FMOD Ex is described as 'FMOD is a proprietary audio library that plays music files of diverse formats on many different operating system platforms, used in games and software applications to provide audio functionality' and is an app in the Development category. There are six alternatives to FMOD Ex for a variety of platforms, including Mac, Windows, Linux, Android and iPhone. The best alternative is Wwise, which is free. Other great apps like FMOD Ex are PortAudio (Free, Open Source), RtAudio (Free, Open Source), OpenAL Soft (Free, Open Source) and SoLoud (Free, Open Source).
RtAudio is a set of C++ classes that provide a common API for realtime audio input/output across Linux, Macintosh OS-X and Windows operating systems. RtAudio significantly simplifies the process of interacting with computer audio hardware.
OpenAL Soft is an LGPL-licensed, cross-platform, software implementation of the OpenAL 3D audio API. It's forked from the open-sourced Windows version available originally from the SVN repository at openal.org.