Harrer was the co-principle player of the bass section in the Radio Symphony Orchestra Vienna from 1978 to 1996 and from 1979 to 1982 he was the solo bass player for the Viennese Chamber Opera. He has been a regular guest player for the Vienna Chamber Orchestra, the Vienna State Opera and the Vienna Philharmonics since 1996.
After completing his Art Diploma in 1979 Ludwig Streicher invited him to be his assistant in the University of Music in Vienna. Since 1996 he is a double bass professor in the Saarbruecken Academy of Music. He has held several courses and masterclasses in Europe, Asia and the USA.
He is very much sought after as a chamber musician and played with many ensembles, covering all styles from renaissance music using original instruments to the most modern avant garde music.
As a soloist he has played throughout Austria, Germany, Italy, Poland, Hungary, Cyprus, Spain, Portugal, the Philippines, Taiwan, China, Argentina, Chile, Colombia and Panama. He has recorded several CDs and has played for many radio and television stations.
1. J.S.Bach - Arioso
2. R. Schumann - Fantasiestuecke op. 73, 1. mov
3. R. Schumann - Fantasiestuecke op. 73, 2. mov
4. R. Schumann - Fantasiestuecke op. 73, 3. mov
5. G. Frescobaldi - Canzone nr. 6
6. G. Rossini - Une Larme pour Basse
7. J.M.Sperger - Sonate E-Dur, 1. mov
8. J.M.Sperger - Sonate E-Dur, 2. mov
9. J.M.Sperger - Sonate E-Dur, 3. mov
10. K. Guettler - Greensleeves
11. J.S.Bach - Sonate BWV 1028, 1. mov
12. J.S.Bach - Sonate BWV 1028, 2. mov
13. J.S.Bach - Sonate BWV 1028, 3. mov
14. J.S.Bach - Sonate BWV 1028, 4. mov
15. B.d.Laserna - Tonatilla