The Background Noise Measure is an optional step of the Wizard you can use to optimize how your recordings are auto-splitting. To configure the background noise, from the Split Recordings page of the Wizard, click the Current Noise Floor button in the Splitting Parameters section.
To start off, find the silent portion between the end of a song and the start of the next song.
Next, click the Measure Noise Floor button, and let the software do its work. Once it is done, the noise floor volume will appear below the volume display. You do not need to do anything further here, the software will store that value and use it later on.
If you are not happy with the automatic noise floor detector, you are free to enter what you think the level of the noise floor should be. Check the box Manually specify noise floor, and then enter a value. A low noise floor means the splitting feature will be less tolerant of background noise than a high noise floor. Therefore, if your recording contains a good deal of noise due to the age or condition of the vinyl or tape during "silent" portions between recordings, you should try a higher dB level for the noise floor.
Note: The noise floor measurement must be done for every album from which you are recording. If you do it once and then apply the measured value across all albums, the auto-splitter tool may not find the ends of tracks with optimal accuracy.