The KMix package contains a KDE Frameworks-based Sound Mixer that integrates nicely with Plasma.
This package is known to build and work properly using an LFS 13.1 platform.
Download (HTTP): https://download.kde.org/stable/release-service/26.04.3/src/kmix-26.04.3.tar.xz
Download MD5 sum: 926f4efced16041ff3da03bbd008b676
Download size: 1.1 MB
Estimated disk space required: 25 MB
Estimated build time: 0.2 SBU (using parallelism=4)
Install KMix by running the following commands:
mkdir build &&
cd build &&
cmake -D CMAKE_INSTALL_PREFIX=$KF6_PREFIX \
-D CMAKE_BUILD_TYPE=Release \
-D BUILD_TESTING=OFF \
-W no-author .. &&
make
This package does not come with a test suite.
Now, as the root user:
make install