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Noise-th

In Chonburi, a motorcycle noise dispute turns violent and results in shootings

In Chonburi, a motorcycle noise dispute turns violent and results in shootings
In Chonburi, a motorcycle noise dispute turns violent and results in shootings

One man was hospitalized with a gunshot wound after a violent altercation and shooting broke out in Chonburi over a disagreement over the loud noise of a revving motorbike.

Tensions between two groups erupted in Soi Malaithong, Na Pa subdistrict, in the Mueang district of Chonburi, following claims of deliberate provocation. It started when a man named Oat was testing out a customized motorcycle close to a store. Ter, the shop owner, became enraged when the bike’s high torque caused it to rev loudly and perform a wheelie. He thought Oat was trying to provoke him on purpose.

In retaliation, Ter and five other men visited Oat’s relative Hut’s house and demanded an explanation. The violent attack on Hut and Oat was caught on CCTV, with Ter breaking Hut’s head with a dustpan. Oat begged for a calm discussion, but the attackers persisted in their attack.

The situation allegedly worsened after Ter sent derogatory messages about Hut’s father, Jeab, following the attack. In retaliation, Jeab went to Ter’s shop with Hut and Oat to confront him. Ter allegedly pulled out a gun, chambered a round, and pointed it at Jeab during the ensuing argument. He struggled when Jeab tried to disarm him. Then, as Jeab was still struggling with him, Ter fired another warning shot into the air, striking Jeab. He had to be admitted to the hospital due to severe injuries sustained when the bullet went straight through his body.

Ms. Chulaporn, Jeab’s sister, has demanded justice, claiming that her nephew was merely testing the motorcycle and did not purposefully rev it. She described the argument as a miscommunication that had been exaggerated and refuted assertions that it was the result of an old-fashioned rivalry.

What would have happened if someone had died? Money couldn’t compensate for it. Concerned for her family’s safety, she stated, “I would demand the same in return if my brother had been killed.”

By examining CCTV footage and witness accounts, police are looking into the incident. In order to decide on suitable charges and stop additional violence, authorities are working. Jeab is still in the hospital getting better from his gunshot wound.

References

www.aseannow.com

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Environment Home Noise-th

Dust and noise disturbance from a luxurious condo in Pattaya

Dust and noise disturbance from a luxurious condo in Pattaya
Dust and noise disturbance from a luxurious condo in Pattaya

The construction of a luxurious condominium in the Taphra Ya 9-15 area of Pattaya, which will rise more than 60 stories, has alarmed locals and rental operators.

Residents have been inconvenienced by the dust and noise from the construction site for more than two years, but local authorities have not offered any support.

52-year-old Taphra Ya 9 business owner Chalida voiced her annoyance, saying the construction has resulted in constant noise and dust problems. She said that because of the intolerable noise levels, which can occasionally last until midnight, many residents are slowly leaving.

Chalida gave reporters video footage showing the detrimental effects of the noise and dust from the construction site, as well as her unsuccessful attempts to lodge complaints with the Pattaya City Council and other authorities.

 

Those living on the seventh floor, which has been completely evacuated because of the noise and dust from the cement pouring on the nearby streets, are in an especially bad situation.

 

The extent of the issue was demonstrated by the thick dust layers that reporters saw on windows and floors, as well as the cracks in the surrounding buildings.

Additionally, the widespread dust has caused respiratory problems for housekeepers and employees, requiring the constant use of face masks. No agency has intervened to address these health issues in spite of their difficulties.

 

Chonburi MP Yodchai Phungporn recently paid a visit to the location to hear the complaints of locals and business owners.

 

According to Siam Rath, he intends to bring their grievances about the dust and noise to the Land and Environment Committee of the House of Representatives for additional action.

References

https://aseannow.com

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Noise-th

A few observations regarding Bangkok traffic

While it may look very similar, Bangkok’s transportation management is worlds apart. PHOTO BY FRANK SCHUENGEL

We recently traveled to Thailand, where we had the opportunity to witness firsthand the traffic in and around Bangkok, the country’s capital. We discovered some intriguing similarities and differences with Metro Manila.

Quite busy but polite. Although Bangkok’s traffic can be congested, particularly during rush hour, there aren’t many parallels between this city and Metro Manila beyond that.

Behind the wheel, people seem to be much more polite and relaxed here. There are plenty of spaces in the traffic, even during peak hours, unlike in Metro Manila, where it would be impossible to squeeze a single peso coin between the car in front and the one behind it.

