Vertical and Adjacent Crosstalk of Induction Loop Systems in NUS COM4

The NUS School of Computing is proud to introduce their new facility, the 5-storey COM4 building, where student of NUS’ School of Computing can utilise for various uses from discussions, to learning and teaching labs. The School of Computing has decided to cater their facility to be as inclusive as possible which has accessibility, including Hearing Enhancement Systems to be implement within the rooms throughout the building.

 

Hearing Enhancement Systems or Induction loop systems have become an integral part of ensuring accessibility and inclusivity for individuals with hearing impairments. These systems use magnetic fields to transmit sound directly to hearing aids or cochlear implants, enabling users to hear clearly in public spaces, such as theatres, lecture halls, and conference rooms. However, to ensure optimal performance, it is crucial to understand two important concepts related to induction loop systems: vertical and adjacent crosstalk or Overspill. In this article, we will delve into these concepts and explore their significance in creating a seamless listening experience for all.

 

What is Vertical Overspill?

 

Vertical overspill refers to the dispersion of the magnetic field generated by an induction loop system above and below the intended coverage area. It occurs when the magnetic field extends beyond the desired boundaries, leading to signal leakage and potential interference with other induction loop systems that are located above and below. Vertical overspill can cause problems in multi-story buildings or venues with multiple floors or rooms situated above and below each other. To mitigate vertical overspill, the installation of induction loop systems should involve careful consideration of the venue's structure and acoustics and in this case, the induction loops can be found above the false ceiling.
 

 

Factors affecting Vertical Overspill

 

Factors such as the height of the loop, the presence of metal structures or obstacles, and the layout of adjacent rooms or floors can impact the extent of vertical overspill. By using appropriate loop designs, like a low spill multiloop, it is possible to limit the magnetic field's vertical dispersion, focusing the signal within the desired listening area and minimizing interference with other spaces.

 

Challenges in installing Induction Loops in Ceilings

 

The standard location in installing Induction Loops would be either on or in the floor. However, there are special circumstances in which resorting to installations of induction loops in the ceilings would be a requirement to overcome the vertical overspilling of signals between rooms that are above and below each other.

 

The challenges faced when installing of ceiling loops are;

  1. Height of ceiling – during installation and future troubleshooting if required, the induction loops will be at heights of at least 2.5 meters which requires ladder access.
  2. Access and Space Constraints – Dependent on the overall height of the room, access to ceilings would require the usage of ladders and following that, when working with false ceilings, the presence of the aluminum grids reduce the accessibility and space that installers have.
  3. Material of Ceiling – metal grids of false ceilings can have an impact to the overall performance of the induction loop due to Metal Loss, hence proper planning is required for an effective effect.
  4. Presence of other services in ceilings – other services will also be housed in the space above the false ceiling, hence, proper coordination between contractors is crucial to ensure that there is sufficient space to install the induction loop systems.

 

Achieving IEC 60188-4 Compliance for Induction Loops in Ceilings

 

In NUS COM4’s context, the induction loops are installed at 3.3 meters from the floor which is quite a distance that requires a higher rating loop driver to be able to generate the signal down to the listening height which is at seated position. On top of that, the performance of the induction loop is further hindered by Metal Loss that is due to the aluminium grids that hold up the ceiling boards.

 

To overcome these challenges, the highest rated amplifiers were proposed to check the requirements to comply to the IEC 60118-4 standards for induction loops that were installed in the ceilings.

 

What is Adjacent Overspill?

 

Adjacent overspill refers to the spreading of the magnetic field beyond the intended coverage area horizontally. It occurs when the magnetic field extends into neighbouring areas, potentially causing overlapping signals and reducing clarity. Adjacent overspill is particularly relevant in environments where multiple induction loop systems are installed side by side or in close proximity.

 

To address adjacent overspill, proper planning and design are crucial. The spacing between adjacent induction loop systems should be carefully determined to avoid interference. Additionally, advanced signal processing techniques can be employed to reduce crosstalk and enhance the separation of adjacent systems.

