Conversation so far:
What led the band to go independent?
After Jerome's departure, founder Edgar Froese steered the band in a direction somewhat reminiscent of material throughout their career.
What happened then?
In later years, Tangerine Dream released albums in series.
Were any of the albums successful?
CANNOTANSWER.

Question: What was the music like during this time?
Self-contained rewrite: What was the music like during the time Tangerine Dreams released albums in series??