Better lane discipline, observance of traffic laws, and a pleasantly conspicuous absence of human enforcers at every intersection are all present. Though far superior to our own city, it’s far from perfect. I sincerely don’t know why there seem to be so many hotheads in the Philippines on the road, and I wish Metro Manila was like this.

With strict noise regulations, straight-piped motorcycles and jeepneys could be a thing of the past. PHOTO BY FRANK SCHUENGEL

Sounds? What sound? Bangkok has remarkably quiet roads for a busy Asian megacity. There aren’t any jeepneys with exhausts shaped like Jericho trumpets, no buses making a loud announcement of their arrival, and very few people honking their horns.

Bangkok’s roads have a soundtrack that is positively serene in comparison to Metro Manila’s insane cacophony. This is so quiet that you could put it on a CD and market it as a meditation track. LGUs in the Philippines, listen up!

Chinese EVs seem to be popular in Bangkok. PHOTO BY FRANK SCHUENGEL

EV usage is growing. Advertisements for electric vehicles can be found everywhere you look. Thailand is currently being heavily targeted by mostly Chinese brands. Though they aren’t very common yet, EVs are still visible on the road.

It appears that BYD is well-represented here. Even though it’s just as hot and muggy as it is at home, the air feels much cleaner here. That is most likely due to both functional and appropriately enforced vehicle emission regulations as well as EVs.

Finally, a country that actually uses pickups as intended instead of as an extension of one's ego. PHOTOS BY FRANK SCHUENGEL

They play pickup like pros. You’ll see a lot of these cars on our roads as well. But Thai drivers are in a different league than Filipinos when it comes to pickup trucks.

It’s amazing how people here make the most out of these vehicles by putting enormous cargo bays on the back of these dependable cars. With a Hilux, who needs a heavy-duty truck?

This is one thing that we can look forward to—if the subway is built properly. PHOTO BY FRANK SCHUENGEL

An excellent subway has a profound impact. Bangkok traffic is still a problem; rush hour there can resemble our shores’ never-ending metal avalanche. However, you can at least take the subway in the capital of Thailand to get away from it.

It’s a cheap, clean, modern subway. Additionally, data coverage and a full mobile signal are included. I am eagerly awaiting the launch of Metro Manila’s underground train in the coming years, and I sincerely hope that the designers will learn from and incorporate the best features from other metro systems across the world.

Overground adjustments will also be needed for Metro Manila. As I discovered in Bangkok and numerous other cities, a subway is only completely functional if people can walk to it with ease. Sadly, sidewalks are frequently overlooked in the Philippines; hopefully, this project will address this.

It may be more tourist-oriented, but boats are still additional forms of transportation. PHOTO BY FRANK SCHUENGEL

Among them are boats. Even though the majority of the boats speeding up and down Bangkok’s Chao Phraya River are packed with tourists, they nevertheless contribute significantly to the city’s transportation system. One that would be simple to greatly expand throughout Metro Manila.

By now, anything that gets people off the road and out of cars has to be good, and for both commuters and tourists, a breezy ferry ride up and down the Pasig River might be just the thing.

The Philippines could learn so much from Bangkok. PHOTO BY FRANK SCHUENGEL

Unfortunately, it doesn’t appear to be very popular. Thankfully, Metro Manila is now moving in the right direction and adding more and more bike lanes. However, it appears that there aren’t many two-wheelers driven by people in Bangkok, and there aren’t many designated bike lanes. Perhaps there is less of a need to move around by using physical strength because the metro system is so expansive and contemporary.

In summary, Bangkok evokes visions of the metropolis that Metro Manila might become if it were to finally get its act together.

References
visor.ph

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Asia Noise News Noise-th

Agencies are instructed to handle noise from the extended pub opening hours

Since December 15, when the Surat Thani province’s law permitting pubs, bars, and entertainment venues in specific areas of Bangkok, Phuket, Chonburi, Chiang Mai, and Koh Samui to stay open until 4am went into effect, the public has filed 5,785 complaints regarding noise.

As per a Government House source, the Interior Ministry has been directed by the cabinet to devise strategies to address these disturbances and submit an update to the Office of the Prime Minister on a quarterly basis.

Although national hotel regulations allow services within hotels to run until 4am, any entertainment venues that stay open past that time must strictly abide by the law, particularly the Alcoholic Beverage Control Act and the Entertainment Places Act.

