Summary:

The Rose Theatre, Brampton is a state-of-the-art legitimate and community theatre with 980 seats. The building was built on top of a pre-existing parking garage and is located a mere 20 metres from a CN freight rail line. The main auditorium is in a horseshoe shape with a single shallow balcony designed for excellent sight lines and acoustic properties. A Secondary Hall is intended both as a separate venue for film, dance, recitals and also as a rehearsal space for the main auditorium.

Solution:

Theatre Acoustics

The Theatre is designed in a horseshoe shape to give every patron both excellent sight lines and a sense of intimacy. These features are complimented by the acoustics of the space; the sound is intimate, warm, clear and enveloping. These are all characteristics of great concert and performance halls. Each patron can clearly hear music and voice from the stage without amplification. Performers have commented on the wonderful acoustics not just after but during their performances!

The intimate acoustics were achieved by controlling background sound levels to very low levels and by providing sound reflecting panels around the proscenium, side and back walls. While some of the panels are designed to reflect sound into all areas of the audience ─ both from stage performers and from the orchestra pit ─ others are designed to provide diffusion of sound. Excellent uniformity of sound distribution and reverberant characteristics have been achieved.

Variable acoustics has also been provided ─ a series of curtains on the rear and side walls at the orchestra cat walk levels can be added or retracted to adjust the reverberation characteristics of the hall for different performances ─ a “dry” hall for speech and solo instruments a “livelier” hall for music and music theatre.

Noise and Vibration Control for Railway Freight Trains

Railway freight trains are extremely noisy and generate ground-borne vibration which was perceptible as vibration at the parking garage roof deck. Air-borne noise from the trains provided a significant challenge and the usual room-within-a-room construction could not be employed. The building is supported by a transfer grid used to distribute the building loads to the pre-existing parking garage columns.

Exterior noise from the trains is controlled to meet the interior objective of RC 20 by providing a “floating” shell enveloping the entire building. Exterior concrete pre-cast panels are resiliently supported and resiliently connected back to the building and the entire roof slab was vibration isolated from the structure, controlling train noise to meet the interior design objective.

For railway-induced vibration, the building was supported on a transfer grid which was in turn supported by 300 mm thick rubber vibration isolation pads. The entire building, including exterior shell, stairs and elevators is vibration isolated. Measured vibration levels (and the noise radiated by vibrating surfaces) were controlled to well within the design objective.

Mechanical Noise Considerations

For mechanical noise, building envelope considerations limited available space for mechanical equipment, forcing mechanical rooms to be adjacent to the performance spaces. HVAC noise was controlled, in part by moving all of the stage HVAC to a location above the stage house. This greatly simplified ducting of supply and return and made possible a more efficient layout of HVAC. Noise from this equipment was controlled by duct silencers and vibration isolation for the mechanical equipment. The remainder of the building was supplied by two mechanical rooms on either side of the building. High quality duct silencing and vibration isolation has been supplied for these rooms.

Acoustically, the theatre provided an additional challenge as the rooms were to be multi functional accommodating theatre, musicals, corporate events, etc. The theatre and secondary hall auditorium were made variable through the use of retractable drapery to accommodate the varying acoustic requirements from live theatre as an acoustically dry space to musicals as an acoustically lively space.

Completion

This building has reached successful completion and all of the acoustic noise control objectives have been met.