Dr. David-Sinclair Cassel

Founder | Managing Director

About myself

Growing up with 6 brothers & 5 sisters in a multi-cultural family in New Zealand certainly had its challenges & moments. Our parents taught us about the power of reaching out to others with music, performance & entertainment. My fondest memories were travelling around with my family performing on many different stages.

This passion has become an intricate part of my life. The power of communication, the power of language & the power of performance combined with the ability to reach out to others & touch them has been the guiding light throughout my life.

In New Zealand I trained to be a Teacher in Music, English & Sports. I furthered my Education & completed an additional Diploma in Sports & Fitness. Opportunities opened new horizons for me in England where I specialised in Music & Communication Psychology. Curiosity got the better of me so I studied TEFL (Teaching English as a foreign Language) to work, travel & explore Europe.

I secured a position at Airbus, Germany & thus began my career that took me onto a journey around Europe. I have had the fortunate experience to work in Germany, Spain, France, Austria, Italy, England, Switzerland & Poland.

In 2014 I completed my Degree in German Studies.

Experienced as:
Company Director, Communication Coach, Human Resource Manager, Personal Developer, Lecturer, Motivation Coach, English, Music and Sport Teacher, Fitness Trainer, TEFL Trainer, Musician, Performer, Moderator and Presenter with 27 years of international experience in 7 countries.


My coaching fields of expertise are:

  • 360° Communication & Motivation strategies
  • Management & Leadership toolboxes
  • Management & Employee sustainability
  • 360° Change Management processes, implementation & sustainability
  • Psychological profiling
  • Team development
  • Employee development
  • Human Resources & Personal Development
  • Pitch training
  • Career coaching & Application management
  • Appraisal processes & sustainability
  • Evaluation & Assessment procedures
  • Resolution management & Conflict management
  • Time management
  • Work-Life Balance management
  • Rhetoric, Presentation & Moderation skills
  • Career & Lifestyle
  • Business English
  • Music coaching “power of voice”
  • Cooking & Communication
  • Architecture
  • Celebration of music in all cultures
  • Contemporary guitar
  • Modern, classical & jazz piano
  • Performing, singing on stage & at events
  • Entertaining guests
  • Indian, Thai & European cuisine
  • Interior design
  • Literature
  • Meeting new people
  • Nature & wildlife
  • Theatre
  • Travelling


  • C12Kommunikation | Founder | Managing Partner

    Communication & Personal Coach

  • Business Coaching Specialist

    AIRBUS, Daimler Chrysler, EADS, Grabarz & Partner, Imtech, Unilever, Pilot Group, Peter Schmidt Group, Bauerfeind, FSG Hamburg, MMK, Phillips, Canon, Grossmann & Berger, Mckinsey, Lever Faberge, Springer & Jacoby, Springer & Jacoby Digital, Kolle Rebbe, Jung von Matt, Flemming Pfuhl Advertising Agency, Peek und Cloppenburg, Vion, Stage Entertainment, Lucy Planning, Gaia, Elefant 7, Reinhard Branding, Pilot Media, MMK Kommunikation, Stage Holding, Hafentheater, KMF Werbung, Vion GmbH, Somann & Scheller, Arc Interactive, Shaken not Stirred Communication, Kreiger & Partner, Deutsche Angestellten Akademie, Oracle GmbH

  • Lecturer & Teacher

    Music, English, Sports, Geography, History, TEFL.

    In Germany, England & New Zealand