connexion

1. The acoustic design of
Connexion@Nexus
a case study by
Amos Tan Chi Yi 0318330
Bridget Tan Su Ting 0318370
Chia Sue Hwa 0317920
Khor Yen Min 0318149
Natalie Ki Xiao Xuan 0318918
Philia Chua Yi Xian 0318936
Too Mun Fai 0318214

2. Objective of study
“Is Connexion@Nexus a good
auditorium design for its intended
purpose?”

3. Connexion@Nexus
298 seat auditorium
1022.77 cubic metre volume
Built in 2014
Multi-purpose auditorium

4. View of auditorium house from stage

5. View of stage from auditorium house

6. View of auditorium house from stage

7. Connexion@Nexus
298 seat auditorium
1022.77 cubic metre volume
Built in 2014
Multi-purpose auditorium
Plan

8. Connexion@Nexus
298 seat auditorium
1022.77 cubic metre volume
Built in 2014
Multi-purpose auditorium
Reflected Ceiling Plan

9. Connexion@Nexus
298 seat auditorium
1022.77 cubic metre volume
Built in 2014
Multi-purpose auditorium
Longitudinal section

10. Multi-purpose auditorium?
“Annual General Meeting (AGM), Business Presentation,
Concert, Conference, Convention, Press Conference,
Product Launch, Product Talk, Seminar, Training
Sessions”
-Connexion@Bangsar Brochure

11. Acoustical analysis
1. Auditorium form and layout
2. Materials
3. Acoustic treatments & components
4. Sound & noise sources
5. Sound propagation and related
phenomena

12. Auditorium form and layout
Shape and massing –
curvilinear, fan/elliptic shape
Coverage of 140 degrees allows
audience to perceive higher
frequency sounds, with optimal
arrangement of seats.

13. Auditorium form and layout
Shape and massing –
curvilinear, fan/elliptic shape
Design has issues with sound
reflection and the creation of a sound
concentration area at the centre-back
of the auditorium.

14. Auditorium form and layout
Levelling of seats- Raked
seats and raised stage
Design defines relationship between
speaker and audience, and direct
sound is not impeded by presence of
other members of audience.
Connexion@nexus
layout
Raised stage
reduces issue
Issues with
sound

15. Auditorium form and layout
Ceiling reflector panels – at
a constant angle
Strategy to use the most out of
available sound source by directing
reflected sound towards audience.
Constant angle is problematic and
inefficient.
Expected sound reflection from ceiling reflector panels

16. Materials
Absorbent and reflective
All materials transmit, absorb and
reflect sound to a degree.
Reflective materials defined as having
absorbent coefficient at 500Hz of
< 0.1
Absorbent materials defined as having
absorbent coefficient at 500Hz of
> 0.1

17. Materials
Plan – Liberal use of
absorbent materials
The stage being reflective allows for
redirection of sound, however it is
stalled by overuse of absorbent
materials in the house.

18. Materials
Section- Liberal use of
absorbent materials
Inefficient usage of reflective and
absorbent materials especially near
stage will lead to problems with
“liveliness”

19. Acoustic Treatments
& Components
Absorbent and reflective
To combat perceived or imagined
echoes and sound concentration area,
the auditorium has extensive acoustic
treatment strategies that are
overwhelmingly geared towards
sound absorbency.

20. Acoustic Treatments
& Components
Acoustic wall panels
Acoustic wall panels are built with
layers upon layers of sound absorbent
material, and apparently seeks to
combat the creation of the
aforementioned sound concentration
area.

21. Acoustic Treatments
& Components
Acoustic wall panels -
absorbent
Acoustic wall panels are built with
layers upon layers of sound absorbent
material, and apparently seeks to
combat the creation of the
aforementioned sound concentration
area.
Section of acoustic
panel and wall

22. Acoustic Treatments
& Components
Stage-Reflective
Stage is built with sound reflection in
mind, as all components have a very
low sound absorbency coefficient.
Section of stage

23. Acoustic Treatments
& Components
House floor -Absorbent
The floor of the auditorium house is
covered with a thick layer of carpet on
top of a rubber layer. This rubber
layer dissipates sudden sounds.
(footsteps, etc)
House floor section

24. Acoustic Treatments
& Components
House floor -Absorbent
The floor of the auditorium house is
covered with a thick layer of carpet on
top of a rubber layer. This rubber
layer dissipates sudden sounds.
(footsteps, etc)
Distribution of
carpet

25. Acoustic Treatments
& Components
Curtains – Fire rated
absorbent
Thick curtains of the same material
are used for the back stage, centre
parting and festoon curtains and are
highly absorbent materials.
Back stage, centre parting and festoon curtains