It is against the law to sell alcoholic beverages to anyone under the age of twenty-one or to someone who passes out after drinking.

In fiscal year 2023, 57,399 complaints were filed, down from 67,919 in fiscal year 2022, according to the Office of the Prime Minister.

The majority of complaints were about noisy restaurants, entertainment centers, and festival gatherings. 5,607 out of the 5,785 cases have been settled.

Other complaints from the public included issues with electricity at 3,575. These included requests for more lights to be installed in pedestrian areas, a reduction in electricity bills, and an evaluation of the methodology used to calculate electricity.

With 2,355 cases, political complaints ranked third and included complaints about the general election, the campaign, the formation of the government, and the platforms of political parties.

References

www.nationthailand.com

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Environment Noise-th

Pattaya police crack down on noise nuisance and street racing

Thailand’s Pattaya – In response to the urgent problem of street racing and noise disturbance brought on by Arab tourists in the Soi 18 and Pattaya Second Road areas, Pattaya police launched a comprehensive crackdown on reckless driving and disorderly behavior on August 5.

As a result of their loud vehicles and disruptive behavior, large groups of Arab tourists have started congregating in South Pattaya’s notorious Soi 18 neighborhood. Both locals and visitors in the area have experienced discomfort as a result of the constant engine revving and the ensuing cacophony of noise.

The traffic police have already taken action to reduce erratic driving and noise pollution. They have intensified their efforts by sending more officers to strategic locations where these Arab groups are known to congregate and engage in street racing, though, in response to recent unruly incidents.

The traffic department has consistently enforced traffic discipline measures, according to Pol. Lt. Col. Arut Sapanont, head of the Pattaya City Traffic Police Division. However, given the unique difficulties presented by the Arab groups, they have stepped up their presence in key areas to discourage and capture those who engage in street racing and causing disturbances.

“Offenders caught participating in illegal street racing and causing noise disturbances will face severe penalties,” police lieutenant colonel Arut warned. To address the violations, the traffic police will issue two separate summonses. The first summons targets motorists who are observed operating vehicles without valid licenses, without helmets, or with unauthorized modifications, such as loud exhaust pipes.

Those rental companies connected to these unlawful activities will receive a second summons. They run the risk of having their vehicles impounded and a 2,000 Baht fine. Police confiscated 10 motorcycles during the crackdown, including two that had illegal modifications.

References

https://www.pattayamail.com

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Asia Noise News Building Accoustics Building Acoustics Environment Noise and Vibration Product News Noise-th Uncategorized Vibration

Regulations, guidelines, and standards regarding environmental noise in Indonesia

With all the development, industrial activities and community activities in Indonesia, noise has become one of the problems that arises in some places in Indonesia. Indonesia already has some regulations, guidelines, and standards to safeguard the noise levels. This is important mainly to support a healthy environment for the people, and also to improve budgeting certainty of projects that will produce noise during their operations.

The following are the regulations, standards and guidelines related with environmental noise in Indonesia.

Environmental Noise Regulations

Regulations regarding environmental noise generally can be categorized into two types which are emission regulation and immission regulation. Emission regulations regulate how much noise can a noise source produces noise, while immission regulation regulates how much noise can a receiver or area receives noise.

Examples of noise emission regulations in Indonesia are:

  • Decree of Minister of Environment and Forestry No. 56 year 2019 (P.56/MENLHK/SETJEN/KUM.1/10/2019) regarding noise limits of new types of motorized vehicles and in production M category, N category, and L category.
  • Decree of Minister of Transportation of Republic of Indonesia No. PM 62, year 2021 regarding civil aviation safety section 36 regarding noise standard dan type certification and aircraft airworthiness

The two ministerial decrees above regulate how much noise can be produced by vehicles that are used on road and aircraft that can operate within Indonesian territory.

The regulation that regulates environmental noise level at the receiver is:

  • Decree of Minister of Environment No. 48 year 1996 about noise level limits

 

The decree states the noise limits that are allowed for the receiver according to its function – for example for residential area, the noise limit is 55 dBA and for industrial area 70 dBA. More details on the following link: https://www.konsultasi-akustik.com/en/environmental-noise-measurement/

 

Beside the regulations above, there are other requirement such as one written on Government Regulation (PP) No. 36 year 2005 regarding implementation rules of the Law No. 28 year 2002 regarding buildings. One of the points require noise reduction means for toll roads in residential area or existing city centers.

