CS Audi - Case Study DRAFT

C A S E S T U D Y

1 ARCH 147 Evangelista

CHAN, Merrilyn |CRUZ, Carla|GAYOBA, Valerie|ROCHA, Regina|YAZON, Alexese

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I. Existing Conditions a. Brief History1

The College of Science was set up as a separate college of University of the Philippines Diliman on October 6, 1983 during the term of Senator Edgardo Angara as UP President. Presently, the college is comprised of eleven constituent units, namely: National Institute of Geological Sciences (NIGS), National Institute of Molecular Biology & Biotechnology (NIMBB), The Marine Science Institute (MSI), National Institute of Physics (NIP), Natural Sciences Research Institute (NSRI), Institute of Biology (IB), Institute of Chemistry (IC), Institute of Environmental Science & Meteorology (IESM), Institute of Mathematics (IM), Materials Science & Engineering Program (MSEP), and Science & Society Program (SSP).

Since then, it has occupied a 21.9 hectare area in the south sector of UP

Diliman adjacent to the UP [South] Technology Incubation Park. On 8 December 2006, the area was declared as the National Science Complex by President Macapagal-Arroyo by an executive order (EO 583). It is currently being completed at a total cost of 1.7 billion pesos, using funds that have been provided by the national government in FY 2006, 2008 and 2009. Construction started in March 2007 with the final building to be completed in January 2012.

b. Architect/Acoustical Consultant

The College of Science Administration Building, which

houses the College of Science Auditorium—more familiarly called

CS Audi by UP students—was designed by Architect Francisco J.

Nakpil, son of Juan J. Nakpil, the Philippines’ first National Artist

for architecture.

1 College Info. The U.P. College of Science. Web. 20 Feb. 2011.

<http://www.science.upd.edu.ph/index.php?option=com_content&task=view&id=12&Itemid=27>.

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c. Use/Activities

The CS Auditorium is primarily used as a lecture space for GE subjects

offered by the College of Science, namely for the courses of Natural Sciences 1,

Natural Sciences 2, and Science, Technology and Society (STS). Below is the schedule

of classes held in the CS Auditorium for the second semester of AY 2010-2011:

Other uses include functions, special lectures, seminars, etc. primarily of the

College of Science, and secondarily of users outside of the College, as this space is

rentable.

d. Average Number of Users & Seating Layout/Capacity

The average number of users is 100 people at any given time (i.e., class

lecture), though seating capacity is double that figure. The auditorium can seat 220

people. Additional mono-block chairs are stacked at the back of the theatre—this

enables the venue to accommodate more than the designated 220 people seating

capacity.

Typical Seat Plan.

Typical Seat Plan

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e. Location of Sound Source/s

Stage View

The main location of the sound source is the speaker who is situated on the

stage. To improve the audibility of the sound, speakers and sound-enhancing

equipment are used.

f. Average Distance (Source to Receiver)

The average distance from the sound source to a receiver seated at the

center of the seating area is approximately 6 meters.

g. Use of Ceiling Reflectors

The CS Auditorium makes use of ceiling reflectors that are of plywood

material. These are tilted in such a way that sound distribution is maximized

throughout the space.

Ceiling Reflectors

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Spot Detail of a Typical Reflector

The reflector panels are approximately tilted at nine degrees from the

horizontal. Pin lights are installed at their midpoints, and they are suspended from the

ceiling slab at a distance of about 0.25 meters. Typically, the panels are ½” thick plywood

panels 1.50 meters in length on 2” x 2” wood nailers.

h. Use of Splayed Walls

The walls use ½” thick and 0.20 m wide tanguile wood planks on wood nailers spaced at 0.25 meters on center in order to treat them acoustically and effectively diffusing sound throughout the space.

Wall Panels in Actuality

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Spot Detail of a Typical Wall Finish

i. Slope of Floors

The slope of the floor is at approximately 6.3 degrees. The floor is stepped at

approximately 0.11m per riser.

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j. Height of Stage

View from the stage and view of the stage upon entry through right entrance of auditorium.

