After installation of these two files (replacing pre-installed Sound 7.1), monaural sounds came from the right channel ONLY through headphones and the Macintosh TV computer's internal stereo speakers, whereas with Sound 7.1 mono sounds were in both left and right channels. Audio CDs and stereo TV broadcasts remain functional.
There are two workarounds to this issue:
1. Removed Sound 8.0.1 and Sound Manager 3.0 and revert to Sound 7.1.
2. Install System 7.5. The new Sound Manager extension functionality has been built into the System.