 

Guidelines regarding Environmental Noise

 

Beside the regulation, there are some technical guidelines that are written by Ministry of Public Works as follows:

  • Technical guidelines Ditjen Bina Marga No. 36 year 1999: Noise barrier planning guidelines
    In these guidelines, criteria to categorize area as safe, moderate and high risk are given. Moreover, the guidelines also state measurement techniques for measurement beside road and common type, shape and material of noise barriers.
  • Construction and building guidelines Pd T-10-2004-B: Road traffic noise prediction.

These guidelines adopt calculations from Calculation of Road Traffic Noise (CoRTN, UK, 1998) which contain noise calculation method based on traffic volume and speed. There are also corrections for heavy vehicle percentage, speed, gradient and road surface. From this calculation, propagation to receiver can be calculated considering distance, screening, reflection and angle of view.

  • Construction and building guidelines Pd T-16-2005-B: Mitigation of road traffic noise

The guidelines lay out methods to mitigate noise from traffic which is based on measurement (which are written on Permen LH No. 48 year 1996 and guidelines No.36 year 1999 above) and can also be based on predictions (Following construction and building guidelines Pd T-10-2004-B)

 

Environmental Noise Standards

 

Beside the regulations and guidelines, there are Indonesian National Standard (SNI) document that are written by National Standardization Body (BSN) that are related to environmental noise:

  • SNI 19-6878-2002 – Road traffic noise test L10 and Leq
    This standard contains test method which state testing procedure and data processing steps to calculate LA to L10 and Leq
  • SNI 8427:2017 – Pengukuran tingkat kebisingan lingkungan
    This standard contains measurement method that is similar to Kepmen LH No.48 year 1996 which is to measure noise samples for 10 minutes across 24 hours period. Noise levels then can be calculated based on its time slice which are Ls (daytime noise), Lm (nighttime noise), and Lsm (day-night noise, with 5 dB penalty for nighttime).
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What you need to know about Room Acoustics

In the Southeast Asia region especially, acoustic properties of residential buildings are often neglected by designers, developers, contractors, and even home buyers. Noises from both internal and external environments affects occupants’ daily lives, causing nuisance which can strongly deteriorate one’s living quality as a long-term effect. In this article, we will investigate building/room acoustics, and the actions that can be undertaken to improve the acoustical environment inside a building.

Room acoustics

In general, the acoustics of rooms can be divided into two groups: low frequency and high frequency. Sound in rooms can be highly affected by the reflective properties of the surfaces in the room. This is because multiple reflections may occur if the room surfaces are highly reflective, which then leads to a reverberant field in addition to the direct field from the source especially at higher frequency range. Therefore, at any point in the room, the overall sound pressure level is influenced by the energy contained in both the direct and reverberant fields (Crocker, 2007).

Sound transmissions in buildings

Sound can be transmitted within a building by transmitting through air in the spaces bounded by walls or roofs/ceilings, known as airborne transmission. Another way would be through structural transmission through the structural assemblies of the building, or impacts.

Airborne sound originates from a source that radiates sound waves into the air, which would then impinge on the building surfaces. A good example of airborne sound will be speech, or music from a television or loudspeaker. On the other hand, impact sound is being generated when an object strikes the surface of a building. The commonly heard impact sounds that we can hear in buildings are footsteps, furniture-dragging sounds, cleaning, and other equipment that is used directly on the floor surfaces. To overcome these noises, good sound isolation should be considered for all the possible paths for sound and the junctions between walls and floors, not just at the direct path through common wall or floor.

Sound insulation – airborne and impact

It is imperative to consider the control of airborne and impact sound transmission through the building elements like walls, ceilings, or floors, as stated above. In this case, sound insulation methods will be crucial. Different methods can be implemented for airborne, impact and flanking sounds (Crocker, 2007).

For airborne sound, insulation can be applied at any building element. This is because when sound hits on a surface, a very small fraction of the incident energy will be radiated from the other side. The sound transmission loss (TL), which is the ratio of the incident sound energy relative to the transmitted sound energy is typically measured. TL can be expressed in decibels (dB), and it is sometimes known as sound reduction index (R) in European and ISO standards. The elements to be used in buildings for sound insulation are measured in accordance with standards, where the commonly seen method would be the two-room method. A test specimen would be mounted between a reverberant source room, and a receiver room such that the only significant path for sound to transmit through is the specimen, and other possible transmission paths would be suppressed. As such, it will be useful to determine the TL of the building elements/materials so that one can estimate the airborne sound insulation performance inside the building space.

