Monophonic -- that song was "Forward You Witnesses". Here is the post (by the JW researcher DocBob) about it earlier in this thread:
"Firm and determined, in this time of the end...."This is also my most hated song. Besides being just a bad song, it seems that the author, Erich Frost, was not the steadfast witnesses that both he and the WT make him out to be. According to Gestapo documents, after he was betrayed by August Fehst, Frost ratted out seven other district servants. See http://www.bible.ca/jw-collaboration.htm
This is the song credited to a German JW in a concentration camp, entitled in English, "Forward You Witnesses". In fact, it is referenced in the Holocaust museum in Washington DC.