The height of the stage is approximately 0.90 meters.

k. Sound Paths (Geometric Acoustics)

Sound Paths in Plan

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Sound Paths in Section

The sound is transmitted and reflected off the walls and the ceiling of the

auditorium rather well. The rear wall of the auditorium is, however, treated to

diffuse sound. This shall be addressed later on in the recommendations.

l. Assumed/Perceived RT

Below is the calculated absorption of the auditorium, together with the

assumed reverberation time.

area (sq.m) material NRC absorption

floor 152 Vinyl Tiles & Rubber on Concrete 0.05 7.6

ceiling 263 1/2 inch thick plywood 0.3 78.9

stage 13.5 1/2 inch thick plywood 0.3 4.05

rear wall 14.4 Wood Panel Diffusers 0.3 4.32

side wall 45.864 Tanguile Wood Planks 0.4 18.3456

27.89736 Spraytex Textured Concrete 0.08 2.2317888

curtains 3.6 2 Layer Suede Curtains 0.55 1.98

window 1.68 0

door 2.4 0

front wall 13 Tanguile Wood Planks 0.4 5.2

curtains 8.32 0

seats 100 Leather Upholstered Seats 0.5 50

A 172.6273888 sabs

REVERBERATION TIME Volume = Floor Area * Average Height

684.45 cubic meters

RT = 0.16V/A

RT = 0.634384 seconds

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Using a decibel meter, several trials were made in the auditorium in

different locations as specified in the diagram below to determine where best and

worst spots with respect to transmission of sound were:

The results are as follows:

CONDITION: No sound source/speaker talking

seat area trial 1 trial 2 trial 3 average

1 56.3 57 56.5 56.6

2 51 51.4 51.2 51.2

3 53.6 53 53.3 53.3

4 49.1 50 49.5 49.53333

5 48 50 49 49

6 47 48 49 48

CONDITION: Normal Speaking Voice

1 68.9 69 73.9 70.6

2 67.8 75.3 72.3 71.8

3 67 64 67.5 66.16667

4 67.7 67.4 68 67.7

5 65 64 60 63

6 67 67 63 65.66667

CONDITION: With Microphone

1 85.6 88.3 83.2 85.7

2 74.5 86.8 77.2 79.5

3 83.9 84.6 84 84.16667

4 84.6 74.2 82 80.26667

5 80.4 85.4 82.4 82.73333

6 73.9 80.4 83.7 79.33333

LOCATION: Center Aisle

CONDITION: without microphone

trial 1 trial 2 trial 3 average

70.7 68.6 66.3 68.53333

75.9 76.6 83.7 78.73333

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The results show that when the sound source is transmitting sound without

any artificial amplification technology, the area designated “2”, nearest to the sound

source is the optimum spot to be in. Meanwhile, when sound amplification systems

are used, the area designated “3”, the areas on the sides closest to the speakers, are

the locations where the sound is loudest.

m. Potential Acoustical Defects

Potential acoustical defects include perhaps the fact that the rear end of the

auditorium is treated with diffusive material when ideally it should be absorptive.

Also, noise coming from inside the storage room can be heard from the auditorium

space, even if noise coming from the auditorium proper cannot be heard when

inside the storage room. Apart from that, however, there are no major acoustical

defects present in the auditorium.

n. Noise Sources Within and Outside the Space

The noise from inside the space mainly comes from the HVAC or air

conditioning system and the 100 students seated inside the class. Outside of the

space, noise sources can come from people loitering in the atrium.

o. Type of Sound Amplification System

The sound amplification system used is essentially a combination central-

distributed loudspeaker system. A loudspeaker is installed right above the sound

source and secondary speakers are located around the auditorium, as will be seen in

the next section.

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Location of Speaker at the Center of the Stage

Left: Amplification System Control; Right: Wireless Microphone Control System

p. Location of Speakers

Two large speakers (Bose) are attached on the left and right walls of the

stage, just outside the equipment rooms. Two pairs of smaller speakers are located

on the front left and right side walls of the seating area and the left and right back

corners of the room. The main control room of the sound equipment is located in a

small room (tech booth) near the entrance of the auditorium.

Speaker Locations

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q. Lighting, AC, etc.