As for impact sound which typically radiates from a floor into rooms below or horizontally, insulation can be done via floor coverings or floor slabs. This is because the applications of these items can reduce the impact sound pressure levels that travels into the receiver room. The typical methods of insulation are adding soft floor coverings on concrete slab, increasing the thickness of concrete floors, or implementing floating floors.

Single number ratings

To know the acoustic information of an insulation element, the standard method would be to refer to the single number ratings of that element. These ratings would be assigned to building materials based on their sound transmission spectra by the means of reference curves or weighted summation procedures.

The most used single-number rating for airborne sound insulation is the Sound Transmission Class (STC), which is in accordance with the American Society for Testing and Materials (ASTM) E413. There is another equivalent number called the Weighted Sound Reduction Index (Rw), which is based on the International Organization for Standardization (ISO) standard ISO 717.

The figure above shows an example of STC contour fitted to a concrete slab’s data. The differences between data points below the contour line and the value of contour are called the “deficiencies”. According to ASTM E413, the sum of deficiency should not be greater than 32 dB, and each individual deficiency should not exceed 8 dB (also known as the 8-dB rule). The reference contour for ASTM covers the frequency range from 125 Hz to 4000 Hz. The Rw contour from the ISO 717 has the same shape, except that it covers a broader frequency range of 100 Hz to 3150 Hz. Also, there is no 8-dB rule in ISO 717. Comparing both standards, the numbers from both ratings are usually close. However, the weighted summation method developed in ISO 717 accounts for the higher importance of low frequencies in traffic noise and modern music systems. As such, this method allows corrections/spectrum adaptation terms to be produced that can be used in conjunction with the Rw rating.

As for impact sound insulation, the sound pressure levels are often collected using a standard tapping machine and normalised, which will then be used with a reference curve to calculate its rating, typically the Impact Insulation Class (IIC), or the weighted index Ln,w. In fact, these ratings are commonly used in building codes. Again, the rating curves are identical in each standard, but there are some differences among them still. For instance, the ASTM IIC method does not allow any unfavourable deviation to exceed 8 dB. An increasing IIC rating would indicate that the impact sound insulation improves. Conversely, the Ln,w rating would decrease as the impact sound insulation gets better. We can take the relationship between both ratings as follow (assuming that the 8-dB rule is not invoked):

However, there is debate regarding the usefulness of ISO tapping machine data obtained on different types of floors. Therefore, the latest version of ISO 717-2 proposed the use of C1, a spectrum adaptation term to consider low-frequency noise that is normally generated below a lightweight joist floor.  is the unweighted sum of energy in the one-third octave bands (50 or 100 Hz – 2500 Hz) minus 15 dB. According to the standard, this rating is expected to have a better correlation with the subjective evaluation of noise coming below floors, especially for low frequency ones.

The single rating numbers mentioned above are all useful when it comes to determining the level of acoustic insulation a material can provide. With the explanation above about room acoustics and the insulation measures that can be implemented, it will give a better idea on how one should tackle and handle the room acoustics in a building.

References

Crocker, M. J. (2007). Chapter 103: Room Acoustics. In C. H. Hansen, & M. J. Crocker (Ed.), Handbook of Noise and Vibration Control (pp. 1240-1246). Adelaide, South Australia, Australia: John Wiley & Sons, Inc. doi:ISBN 978-0-471-39599-7

Crocker, M. J. (2007). Chapter 105: Sound Insulation—Airborne and Impact. In A. C. Warnock, & M. J. Crocker (Ed.), Handbook of Noise and Vibration Control (pp. 1257-1266). Ottawa, Ontario, Canada: John Wiley & Sons, Inc. doi:ISBN 978-0-471-39599-7

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Acoustic of Small Studio

Studio Acoustic

Small studios are now widely used in the recording industry due to their high feasibility and them being economically friendly, which allows those working in the recording/music industry to be able to work remotely without needing to travel to big studios that much. With a good implementation of acoustic treatments, music recorded in small studios can still be high in sound quality, sometimes even suitable for commercial release.

So, what makes a recording studio good?

In today’s article, we will look into the acoustics of small recording studios, where music is performed as recorded (Everest & Pohlmann, 2015).

