Audio Visual Design Guidelines

Design Criteria

13 views November 19, 2019 aetm 0

It is important to know what constitutes acceptable acoustics for learning spaces. A range of standards are available to designers which provide definitions and measurements to ensure that spaces are acceptable. 

Reverberation and Background Noise

AS/NZS2107 is the local standard which clearly defines design sound levels (LAeq) and reverberation times (RT60) for a comprehensive range of spaces in Australian and New Zealand buildings. 

For most spaces there is a balance to be struck for background noise levels.  Where background noise levels are too high there is potential for speech intelligibility to be impacted. However, background noise is also important for noise masking, which is an important factor in speech privacy. 

Where background levels are too low, speech privacy could be impacted meaning either additional treatment is required to building partitions, or a noise masking system may be required to increase background levels.  This would normally only be a consideration in a teaching environment where students are likely to be breaking into smaller project groups or in general workplace settings.

Similarly, the reverberation criteria is aiming to strike a balance between spaces being too reverberant (or lively) and too dead (or dry). A space with a higher reverberation time typically promotes higher noise levels during activity, which can impact on speech communication. Spaces which are used for dedicated audio or video conferencing may benefit from a lower reverberation time to support their functionality. Spaces with activities which result in high levels of noise may also benefit from a lower reverberation time to assist with noise control and reduce the effects of fatigue on users. 

The table below from standard AS/NZS2107 summarises a range of spaces typically encountered in educational organisations. This list is not exhaustive, please refer to AS/NZS2107 for additional spaces. 

Type of occupancy/ activity Design LAeq  Range (dB(A)) Design RT60 (s)
EDUCATION BUILDINGS
Art/craft studios 40-45 <0.8
Audio visual areas 35-45 0.6-0.8
Computer rooms

  • Teaching
  • Laboratories
40-45

45-50

0.4-0.6

0.4-0.6

Conference rooms 35-40 0.6-0.7
Drama studios 35-40 Curve 1*
Engineering workshops (Teaching) <45 (Note #1)
Interview/counselling rooms 40-45 0.3-0.6
Laboratories (Teaching) 35-45 0.5-0.8
Lecture rooms up to 50 seats 30-35 Curve 3*
Lecture theatres

  • Without speech reinforcement
  • With speech reinforcement
30-35

30-40

 

Curve 3*

Curve 3*

(Note #3)

Manual arts workshops <45 <0.8
Music practice rooms 40-45 0.7-0.9
Music studios 30-35 Curve 2*

(Note #3)

OFFICE BUILDINGS
Board and conference rooms 30-40 0.6-0.8
Meeting room (small) 40-45 <0.6
Video/audio conference rooms 30-40 0.2-0.4
PUBLIC BUILDINGS
Concert and recital halls (Note #3) (Note #3)
Courtrooms 30-35 Curve 1*
Video interview rooms 30-35 0.2-0.4

# Notes (from AS2107):

  1. Reverberation time should be minimized for noise control.
  2. Certain learning spaces, including those intended for students with learning difficulties and students with English as a second language, should have reverberation times at the lower end of the range. 
  3. Specialist advice should be sought for these spaces.
  4. *Curves: Refer AS/NZS2107 Appendix A for a guide to reverberation times in these spaces.

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