cees mulder


ing. cees mulder
acoustic consultant



Welcome to my website. I am a consulting engineer specialized in room and electro acoustics, with a focus on performing arts. I am based in Rotterdam, The Netherlands. My starting point is that a room should sound good, my philosophy is that architecture, volume, shape and finishes, determine the acoustics and thus how a room sounds. The focus should be on shaping and fine shaping the architecture such the architecture serves the acoustics, but without compromising on the design, in order to deliver both a fine sounding and good looking room. A design should be made with knowledge of how a room behaves, how its surfaces behave (shape and finishes) and above all common sense. In stead of working mainly with so called “sophisticated” acoustic simulation tools (I do not exclude those!) I prefer working with 3D design programs with special plug-ins to investigate the acoustic behaviour of the room's geometry and from there acoustically tune the architectural shape and orientation of surfaces.


My field of activities ranges from:

  • room acoustic/architectural design:

      concert and opera halls, theatres, auditoriums, large spaces, etc.: definition of shape of and material to be used, calculations and/or simulations for optimizing geometry, creating reports and/or defining specifications;

  • on site consultancy:

      a thorough study is not always required. At times simple practical solutions or advice are enough to keep in line with the budget. On site or from drawings acoustic measures can be discussed with the architect, the technical staff or the users. This can be ideal for rooms with a lower acoustic complexity. Acoustic quality is equally influenced by the configuration and set-up for musicians with respect to the room;;

  • acoustical tuning of rooms:

      by architectural, theatre technical and/or electro acoustical means, and even by re-thinking the position of musicians on stage;

  • room acoustic and electro acoustic measurements:

      for an investigation prior to a project, because of problems or verification after commissioning, creating reports with results and when required verification to standards and indicating recommendations;

  • expertise:

      variable acoustics for theatres, concert halls and opera halls by means of reverberation amplification (negative absorption);

  • acoustic and functional design of sound systems:

      creating block diagrams and descriptions of systems, performing calculations and/or simulations, creating reports and/or defining specifications;

  • tuning and commissioning of sound systems;


In the field of acoustics for performing arts venues there is a mutual collaboration with Kahle Acoustics from Brussels


  • Secondary education higher level (1979 - 1985)

  • University of Applied Science Utrecht, electronics (1985 - 1991)

  • Sound balance, one week course at Royal Conservatory The Hague (1995)

  • Higher Course Acoustics Antwerp (1995 - 1996)

  • Electro Magnetic Compatibility, six day post academic course (1997)

  • Business Orientation, Philips, twelve days (1999)


  • Peutz consulting engineers,
    Mook, The Netherlands (Feb. 1993 - June 1994)

  • Philips Projects BV,
    Eindhoven, The Netherlands (Nov. 1994 - Sept. 2000)

  • Lichtveld Buis & Partners BV,
    Nieuwegein, The Netherlands (Oct. 2000 - Feb. 2006)

  • Theatre Academy Amsterdam,
    teacher acoustics (2001 - 2011) and audio electronics related topics (2007 - 2011)

  • independent consulting engineer since 2006

  • collaborative consultant at Kahle Acoustics,
    Brussels, since October 2010

  • University of Antwerp,
    teacher acoustics at the faculty of design science, architecture (2014 - onwards)

  • Karel de Grote Hogeschool Antwerp,
    teacher acoustics at the multi-media department (2016 - onwards)


  • AES (Audio Engineering Society)

  • NAG (Acoustic Society of The Netherlands)

  • VPT (Dutch Society of Stage Engineering)