Ambient conditions

A quiet environment is a must for a studio to be useful, which is sometimes quite hard to achieve. First, noisy sites should definitely be avoided as many noise and vibration problems will not arise by just choosing a site in a quiet location for your studio. Avoid places near loud areas like train tracks, busy road intersections, or even an airport. The ultimate idea is to reduce the external noise spectrum, then keep the background noise within the criteria goal by implementing sound insulations in the building. However, the construction costs of effective insulation elements like floating floors or special acoustically treated walls/windows/doors may cost greatly. Hence, the best way, that is more cost-effective, will be to choose a quiet site in the first place, rather than isolating a studio located at a noisy place.

The HVAC system, which includes heating, ventilating and air-conditioning systems should be designed such that the acoustics meet the required noise criteria goals. The noise and vibration coming from motors, fans ducts diffusers etc. should be brought to the minimum so that low ambient noise levels can be achieved.

Noise

Similar to any other quiet rooms, a small studio needs to comply with the acoustical isolation rules and standards. It is important to construct the building elements with high transmission loss and decoupled from external noise and vibration sources to ensure that the ambient noise levels are low enough for good recording quality. Not only that, but these constructions will also act as an isolation that prevents loud noise (music) levels in the studio from affecting the neighbouring spaces.

Studio acoustical characteristics

Inside a studio, the types of sound present, and may be picked up by microphones, are the direct and indirect sounds. Direct sound is basically the sound coming from the source (before it hits a surface). Indirect sound follows right after the direct, caused by various non-free field effects characteristic of an enclosed area. In short, everything that is not direct sound is considered as indirect or reflected sound.

It is known that the sound pressure level in an enclosed space will vary according to the distance from a source, while also being affected by the absorbency of the room or space. If all the surfaces in a room are fully reflective, it means that the room is fully reverberant (like a reverberation chamber), therefore the sound pressure level would be the same (as of the sound from the source) everywhere in the room as no sound energy is absorbed. It can also be assumed that there is relatively no direct sound since most of the sounds are reflected, hence indirect. Another component that causes indirect sound comes from the resonances in a room, which is also the result of reflected sound.

Indirect sound also depends on the materials used for room construction (e.g., doors, walls, windows, floors, ceiling etc). These elements can also experience the excitation by the vibration of sound from the source, hence able to decay at their own rate when the excitation is removed.

Reverberation Time

The composite effect of all the indirect sound types is reverberation. Many would say that reverberation time is an indicator of a room’s acoustical quality, but in reality, measuring reverberation time does not directly reveal the nature of the reverberation individual components, giving a small weakness of reverberation time being the indicator. Therefore, reverberation time is often not the only indicator of acoustical conditions.

Reverberation time is, by definition, the measure of decay rate, and is usually known as T60. For example, a T60 of 1 second represents that a decay of 60 dB takes 1 second to finish. Some may say that it is inaccurate to apply the reverberation time concept to small rooms, as a genuine reverberant field may not exist in small spaces. However, it is still practical to utilize the Sabine equation (for reverberation) in small-room design to make estimations on the absorption requirements at different frequencies, provided that limitations of the process are taken into account during the estimation.

It is not good to have it being too long or too short. This is because for a room with reverberation time that is too long, speech syllables and music phrases will be masked hence causing a worsening speech intelligibility and music quality. Conversely, if the reverberation time is too short, speech and music will lose character therefore suffer in quality, whereby music will typically suffer even more. Despite that, there is no specific optimal value for reverberation time that can be applied for any rooms, because too many factors are also involved besides reverberation. Things like the types of sound sources (female/male voice, speed of speech, types of language etc) will all affect the room’s acoustic outcome. However, for practical reasons, there are approximations available for acousticians to refer to, where certain amount of compromise has been implemented to make it usable in many types of recording applications.

Diffusion
A high diffusion room give a feeling of spaciousness due to the spatial multiplicity of room reflections, and it is also a good solution to control resonances effects. To create a significant diffusing effect, the implementation of splaying walls and geometrical protuberances works well. Another way will be to distribute absorbing materials in the room, which also increases the absorbing efficiency of the room apart from diffusion. Typically, modular diffraction grating diffusing elements (e.g. 2- x 4-ft units) can provide diffusion and broadband absorption, and can be easily installed in small studios. Still, there will not be much diffusion in a studio room, in practice.


Examples of acoustic treatment
So, what are the acoustic treatment elements that you can use to improve your studio? These items below can be considered (Studio, 2021):
1. Bass Traps
This is one of the most important tools to have in a studio. Bass traps are normally used to absorb low frequencies, also known as bass frequencies, but in fact they are actually broadband absorbers. This means that they are also good at absorbing mid to high frequencies too.

