Herzfrequenz is an album by Blümchen that released in 1996 on the label control. This album is a mix of euro house and happy hardcore.
This album is awesome~! It mixes elements from the genres very well which creates an awesome listening experience. Lots of euro house singing and fun silly melodies, then combined with hardcore kicks/percussion and happy hardcore melodies and rhythms. The songs range between the presence of the two genres, sometime its more euro house, sometimes its more happy hardcore, but its often mixed.
I really like this album, listen to some tracks here.