Volume2 - Volume2 is an advanced Windows audio mixer, a complete replacement for the standard Volume Control.
Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.
Sound Control - App-specific volume control
GarageBand - GarageBand is a fully equipped music creation studio for Mac
Power mixer - Power Mixer is a complete Windows volume control replacement.
Adobe Audition - Mix, edit, and create audio content in Adobe Audition CC with a comprehensive toolset that includes multitrack, waveform, and spectral display.