 

Importance of Minimizing Overspill

 

Minimizing both vertical and adjacent overspill is vital to ensure a high-quality listening experience for individuals using hearing aids or cochlear implants. Excessive overspill can lead to sound distortion, reduced speech intelligibility, and confusion, thereby defeating the purpose of installing an induction loop system. By understanding and addressing these issues during the system's design and installation phase, venue owners and specialists can maximize the system's effectiveness and provide equal access to audio information for all individuals.

 

Conclusion

 

Vertical and adjacent overspill are crucial considerations when implementing induction loop systems. To achieve optimal performance and user satisfaction, it is essential to carefully design and install the system while taking into account factors such as building structure, room layout, and neighbouring systems. By minimizing overspill through appropriate loop design, spacing, and signal processing techniques, venues can provide seamless access to audio information for individuals with hearing impairments, promoting inclusivity and enhancing the overall experience for all attendees.

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Shaw Theatres Balestier

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Overspilling Effect: Enhancing Accessibility for the Hearing Impaired in Shaw Theatres Balestier

AWWA School @ Bedok, Singapore

In today's world, accessibility and inclusivity are paramount considerations across various domains, including public spaces, performances, and events. One crucial aspect of inclusivity involves ensuring that individuals with hearing impairments can fully participate and enjoy these experiences.

 

To address this need, induction loop systems have emerged as powerful tools, providing direct sound transmission to hearing aids and cochlear implants, bypassing background noise and delivering clear audio to the listener.

 

While induction loops have revolutionised accessibility, a particular challenge arises when these systems are installed in adjacent rooms or spaces. This challenge is known as the overspilling effect, where the magnetic field generated by an induction loop extends beyond its intended coverage area, potentially leading to audio leakage and compromised listening experiences. Understanding and mitigating the overspilling effect is vital to creating optimal audio environments for individuals with hearing impairments.

 

This study delves into the complexities of the overspilling effect in induction loop systems. We explore the factors influencing its occurrence, such as proximity, loop design, and loop amplification. Furthermore, we uncover strategies professionals employ to minimise the impact of overspilling, ensuring that individuals with hearing impairments can enjoy clear and private audio experiences in adjacent rooms or spaces.

 

By shedding light on the overspilling effect and sharing insights into its mitigation, we aim to foster greater awareness and understanding of this challenge. Join us on this journey as we navigate the intricacies of induction loop systems, and discover how professionals are working towards creating inclusive environments that prioritise accessibility for all individuals, regardless of their hearing abilities.

 

Renovating Shaw Theatres Balestier

 

Image from Shaw Theatres Balestier

 

Shaw Theatres Balestier opened its doors on 30th March 2023 after having undergone renovations for a design revamp since August 2019. It houses 11 theatre halls, making it the cinema with the most halls in a single location in Singapore. Six of the 11 halls are regular, while 4 Premium Lumiere Halls are located on the same level, and 1 Dreamers Hall is on one lower level.

 

Image from Shaw Theatres Balestier

 

Adjacent Cinema Halls on The Same Level

Halls 1 through 6 and Lumiere Halls 1 through 4 are located on the same level and are adjacent. Implementing the Induction Loop Systems in every hall poses a challenge due to Signal Interference or the Overspilling Effect.

 

Induction or hearing loops are vital in enhancing

Accessibility for individuals with hearing impairments. These systems utilise electromagnetic fields to transmit sound directly to hearing aids and cochlear implants, bypassing background noise and delivering clear audio to the listener.

 

While induction loops are commonly used in various public spaces, such as theatres, lecture halls, and places of worship, their effectiveness can be impacted by the overspilling effect when installed in adjacent rooms.

 

Understanding Overspilling

Overspilling occurs when the magnetic field generated by an induction loop system extends beyond its intended coverage area. This spillage can cause audio leakage from its intended location, potentially resulting in a breach of privacy or a degraded listening experience for individuals using hearing aids or cochlear implants equipped with telecoils (T-coils). In scenarios where multiple induction loops are installed in adjacent rooms or spaces, the overspilling effect can pose a significant challenge.

