Apps similar to FMOD Ex include OpenAL Soft, which is free and open source. Other options are PortAudio, Wwise, RtAudio and AudioKit. In total there are seven Software Frameworks like FMOD Ex for Mac, Windows, Linux, the web and Android.
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 openal.org's SVN repository (now defunct).
PortAudio is a cross platform, open-source, audio I/O library. It provides a very simple API for recording and/or playing sound using a simple callback function.
"Wwise® is the most advanced, feature-rich interactive sound engine for games, bar none. Whether you're an indie or a multi-million dollar production, Wwise will work for you." - Audiokinetic.com
Canada
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.
AudioKit is the leading open-source audio framework. It powers millions of app installs. AudioKit allows developers to quickly add professional audio functionality to iOS, macOS, and Apple Watch apps.
United States
Anti Tapes Studio is a dependency-free Web Audio engine for designing responsive sound for software, web, and mobile interfaces.
United States
SoLoud is portable - the c/c++ code base is written in portable way, and the code has been used on various platforms including windows, osx, linux, as well as android and even ps4. (I'm not responsible for many of the platforms, though, and for licensing reasons, ps4 code is...
Finland
EU