Lighting is composed of:

fluorescent lamps with egg crate baffles

spotlights (stand-alone units)

pin lights

emergency lights

Air conditioning units by Carrier are suspended on the right, left and rear walls. Smoke detectors are also installed.

r. Materials and Material Properties

Material Location Acoustic Properties Photograph

Rubber on Concrete Floor NRC: 0.05

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Vinyl Tiles Floor (Seats) NRC: 0.05

1/2 in thick plywood Ceiling NRC: 0.30

Spraytex Textured Concrete

Walls NRC: 0.08

Leather Upholstered Seats Seats NRC: 0.50

Tanguile Wood Planks Walls NRC: 0.40

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Wood Panel Diffusers Rear Wall NRC: 0.30

2-Layer Suede Curtains Stage/Side Walls NRC: 0.55

s. Auxiliary Spaces

Auxiliary spaces include the tech/media room located on the right of the stage, the storage room on the equivalent left, and the backstage immediately at the rear of the stage.

The tech/media room houses the controls for the sound systems (i.e., speakers,

microphone settings, etc.). It has surfaces that are not treated acoustically; they are highly reflective concrete surfaces. The door leading to the booth is louvered, which allows sound from inside the tech room to escape into the auditorium space.

The storage room is similar in size and shape of the tech/media room. It houses

the controls and switch panels for the electric circuits of the auditorium. Sound coming from the interior of the storage room is easily heard from the seating area.

The backstage is separated from the stage proper by two layers of suede fabric

curtains. It stores additional equipment and chairs, and the computer that is directly linked to the overhead projector. Wooden planks are installed on the lower half of the walls for diffusive purposes.

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II. Survey

Looking for different issues involving acoustics in the College of Science Auditorium,

the researchers had conducted a survey involving the users, 50 UP Diliman students who

have taken classes, a seminar or watched a play in the College of Science Auditorium.

Convenience sampling was used through a web survey.

Most of the respondents had used CS Auditorium as a venue of one of their classes,

namely, Natural Science 1 (NatSci1), Natural Science 2 (NatSci2) or Science, Technology and

Society (STS).

The diagram that follows was given to the survey participants to identify where they

normally chose to sat:

The results showed:

Most of the 50 participants sat at the area designated 4, in the middle sitting area. Twenty-six respondents (51%) choose to sit in the center of either right or left wing of the auditorium while the least and only two of the respondents (4%) usually sit in the front of either right or left wing. Ten respondents (20%) sit either at the left most or right most part

0

5

10

15

20

25

30

1 2 3 4 5 6 Other

25

11

28

35

1

Users' Seating Preference

Users

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of the auditorium, followed by the center at the front with ten percent of the respondents. The leftmost or rightmost area at the back, the center at the back, and the leftmost or rightmost seats in the front are chosen by eight percent, six percent, and four percent of the respondents, respectively.

As students, the most common factors to where students seat in a classroom are, the seatmates, the distance from the stage or the black/whiteboard, or the distance from the lecturer, and the position of air conditioner.

Thirty-three of the respondents (70%) say that the loudness of sound in the auditorium is average, twelve (26%) say it is loud, two of the respondents say the loudness of the sound is soft.

A majority of the participants found the clarity of sound to be average, while

the next big portion of them found the sound clarity to be clear. A few were

dissatisfied.

0

5

10

15

20

25

30

35

Very Loud Loud Average Soft Very Soft

0

15

34

20

Loudness of Sound

Users

0

5

10

15

20

25

30

Very Clear Clear Average Unclear Very Unclear

3

15

28

5

0

Clarity of Sound

Users

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More than half of the participants found the quality of sound to be average, while

sixteen of them found it to be pleasant. Only four participants said it to be unpleasant. Loudness,

clarity and quality could be attributed of course to the sound source, who is the lecturer. But the

Sound Amplification System is a big deal with regard to the sound heard by the receiver.

Twenty-five participants were satisfied with the lighting of the auditorium. Overall,

however, there was more or less no complaint about lighting.

0

5

10

15

20

25

30

35

Very Pleasant

Pleasant Average Unpleasant Very Unpleasant

0

16

31

4

0

Quality of Sound

Users

0

5

10

15

20

25

Very Satisfied

Satisfied Neutral Dissatisfied Very Dissatisfied

4

25

7

4

0

Satisfaction with Lighting

Users

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Most of the participants answered that if they had the power to change or improve

anything in the auditorium, they would do so with respect to the entrance and exit points of the

auditorium. The seats were also seen to have room for improvement, perhaps because getting

to a middle seat when the row is already more or less filled can prove to be a challenge,

especially since space is quite tight from row to row if the seats are not folded. Also, since there

is a center aisle, students usually opt to occupy the seats in the center. The seats also produce

creaking sounds, and some collapsible desks are dilapidated and no longer functional.