 

Factors Influencing the Overspilling Effect

 

  1. Proximity: The distance between induction loop systems in neighbouring rooms affects the extent of magnetic field overlap. The closer the loops are, the greater the likelihood of overspilling.
  2. Loop Design: The physical layout and design of the induction loops, including their shape, size, and orientation, can influence the reach of the magnetic field. Irregularly shaped rooms or areas with architectural barriers may worsen the overspilling effect.
  3. Loop Amplification: The amplification level of the induction loop system impacts the strength of the magnetic field and, consequently, the overspilling effect. Higher amplification settings may lead to a more significant overspill.

 

Ways to Minimise the Overspilling Effect

While eliminating the overspilling effect may be challenging, there are several strategies that can help minimise its impact and maintain optimal accessibility.

 

  1. Proper Loop Installation: Professional installation by specialists is crucial to ensure that induction loops are correctly positioned and calibrated. This includes considering the location and orientation of adjacent rooms to minimise overspill.
  2. Loop Design Considerations: Architects and designers should collaborate with induction loop specialists during the planning phase of building projects to optimise loop design. This involves evaluating the physical characteristics of adjacent rooms and incorporating appropriate loop configurations to minimise overspill.
  3. Loop Amplification Adjustment: Properly adjust the amplification level of the induction loop system to minimise overspill. Fine-tuning the amplification settings ensures the magnetic field is strong enough to provide sufficient coverage within the intended space without unnecessarily extending into adjacent areas.

 

As technology advances, new solutions for overcoming the overspilling effect are being developed. For example, some companies are developing induction loop systems that use directional microphones to direct the sound waves in a specific direction. This can help to reduce the amount of overspilling that occurs in adjacent rooms or spaces.

 

How We Overcame the Overspilling Effect Between Rooms

 

Loop Type Used: Low Spill Multiloop

 

To contain the signal from spilling not far from the loop boundary. Usually used to prevent the magnetic field generated by the loop from causing interference with the adjacent room.

 

To overcome the Overspilling Effect, we utilised a Low Spill Multiloop with a C7-2 Amplifier in tandem for every theatre hall to allow us to make precise minute adjustments to meet the IEC 60118-4 standards and to ensure that the overspilling effect between adjacent rooms is as low as possible.

 

Wheelchair Bay Area for Audiences with Hearing Aids

 

Wheelchair Bay Area for Audiences with Hearing Aids

 

We focused on the wheelchair bay area, which has dedicated coverage for Wheelchair users who also happen to be wearing hearing aids. This ensures that comprehensive coverage is equal for standard seats and accessibility area seats.

 

 

Image from Shaw Theatres Balestier

 

Image from Shaw Theatres Balestier

 

Induction loops have significantly enhanced accessibility for individuals with hearing impairments, allowing them to enjoy public spaces, performances, and events with greater clarity and inclusivity. However, the overspilling effect on induction loops between adjacent rooms can challenge achieving optimal audio quality.

 

Conclusion

 

The overspilling effect in induction loop systems presents a significant challenge to achieving optimal audio quality and privacy in adjacent rooms or spaces. Factors such as proximity, loop design, and loop amplification influence the extent of the overspilling effect, requiring careful consideration during the installation and design phases.

 

However, strategic approaches and collaboration between professionals in the field can minimise the impact of overspilling and create inclusive environments for individuals with hearing impairments. Proper loop installation, design considerations, and fine-tuning loop amplification levels are crucial in reducing the overspilling effect and ensuring precise audio delivery to those relying on hearing aids or cochlear implants.

 

As technology advances, the accessibility landscape evolves, and solutions for overcoming the overspilling effect become more refined. Organisations like Listening Lab are at the forefront of providing hearing enhancement systems and services that fully empower individuals with hearing impairments to engage in various auditory experiences.

 

Contact Us

 

For personalised hearing enhancement solutions and to learn more about the latest advancements in auditory accessibility, enquire about Listening Lab today or call +65 6817 5100 to schedule a consultation and experience the transformative power of cutting-edge hearing technology. You can also ask for a quotation by providing us with the space requirements. Empower yourself or your loved ones with the gift of enhanced hearing and embrace a world of auditory possibilities.

