Theatre Design - Auditorium

Primary objective = bring in as many people as possible within the optimum range of distances from the performance area, by:

• increasing the degree of encirclement in plan
• vertical layering eg. add in one or more tiers - this has the advantage of increasing number of seats without unduly increasing the distance from the stage. However, is more difficult to get good sightlines - shallow tiers help resolve this

Auditorium

Do not have the audience too obviously split - downplay the division of the balconies by placing the seats close to the edge...with railings designed to lean on.
Balconies to be no more than 2 seats deep

No reflective materials around the stage that would distract the audience (unless intentional)
Advantages of balconies:

• bring more people visually closer to the stage
• not so obvious when there are lots of empty seats (eg. can close off the top tiers) - better atmosphere

Seats

• audience in balconies will be looking down, not reclining
• balcony edges should be comforable for leaning on
• ideal scenario would involve adjustable seating (heights) in the top rows, moveable seats like the Q theatre

Visual & acoustic limits

Acoustics
Ideal scenario = no technology between actor and audience (eg. to enhance sound), and no background noise (NR of 25 or less?) - in particular mechanical/plant/plumbing noise

• NB.

Acoustics depend on:

• the behaviour of sound reflections and on the period of reverberation
• which in turn depends on:
• sound absorbed and reflected by the surfaces of the stage
• the volume of the auditorium and stage
• design of reflecting and absorbing surfaces can assist acoustics - old theatres with elaborate moulded plaster decorations which break up sound reflections mean a higher chance of being acoustically satisfactory than modern theatres with large areas of plain smooth walls and ceilings.
• no ceiling will mean there is no reflection back down into audience...
• artificial amplication is not usually desirable

Aids:

• sound absorbing material in the seats/balconies in circular theaters to avoid focusing of the sound
• minimise smooth surfaces on walls
• avoid deeply overhung balconies (best to restrict the depth from the front of the balcony to the rearmost seat under it to not more than twice the distance from the audience head level (eg. 1150mm from the floor) to the balcony sofit, at the front line of the balcony)
• reverberation will improve acoustics (providing not to much or too little)
• speech in auditoria of 300-12,000m3, the average reverberation time at mid frequencies should not be > 1.2s, or < 0.7s.
• is directly proportional to the volume of the theatre
• NB. a volume of around 3-5 m3 per seat gives about the right amount of absorption (audience plus materials) to provide reverberation times for ideal speech conditions - up to about 300 seats.

Vision

NB. 'P' is the lowest and nearest point which the whole audience should be able to see clearly

HD = horizontal distance (linear) between the eyes of the audience in consecutive rows

Average eye height is normally assumed to be 1120mm (but depends on seat design)

Balcony front height can be assumed to be 790mm.

Plays

• Visual limits - usually it is essential for the audience to be close enough to discern facial expressions so the usual accepted max = 20m (from centre of perfomance area)
• Acoustics - period of reverberation must be shorter for clarity of speech

Musicals, operas

• Visual limits - facial expressions are less important so the usual accepted max = 30m
• Acoustics - period of reverberation is longer for music and longer still for choral singing

Theatres: Planning Guidance for Design & Adaptation. Roderick Ham.Architectural Press: London. 1987

Seats

Allow at least 0.5m2 per person (seated):

• width-row spacing of 0.45m2 (or more)
• max of 16 seats per aisle OR 25 seats if one side exit door of 1m width is provided for every 3-4 rows
• exits/escape routes - 1m wide per 150 people (min width 0.8m)