2. Acoustic Panels
Acoustic panels work similarly like bass traps, but rather ineffective at absorbing the bass frequencies. One thing good about acoustic panels as compared to bass traps is that since they are much thinner, they offer more surface area with less material. Therefore, acoustic panels are capable of providing larger wall coverage with less cost as compared to bass traps.

3. Diffusers
Diffusers may not be as effective as compared to bass traps and acoustic panels if used in small studios. So, this really depends on users, whether they find diffusers useful for their application.
Now, where should the acoustic treatment products be placed at?
There are three key areas of the room to be defined in this case:
– Trihedral corners
– Dihedral corners
– Walls
The priority for coverage goes from trihedral corners, dihedral corners to the walls. This is because acoustic treatments should ideally be placed at areas which have the greatest impact. At trihedral corners, for example, three sets of parallel walls converge, hence if there is absorption material located here, it catches the room modes from all three dimensions, giving three times the initial effectiveness. Same concept goes for dihedral corners and walls, but with two dimensions and one dimension respectively.

 

References
Everest, F. A., & Pohlmann, K. C. (2015). Acoustics of Small Recording Studios. In F. A. Everest, & K. C. Pohlmann, Master Handbook of Acoustics (6th Edition ed.). McGraw-Hill Education – Access Engineering. doi:ISBN: 9780071841047
Studio, E.-H. R. (2021). CHAPTER 3: The Ultimate Guide to Acoustic Treatment for Home Studios. Retrieved from E-Home Recording Studio: https://ehomerecordingstudio.com/acoustic-treatment-101/

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Noise Barriers

Noise barriers are designed to resist the sound waves in the propagation path from source to receiver. In general, the closer the barrier is to the source the more effective it becomes. For simple plane barriers the height and length are the most important factors determining the degree of screening achieved and simple design rules have been developed to determine the reduction in overall noise levels.  These are based on the path difference between the direct path from source to receiver through the barrier and the shortest path passing over the top of the barrier. The greater this path difference the greater the screening. The shadow zone of the barrier is the region where the receiver cannot see the source and here the greatest reductions in noise levels are recorded. Some sound will always be diffracted over the top and around the edges of the barrier into the shadow zone so it is not possible to eliminate all noise from the source. However, typical barriers of a few metres high can achieve a worthwhile noise reduction of the order of 10 dB(A). This corresponds to halving the subjective loudness of the sound.

 

Figure (a)

Figure (b)

For more complex barriers simple methods are not appropriate and numerical methods such as the Boundary Element Method (BEM) have been used to produce accurate solutions.

Many different types of barrier have been installed using a wide variety of materials including wood, steel, aluminium, concrete and acrylic sheeting. Some of these designs have absorptive facings on the traffic side which reduce reflected sound. Barriers over 8 m in height have been used for some applications and novel capped barriers and angled barriers have been tested.

Barriers that may offer improved performance over simple plane barriers can be grouped under the following broad headings.

The above fig (a) shows the Main pathway of the sound propagation from the source to the barrier’s edge for sound walls with or without source-side absorption. Fig (b) shows Absorption material construction.

If smaller vehicles passing by the barrier, the reflection off the vehicle it does not play much of a role. Multiple reflections can only occur if noise barriers are built along both sides of the highway or train tracks.

In the case of large noise emitters, the implementation of source-side absorbent noise barriers can prevent the so-called zigzag effect

  1. Absorptive barriers—that is, barriers incorporating elements on the traffic face that absorb a significant proportion of incident sound and hence reduce reflected sound which could contribute to overall noise levels in the vicinity.
  2. Angled barriers—that is, barriers that are tilted away or have contoured surfaces angled to disperse the noise, the aim being to prevent significant sound reflections into the area where screening is required.

 

ABSORPTIVE BARRIERS

Where a plane vertical barrier is erected on one side of the road then sound reflections to the opposite side take place as illustrated in fig 1(a). In addition, reflections between vehicles and the barrier may lead to loss of screening performance as shown in fig (b). Where plane vertical barriers exist on both sides of the road, as shown in fig(c), they are normally parallel to each other and, in this situation, sound is reflected back and forth between the barriers again leading to a loss in performance. Absorbing panels located on the sides of the barriers facing the traffic can reduce this reflected contribution by absorbing the sound energy from the incident wave.