The auditorium’s sound system was also a popular choice in wanting improvement, but

this is perhaps due more to frequent technical difficulties than in actual acoustical defects.

Frequent noises heard within the auditorium included the murmur of students being the

most popular noise complaint, followed by the microphone feedback, then the sound of the air

conditioning system. Echoing, or more appropriately, reverberation, was the next complaint.

One student identified the creaking of seats to be something he noticed, and another

complained of the static noise coming from the sound system. Another noticed the “buzz” in the

room, most likely caused by the combination of sounds coming from the air conditioning and the

sound system.

A majority of the participants agreed that should there be a noise immediately beside,

behind or in front of them apart from the sound coming from the sound of the source (e.g.,

lecturer), they would notice it right away.

0

5

10

15

20

25

8

2321

17

6

10

Improvements Wanted

Users

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III. Recommendations

Reduction of Noise The diffusive area of the auditorium is not effective in absorbing and distributing the

sound. The plywood planks 1.20 meters above the ground is effective in absorbing low frequency sounds, however, high frequency sounds as well as noise from 100 students can't be abated by that alone. Acoustical blankets and fabrics should be added on the surrounding walls of the auditorium to increase sound absorption. These suggestions should hopefully reduce the “buzz” coming from the air conditioning units, and the surrounding murmur usually coming from the audience themselves. Manipulation of Sound through Reflectors

The back wall of the stage is comprised of a suede curtain and the same diffusive material from the surrounding walls of the auditorium. To increase the reflectivity of the sound from the stage, polished wooden doors should replace the curtains in accessing the backstage to the stage. Also, the diffusive plywood material on the walls beside the stage should be removed and left as bare concrete. Improved Circulation

Overall, the auditorium is highly accessible with 2 double doors for access and 2 fire exit doors at the back in case of emergencies. There is a sufficient number of aisles for the students to go around; 1.20 meters wide on the sides and 1 meter on the center aisle. Improved Seating Layout

Since the best sound quality can be found on the center, we proposed the removal of the center aisle and instead put 2 auxiliary aisles after 5 seats on the left and right sides of the auditorium. Change of Materials

There should be an increase use of absorptive materials on the diffusive walls to propagate the absorption of high frequency sounds. The same would be done on the back wall which is mainly diffusive in nature with its ribbed characteristics to increase sound absorption and prevent back reflections. Improved Sound Amplification Systems

Install built-in speakers to lessen eye-sores because of hanging speakers. Perhaps there could even be an upgrade of the system, to reduce frequency of feedback and the Acoustical Treatment in Auxiliary Spaces

The tech room and the equivalent storage should be made more sound-proof to lessen the possibility of sound emanating from that space from escaping into the auditorium proper. An anteroom could be devised, so that the auditorium can be more sound-proof and protected from external noise disturbances. Additional Storage Additional storage space can be rethought so that the mono-block chairs at the rear of the auditorium and other larger equipment will not remain exposed there as an aesthetic eyesore for the next few years.

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Optimum RT

The optimum RT would still remain to be 0.634384 seconds, whereas the optimum absorption is 173.83 sabines. Recommended Materials

Material Description Location Acoustic Properties

Photograph

Ecosoft Acoustic Carpet Tile

Durable

Fire resistant

Superior Sound Absorption

Stain Protector and Soil repellent

Seating area

NRC=.35

Sound Channels Acoustic Fabric

Moister and bacteria resistant

Anti-allergic

100% Solution Dyed Post-Consumer Recycled Polyester

Applied directly to surface

Back wall NRC= 0.15

Rubber Dot Smooth Tile

tiles are 500 x 500mm and 2.7mm thick. also available in static dispersion and noise reduction.

Ramp NRC=.05

Maple wood Tongue and Groove Stage floor NRC=0.15

Fireproof acoustic insulation foam

To be used in ventilation ducts sound insulation are required together.

Air conditioner ducts and vents

NRC=0.45

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Auditorium Seating

Fabric Upholstery

With collapsible desk

Seating Area

NRC=0.60

Vinyl Luminous Nosing

Coextruded anti slip vinyl insert with 8mm luminous strip used to highlight edge of step in case of power failure .

Tread nosing

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CS Audi - Case Study DRAFT