 

AWWA School @ Bedok, Singapore

Featured Project

Hearing Loop Installation at AWWA School

AWWA School @ Bedok, Singapore

AWWA School is a specialized institution that educates children between the ages of 7 and 18 with multiple disabilities and autism. The school caters specialized education with multiple disabilities and autism to grow the potential for independence and improve the quality of life of students with special needs.

 

Located at 50 Bedok Reservoir Crescent, AWWA School at Bedok is a focal point serving children with autism. The school also delves into collaboration opportunities with their stakeholders to expose the students to the various platforms in the community, whereby they could develop, adapt and establish the skills they have acquired.

 

Flat Copper Tape to be implemented on top of Metal Flooring of AWWA School’s MPH
Flat Copper Tape to be implemented on top of Metal Flooring of AWWA School’s MPH

Multi-Purpose Hall

One of the key features of the school is its Multi-Purpose Hall (MPH), which is designed to accommodate different activities and events. However, implementing a hearing enhancement solution in the MPH proved challenging due to the high metal loss associated with the metal flooring.

Before installation, it is essential to understand the type of flooring used to help us develop a solution for the construction needs. The type of flooring used in AWWA School’s MPH is metal flooring.

 

Our biggest challenge was to overcome the high level of Metal Loss while implementing Flat Copper Tape to provide the electromagnetic field as part of the Hearing Enhancement Solution.

 

What is Metal Loss?

  • The presence of metals near a loop will result in the signals being “bounced” back, resulting in a cancellation of the loop signal to a certain degree, affecting the Hearing Aid user with the Telecoil function.
  • Common Metals found in installation sites would be:
    • Rebars or wire mesh in concrete floor/walls.
    • Metal reinforcement in walls or ceilings.
    • Overhead metal support structures.
  • Metal loss results in a loss of high frequencies which causes the sound quality to be muffled.

When metal objects are present near a loop, signals are bounced back, causing some cancellation of the loop signal. Rebars or wire mesh in concrete floors and walls, metal reinforcement in walls or ceilings, and overhead metal support structures are all common metals in installation sites. Metal loss causes a loss of high frequencies, resulting in muffled sound quality.

 

Metal Loss Test

Why is Metal Loss Test required before installation?

  • Crucial to carry out Metal Loss Test, especially when there is a significant metal content in the construction.
  • To ensure that customers do not have to over-invest in a costly loop driver when it is unnecessary.
  • To have a guaranteed preliminary result, the designed loop system with the necessary factors will perform within expectations. Flat Copper Tape will be implemented on top of the Metal Flooring of AWWA School’s MPH.

To ensure that the school will not over-invest in a costly loop driver, a Metal Loss Test is required before installation. This test is essential when the construction has significant metal content. The designed loop system with the essential factors can perform within expectations by conducting this test.

 

AWWA School's MPH Metal Loss Test
Metal Loss Test carried out at AWWA School’s MPH to analyze preliminary results before installation of Flat Copper Tape.

 

Type of Loop: Low Spill Multiloop

 

To contain the signal spill not far from the loop boundary. Usually used to prevent the magnetic field generated by the loop from causing interference with electrical equipment like electric guitars and dynamic microphones around the stage area.

 

Challenges faced: High Metal Loss

 

Metal flooring of the MPH will result in a muffled or dull audio quality for Hearing Aid users.

 

Solution

 

To overcome this, the installation team used two sets of C14-2Ns amplifiers, which is a higher capacity driver that allowed the driver to compensate for Metal Loss and achieve audio quality and clarity on par with or exceeding the IEC 60118-4 standards, also known as the International Performance standard for induction loop systems.

 

Fat Copper Tape

 

 

Finished Hearing Loop Installation at AWWA School
Finished Hearing Loop Installation at AWWA School

 

Contact Us

 

If you are looking to improve the accessibility of your projects for people with hearing disabilities, consider our state-of-the-art induction loop system. Our system is designed to provide high-quality, clear sound to hearing aid users by creating a magnetic field picked up by telecoil-enabled hearing aids.

