The Concept Behind “Beautiful Sound”

We visited an architect last month who is designing a district-scale cultural centre. He asked us an acoustics question which we think our readers might find interesting. The question he asked was – “Does your company do “create beautiful sound” projects other than noise control projects? Both are acoustics work, but they seem to be different aspects.” he continued. “We certainly do both” we replied. The background knowledge of “create beautiful sound” vs. “eliminate unwanted sound” is interesting and is worth sharing with our readers.

There are two types of sound we can experience in our environment:

  • High-quality sound or “beautiful sound” which the architect mentioned above. It refers to the sound what we enjoy, admire and praise.
  • Unwanted or displeasing sound. It is considered to be an unpleasant sound which creates nuisance in an environment.

Can we create/make “beautiful sound”?

As an acoustics specialist, we would tell you the answer is “No”. We cannot create/make sound to be beautiful. The person who sings or the musical instrument the musician plays define the sound quality. However, we can create/design a built environment to optimise the room acoustics sound effect so as to deliver a melodious music to audiences.

Consider a classical orchestra concert hall as an example of a high-quality sound requirement. It is desirable that the music of an orchestra concert be rich in layers rather than being dry. Is there a way to make dreams come true? Materials play a significant role in the acoustics of concert halls. The same materials used in a space with good acoustics could be made to sound worse if they were arranged in a different way. In general, however, hard, reflective materials are ideal for concert hall acoustics. The use of concrete, metal, wood and curtains is critical in the acoustics design process. This is because the orchestra needs all the reflection and reverberation that it can get to make the sound richer. The interaction of these complex elements determines if the concert hall is a successful acoustical design.

Hong Kong Tsuen Wan District Hall - An Example of Good Acoustics Design

How about the control of unwanted sound?

Let’s take office environment as an example, one will come across quite a lot of different types of noise sources. Like the duct-borne noise from the air-conditioning grills, the break-out noise from the ductworks if there is no ceiling overhead, the break-in noise from the outside road traffic, railway noise through the windows, the structure-borne noise and vibration from the plant installed on the roof or the plant rooms, as well as the noise coming from adjacent tenants. All these types of noise will contribute a negative impact to the work environment, lower employees’ efficiency and may even adverse that pose a long-term influence on our emotion. Proper acoustics treatments are required to control and adjust the above nuisances.

With appropriate acoustic treatments to the noise sources, their transmission paths and the receivers, such as installing attenuators to control the duct-borne noise, wrapping the ductworks to control the break-out noise, selecting high performance glazing for window facades to control the break-in noise, installing resilient pads and / or springs for the plant to reduce the structure-borne noise, as well as enhancing the isolation performance of wall partitions to impede noise transmitting between rooms, the working environment in the office can be significantly improved. It helps create a pleasant work environment.

In most projects, however, these two aspects are not independent of one another. An example of this would be the acoustics design for the lecture hall at the Hong Kong Palace Museum. Major functions of this lecture hall are lecture presentation, cinema and school performance. The clarity of speech is of the utmost importance in this space. Considering that all lectures, speeches, and performances will be accompanied by amplifiers, absorptions on the walls and ceilings have been provided in order to create a space with low reverberation. A comprehensive acoustic design does not rely solely on absorption as an acoustic treatment. Noise level inside the lecture hall should also be controlled at an acceptable level. Other external noise sources contribute to the total sound levels in the lecture hall, of which the noise produced by the HVAC system is the most significant. The mitigation of noise from HVAC systems and from other sources is also an important part of acoustic design for lecture halls in order to optimize the acoustics sound effect.

Sometimes, the acoustics requirement may not be that high, but all enjoy …

Photo Credit

File:Sydney Opera House concert hall October 2018.jpg” by Nick-D is licensed under CC BY-SA 3.0.

kids’ music performance” by citymaus is licensed under CC BY-ND 2.0.

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