Diophonic is a production music duo which consists of Axel Broszeit (also known as Axel Coon, ex-member of Scooter) and Ralf Goebel (sometimes spellt Ralf Göbel). Up to date, they have in store 28 albums (in order of release):

• Big Rock Anthems (2016),
• Resonance (2016),
• Defeated (2016),
• Electro Synthrock (2016),
• The Chill Side of Pop (2016),
• Permanent Vacation (2017),
• Trap King (2017),
• Punch (2017),
• Future Bass (2017),
• Kelevra (2017),
• Future Bass - Pop (2017),
• Future Bass - Drop (2017),
• Oriental Adventures (2017),
• Wonderous (2017),
• Ballin (2017),
• Angel of Death (2017),
• Earthquake (2018),
• 80’s Journey (2018),
• Sadness (2018),
• Tropical Dance (2019),
• Shaftly Suspicious (2019),
• Anvil (2019),
• Biosphere (2019)
• Gucci Cowboy (2019),
• Unbreakable Bonds (2019),
• Branding (2019),
• Trap King (Volume 2) (2020),
• Unsolved Cases (2020).

They also keep releasing albums together under their real names. Most correct pages on Last.fm:

Axel Broszeit, Ralf Göbel ,
Axel Coon, Ralf Göbel,
Ralf Göbel, Axel Coon.

The links don’t include other variations, like “&” or “/”, because there’s no common preference in such releases.
Usage of “ö” over “oe” is chosen as the standard for German spelling, with regard to its appearance on early releases by the artist. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.