26. Acoustic Treatments
& Components
Seating – upholstered
Common practice is to have seating
upholstered with material that has
roughly the same absorbency
coefficient as a human being to ensure
identical sound however large the
attendance.
Upholstered seating

27. Acoustic Treatments
& Components
Reflective ceiling panels
Constructed with gypsum board,
giving it adequate reflective qualities
to redirect sound unto the audience.
Reflective ceiling panels

28. Sound & noise sources
External and internal noise
Connexion@Nexus exhibits noise
issues due to its design.

29. Sound & noise sources
External and internal noise
Connexion@Nexus exhibits noise
issues due to its design.
Sources of noise (plan)

30. Sound & noise sources
External and internal noise
Connexion@Nexus exhibits noise
issues due to its design.
Sources of noise (section)

31. Sound & noise sources
External and internal noise
Connexion@Nexus exhibits noise
issues due to its design.
Sources of noise (reflected ceiling plan)

32. Sound & noise sources
Sound locks & doors -
insufficient
Only one sound lock is provided in
the auditorium, and is located at the
primary entrance. Doors are made of
reflective and of very low STCs,
allowing noise to easily pass through.
No sealing of any kind present.
Doors have door dampers installed.
Sources of noise (plan)

33. Sound & noise sources
Air conditioning diffusers –
narrow and long and noisy
A loud noise can be heard whenever
the air conditioning is switched on,
with an SIL of around 55 dB.
Diffuser design increases air velocity
due to Venturi effect, and thus creates
a louder noise.
Sources of noise (plan)

34. Sound propagation &
related phenomena
Sound paths, reverb time, etc.
Analysis of sound propagation
throughout reveals the effectiveness of
the acoustical design of the auditorium.
The auditorium has no echoes, allowing
speech to be easily discerned.
However, it has a reverberation time far
too short for its use.

35. Sound propagation &
related phenomena
Sound intensity level (SIL)
Recorded on site, an area of sound
concentration is noted at the centre-
back. This is an expected consequence
from the unusual shape of the
auditorium.
SIL measurement of the auditorium

36. Sound propagation &
related phenomena
Sound intensity level (SIL)
Recorded on site, an area of sound
concentration is noted at the centre-
back. This is an expected consequence
from the unisual shape of the
auditorium.
SIL measurement of the auditorium

37. Sound propagation &
related phenomena
Sound intensity level (SIL) -
countermeasures
Absorbent materials mitigate actual
effect, with the resultant concentration
area being only 3 dB louder than the
surroundings.
This is considered as inconsequential.
SIL measurement of the auditorium

38. Sound propagation &
related phenomena
Reflection of sound
Relatively few sources of significant
reflected sound due to overuse of
absorbent materials.
This will contribute to suboptimal
reverberation time.
Sound propagation towards Rows 1, 6 and 11.

39. Sound propagation &
related phenomena
Reflection of sound
Any sound delay above 40ms in
speeches and above 100 ms in music
are considered as echoes. The longest
time delay is only 13.8ms.
This auditorium does not have any
echoes.
Time delay calculation
Time delay:
2.1 ms
Time delay:
13.8 ms
Time delay:
8.23 ms

40. Sound propagation &
related phenomena
Reverberation time
Auditoriums should exhibit a
reverberation time of around 1.4
seconds.
Connexion@Nexus has a
reverberation time far too low, at 0.3
seconds. This is considered a “dead”
space
This calculation is based on the
absorbency coefficient as listed in the
report.
Ideal reverberation time
Connexion@Nexus
Reverberation time

41. Sound propagation &
related phenomena
Reverberation time
Auditoriums should exhibit a
reverberation time of around 1.4
seconds.
Connexion@Nexus has a
reverberation time far too low, at 0.26
seconds.
Reverberation time calculation

42. Sound propagation &
related phenomena
Acoustical defects
The auditorium exhibits other defects,
with flutter echoes being noted on
stage due to parallel reflective
surfaces.
The ceiling reflectors are not of a
efficient design, as other reflectors
reflect sound towards a wall covered
with absorbent acoustic panels.
Acoustical defects

43. Connexion@Nexus as
a speech auditorium
Music is not recommended
The auditorium exhibits features better
suited for voice. Lack of echoes allow
audience to perceive every word
clearly. The depth of only 15.5m
allows voice to be heard unamplified.
The extremely short reverberation
time is an issue. People will not
perceive voices to be “pleasant” or
“rich”.

44. Objective of study
“Is Connexion@Nexus a good
auditorium design for its intended
purpose?”
No

45. thank you