Yeah sorry my question was half a question, half suggestion of macOS side feature for the future, with a supported framework from Apple for hardware input middleware apps. Like OS extensions. Would be cool, but my idea will probably not raise to much attention. I will have a closer look though to the Audio Unit framework and others. Thx. There are apps already that create a loopback virtual audio input that you can use. Cool but I wished more like a officially supported framework for intercepting a signal doing some logic on it without loopback since I discovered some apps (video / audio calls such as QQ and WeChat) that do not support selection of the input device within the app. Also applying filters with those loopback solutions is difficult. I came to this because I would like to improve the audio input without complicated loopback stuff for every app that uses the input. Could be the same for video input, output, data buses, wifi, everything. In the end offering Apple and developers new kinds of Apps as macOS extensions (similar to Safari extensions). Thx for the reply.