ANGLED BARRIERS

An alternative to using sound absorptive barriers is to angle the barrier or parts of the barrier away from the road such that the reflected wave from the traffic face of the barrier is deflected upwards, so reducing the contribution to noise at receptor positions relatively close to the ground. The performance of such barriers has been measured at full scale at TRL’s unique Noise Barrier Test Facility (NBTF).  The noise source used consisted of an 800 W speaker that can be positioned in front of the test barrier on a specially laid strip of hot rolled asphalt, thereby representing the traffic source on motorways and all-purpose dual carriageway roads. Microphones can be positioned to measure the noise level in the shadow zone of the test barrier at any point on a wide flat grassland area free of reflecting objects. To measure the acoustic performance of the barrier, recorded noise in a broad frequency range is broadcast and noise levels are measured at standard locations behind the barrier. Corrections can be made for variations in speaker output and wind speed and direction. In this way the screening performance of the barriers for a typical traffic noise source can be evaluated.

The above fig shows angled noise barrier.

Source : Various books and research journal

Categories
Asia Noise News Building Accoustics Building Acoustics Environment Home Industrial Noise and Vibration Product News Noise-th Vibration Virtual Data Room

The power of trees can reduce noise.

The way most workers need to complete tasks have significantly changed the way companies use their spaces. Quiet spaces are needed for deep, focused work. Technology enabled meeting rooms and collaboration spaces are used for productive meetings. Ideally, an office is designed in such a way that it enables team members to do their best work.

Unfortunately, it can be difficult to make sure a design includes all these aspects. As a result, designers and architects still often have to leave space for cubicles and open office spaces, a big contributing factor to general noise levels.

Did you know? Planting trees in your home or office not only helps to cool the internal temperature, increase the oxygen in the air give a feeling of freshness, and help relax only. But plants can also HELP ABSORB NOISE!

One creative way to both combat office noise and bring biophilic elements to a design is to incorporate plants and greenery into a space. Studies have shown that both plants and living green walls are an effective way to absorb sound and noise pollution.

Beyond their sound absorbing qualities, plants and biophilic elements can help to improve a worker’s overall well-being. Access to natural elements like greenery, natural light, and organic textures have been found to both improve employee productivity and reduce absenteeism. Plants have been found to be a mood booster and a stress reliever for team members, which can in turn, help to improve an employer’s bottom line.

Do Plants Help to Absorb Sound?

There is quite a bit of research on the subject, but the short answer is yes. The flexible and porous nature of indoor house plants acts as natural sound reducers. There are three ways that house plants can reduce the sound in your home or office: deflection, absorption, and refraction.

Most people do not understand the sound absorption benefits of houseplants. However, they really do help with absorption sound.

How Plants Reduce Indoor Noise Levels?

As mentioned above, plants reduce noise levels through three different methods: deflection, absorption, and refraction.

  • Deflection – Sound waves tend to bounce around off hard surfaces. That is where all that added noise comes from. Walls are rigid and will amplify sound, while plants are flexible and help to deaden the sound by breaking up the sound waves into other forms of energy.
  • Absorption – Plants are great at absorbing sound because of the leaves, branches, and wood. Wood is a great sound absorber. Have you ever walked through a forest and been amazed at the silence? That is because the trees are absorption all the ambient noise.
  • Refraction – Refraction is taking away the echoes of the sound bouncing off the hard surfaces. Plants will help to refract this noise and eliminate the echoes which are responsible for much of the added noise in your home or office.

The indoor plants that work best at absorbing sound such as:

  • Ferns: have a lot of surface space to help reduce sound. Their wide leaves spread out and cover quite a bit of area.
  • Baby’s Tears: Baby’s Tears are a dense plant that looks almost like moss. The plant has a way of draping itself over the pot and makes a great sound reducer when elevated off the ground.
  • The Peace Lily: The Peace Lily can absorb some of the sounds with their leaves and do a great job of bouncing the sound to the other plants and is a great sound absorbing plant you can put in your home. Their true noise absorbing properties are in their thick, broad leaves.
  • The Rubber Plant: The beauty of this plant is just how big it can get. Rubber plants cover a large surface area which only serves to enhance their sound absorbing properties.
  • Fiddle Leaf Fig: The fiddle leaf fig is another plant with broad, thick leaves. They can grow tall, and the cupped shape to the leaves make for an effective sound absorber.

Reference :

พลังจากต้นไม้ ลดมลพิษทางเสียง

https://bettersoundproofing.com/best-sound-absorbing-indoor-plants/

The Top Sound Absorbing Plants For The Workplace

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