 

Don't let metal loss or other acoustic challenges prevent you from delivering an exceptional client experience. Contact us today at +65 6817 5100 or email us at hes@listeninglab.sg to learn more about how our induction loop system can help you create inclusive and accessible spaces. You can also ask for a quotation by providing us with the space requirements.

 

NUS University Cultural Centre (UCC)

Featured Project

The Listening Lab’s Hearing Enhancement division very proud to be awarded the contract to build and implement a hearing enhancement system for the University Cultural Centre (UCC) of the National University of Singapore.

Located at 50 Kent Ridge Crescent, the UCC is a focal point for the University and its diverse cultural life and influences. The UCC has hosted Nobel laureates, foreign dignitaries as well as performances by Singaporean and international artistes. The UCC’s emphasis on building accessibility is what also makes the awarding of this tender to The Listening Lab very special to us.

The UCC renovation in 2018 provided a unique challenge to our team. It is a medium sized venue and has a hall for 1700 seats and a theatre for 455 seats and required hearing enhancement systems to be built in.

Hall:

New Flooring of UCC: Wood planks. Our approach was to implement Flat Copper Tape to provide the electromagnetic field as part of the Hearing Enhancement Solution.

Type of loop: Cancellation Perimeter Loop

The seating arrangement is not in a straight line. Moreover, the copper tape is embedded below the floor finishing, this could result in the chair installer bolting their seats onto the copper tape.

Challenges: The loop is very near to the stage, this could result in an “over spill” effect, which not only distorts signals but also could distort output from electrical musical instruments such as electric guitars or bass guitars.

Lots of coordination had to be done to make to ensure that during the chair installation, there is no damage to the copper tape that we installed.

Our solution involved installing a cancellation loop was installed before the perimeter loop, thereby reducing background noise was tremendously, avoiding the “overspill effect” mentioned above.

Theatre:

Type of flooring: Carpet – Flat Copper Tape

Type of Loop: Cancellation Perimeter Loop

Challenges: 

1. The cancellation perimeter loop is required to be installed onto retractable seating chairs. This can often result in damage to the loop when the chairs are retracted.

2. The installation of carpets might damage the copper tape as the carpet required to be cut after the installation process of the loop.

3. The installation of other fittings onto the retractable platform might also damage the copper tape as the copper tape was covered by the carpets, and therefore not visible to other contractors.

4. The copper tapes are installed on the different platforms therefore this could result in the field strength to be uneven.

Solution:

After an in-depth review, we provided this solution:

1. Holes to be drilled on the platform to connect all the copper tapes to the connecting cables below.

2. Detailed communication was conducted between us and the carpet supplier and warning tapes were placed on top of the copper tape before the carpet installation to ensure that the tape is not damaged.

3. Our team coordinated between the various vendors of UCC to ensure that anything mounted in the venue where our copper tapes were present, ensuring that other fittings did not damage our loop fittings.

4. Once the retractable chair drawing is received we had designed and repeated simulations for the cancellation loop to ensure that the field strength coverage is within the IEC 60118-4:2006. Our efforts were successful.

Our projects were successfully implemented and we're proud to have surpassed the IEC 60118-4: 2006 standards.

Madame Tussauds Singapore

Featured Project

Photo: theopentraveler

 

Madame Tussauds Singapore is a world famous Wax museum and tourist attraction at the Imbiah Lookout of Sentosa Island in Singapore. It officially opened on 25 October 2014 as the seventh Asian branch of the Madame Tussauds chain of wax attractions worldwide. Madame Tussauds Singapore is the only one in Asia that offers The Marvel 4D cinema experience.

 

 

The Listening Lab was awarded this project in Oct 2017 after its proposal to use a FM solution was accepted.  The project was commissioned in Jan 2018.

 

The FM transmitter was set up to interface with the Movie server where it produced a balanced signal in output. However as the FM transmitter requires an unbalanced input, an adapter was needed to convert the signal from balanced to unbalanced as shown in the photo below.

 

The hearing aid user will require to wear the FM receiver and neckloop around the neck. The neckloop will generate a magnetic field to communicate with the telecoil in the hearing aids, thereby allowing the user to hear directly from the audio source without surrounding interference

Madam Tussad diagram