Boom is a simple volume booster application that lets you boost the volume of your Mac, your music, and video files. Changing the volume with Boom is the same as changing the volume normally. It can boost the volume of videos on YouTube or Hulu, your music playing on iTunes, voice applications like Skype and iChat, and your favorite Games.
Boilsoft Audio Recorder for Mac records sound from microphones, CD players, line-in devices, and other applications (like Skype, QuickTime Player, RealPlayer, iTunes, VLC, or DVD Player) into popular audio formats, including MP3, WAV, AIFF, AAC, AC3, AU, FLAC, M4A, M4R, MATROSK, and OGG. It can also edit audio file or recordings, and supports recording audio in batch.