your Mac.