Since f7 and f8 lower and raise the sound volume, can there be a shortcut key like control+shift+f7 and control+shift+f8 to lower and raise the music stream volume?

To lower the music stream volume press f5 and press f6 to raise it.

that with the shifts, isn't it to long?

i agree with you taylor

The feature request is invalid and due to lack of awareness of the already present keystroke to achieve the same. As mentioned by teardrop in Comment 2, you can press f5 and f6 to reduce and increase the volume of the audio stream respectively.