LPB
LPB stands for Lines Per Beat, and is used to specify how many tracker lines to play in one beat.In trackers, this value is often important since it sets the edit-resolution. But in Radium, it's more convenient to change the LZ value instead.
LPB would in most situations be set to 4, and not changed afterwards.
Default LPB
The LPB text entry lets you set the default LPB. The LPB text entry is either placed in the upper left corner of the editor, or in the bottom bar:

LPB track
The LPB track lets you override the default LPB for a block.To enable the LPB track, right-click somewhere in the timing area of the editor (to the left of the note tracks), and enable "LPB".
LPB format: xx, where xx goes between 1 and 99. Notes: * If xx has an 'm' prefix, it means that the line contains more than one LPB entry. The last LPB is displayed. * If xx has a 'd' prefix, it means that the LPB entry starts below the start of the line.
Tips:
- To remove an LPB entry, press DEL.