Roy Thomson Hall is located in downtown Toronto on a 2.5-acre site bounded by King, Simcoe, and Wellington Streets. It responds architecturally to the adjacent Downtown West development planned by Marathon Realty Company, for which the same architectural team will also be responsible. A city park, to be located west of the hall, will provide an attractive and dramatic landscaped setting to unite the commercial buildings and the concert hall.

Roy Thomson Hall is one of the world's finest concert halls, possessing acoustic excellence, a high degree of intimacy and comfort, and good sight lines. The concept, which emerged after numerous study models and lengthy consultations with the acoustics consultant, Dr. Theodore Schultz of Bolt, Beranek and Newman, was a shield-shaped plan with the stage located at its narrow end. There are three levels of seating: on the main floor, mezzanine, and balcony. The mezzanine and balcony levels consist of a series of petal-shaped modules fanning around the auditorium and continuing behind the stage. This configuration creates a feeling of intimacy that is often lost in halls of this size. Roy Thomson Hall, the new home of the Toronto Symphony and Mendelsohn Choir, provides a total of 2812 seats in the main auditorium compared with 2765 seats in the old Massey Hall building which it replaces. Of this, 2693 are subscription, compared with some 2200 in the existing hall. As well, 300 seats are available in the Rehearsal Hall for small recitals. In the concert hall itself, no seat is further than 107 feet from the stage. By comparison, the closest seat in Boston's famed Symphony Hall is 104 feet from the stage. Sight lines have been carefully calculated so that every member of the audience has an unobstructed view.

Roy Thomson Hall is constructed with a double shell, shielding the performers and the audience from all external noise, and the acoustics have been developed utilizing every resource of today's technology. The reverberation times are controlled by 122 coloured banners, which can be raised or lowered from the ceiling by a unique control system. As a result, the ceiling becomes the most theatrical aspect of the hall, changeable for different programs, brilliant in colour and endlessly fascinating to gaze at, like the ceilings of the great opera and concert halls of the past. The audience and the orchestra rightfully provide the remaining drama and colour in the hall. Other elements of the hall - the walls, balconies, and seating of concrete, fabric, silver metallic paint and chrome - provide a warm but quiet background to the orchestra, audience and ceiling display. The oval shaped auditorium and its square base are connected and enclosed by a draped, net-like structural canopy, sheathed in glass. The translucent qualities of this material not only lighten the building mass but also allow lobby activities to be visible from the exterior. As a result, the glass canopy appears as a constantly shifting myriad of gem-like facets, either reflecting or transparent, depending on the angle of light and changing in appearance with the season, weather and time of day. Through the canopy, the mirror-clad walls of the auditorium itself reflect the audience to the outside. The patrons are the spectacle as they move up the escalators or down the tiered stages of the lobbies to the main floor. At night Roy Thomson Hall reveals a warm sparkle from the lobby areas which, combined with the movement of the audience, seems to radiate and anticipate the excitement of the performance within.