PAVA System | What it is and How to Design One
How to use this document for designing PAVA Systems
Below are some effective strategies and techniques that serve as a guiding framework for PAVA systems. These approaches are beneficial for a wide range of environments, including public spaces, commercial establishments, Staida, and power stations…
This comprehensive PAVA checklist encompasses various crucial aspects such as: system design, intelligibility and common budgeting errors.
If you aim to improve your PAVA system design performance in 2024, you will find immense value in today’s checklist.
Let’s delve into the details…
PAVA System Research Checklist
Before embarking on a PAVA system project, thorough research is crucial to understand the specific requirements and constraints of the installation environment.
1. Assess the Venue
It is essential to start your design by measuring the dimensions of the venue and evaluating its layout to identify optimal locations for loudspeakers and microphones. This will help in determining how sound will propagate and be perceived in different areas of the venue.
By assessing factors such as reverberation, ambient noise levels, and potential sound obstructions, you can strategically plan the placement of audio equipment for maximum effectiveness.
Additionally, consider the specific requirements of the venue, such as seating arrangements, audience flow, and critical areas that need audio coverage.
It is important to analyse the venue comprehensively to ensure that the placement of loudspeakers and microphones caters to the audience’s needs and provides clear and consistent sound reinforcement throughout the space.
2. Identify Your Audience
Identify the demographic profile of the audience, including potential hearing impairments or age-related hearing loss. Make sure to refer to accessibility guidelines to ensure that the PAVA system accommodates individuals with hearing impairments or other special requirements.
Engaging with attendees through surveys or interviews is a good way to understand their audio needs and preferences, especially regarding clarity and volume.
3. Research Your Industry Specific Guidelines
To ensure regulatory compliance in a PAVA system project, familiarise yourself with the relevant standards and regulations governing PAVA system design and installation. This involves researching industry-specific guidelines, local building codes, and safety regulations to ensure that the system meets all necessary requirements.
By understanding and adhering to these regulations, you can guarantee the safety, quality, and legal compliance of the PAVA system installation.
4. Don’t Ignore The Smaller Costs in Your Budget
Start by researching and compiling a list of required audio equipment, such as loudspeakers, microphones, amplifiers, mixers, and cables. Obtain price quotes from reputable suppliers or manufacturers to estimate the equipment costs accurately.
Consider any necessary accessories like mounting brackets, connectors, and power sources that may add to the overall expenses.
Next, factor in the costs of professional installation services. Contact certified audio technicians or installation companies to provide quotes for the installation process, including labour charges, cabling requirements, and any specialised tools or equipment needed for the installation.
Furthermore, account for ongoing maintenance expenses to keep the PAVA system in optimal condition. Research service contracts offered by audio equipment providers or maintenance companies to estimate the costs of routine servicing, repairs, and software updates.
Including these maintenance expenses in your budget will help you plan for the long-term sustainability of the PAVA system and ensure its continued functionality and performance. By meticulously detailing the equipment, installation, and maintenance costs, you can create a comprehensive budget plan that covers all aspects of the PAVA system project from start to finish.
Criteria Checklist
Now it’s time to find a reference point for evaluating the effectiveness and efficiency of a PAVA systems design.
1. Consider The Sound Volume
Ensure that the system can produce adequate volume levels to reach all corners of the venue without distortion.
The sound produced must reach a high volume level to ensure it is comfortably heard by all individuals within the hall with reasonable hearing abilities. It is crucial to cater to the needs of the audience, including those who may be hearing impaired through the provision of an induction loop system
2. Check Intelligibility
While achieving adequate volume is essential, it is not the sole focus. Equally important is the aspect of intelligibility.
A successful public address system should not only amplify sound but also ensure that the speech is clear and easily understood by the listeners. Unfortunately, many systems fail to deliver on this crucial requirement.
Verify that speech reproduction is clear and easily understandable by all listeners, regardless of their position in the venue.
3. Understand Natural Sound Reproduction
Though less critical, it is highly desirable for the system to produce sound that appears natural to the audience.
The ultimate goal is for individuals to be unaware of the system’s presence and feel as though they are listening to the speaker’s voice directly – at a comfortable volume level.
Many systems unfortunately fail in this regard. Success however can be achieved if organisers can create an environment where effective communication between speakers and audiences can thrive.
Strive for a natural sound quality that mimics direct human speech. We’re not after a speaker system that screams, “I’m compensating for something” in a teenager’s first car; we’re aiming for something more subtle and less “mid-life crisis” inducing.
Buying Checklist
When procuring equipment for a PAVA system, consider the following factors:
1. Microphone Directivity
Microphones used in public address systems come in different directivity patterns, each serving a specific purpose:
Omni-directional – picks up sound from all directions.
Cardioid – having a heart-shaped polar response, with a high rejection of sounds from the rear, but reduces sounds from the side by only a half [-6 dB]
Supercardioid – has a greater side rejection than cardioid.
Hypercardioid – Maximum side rejection, though potentially less rear rejection than cardioid, offering the greatest total off-axis rejection.
While cardioid microphones are suitable for mounting on stands with the rear facing the audience, they are not ideal for handheld use where the side faces the audience. In such cases, supercardioid or hypercardioid microphones are preferred due to their superior rejection of unwanted sounds.
Select microphones with appropriate directivity patterns (e.g., cardioid, supercardioid) based on their intended use.
2. Don’t Neglect Frequency Response
Another crucial aspect of microphones often overlooked is their frequency response. Microphones should ideally have a flat frequency response without peaks to prevent oscillation.
Oscillation can occur if a response peak surpasses the feedback point, even if the overall sound level is below it. Microphones with flat responses allow for higher sustained sound levels and are easier to control compared to those with peaks.
Unfortunately, microphones combining super cardioid or hypercardioid characteristics with a flat frequency response are rare. Moving-coil microphones typically exhibit response peaks due to mechanical resonance, although higher-quality ones are dampened to some extent.
Some electret microphones provide good directivity and a smooth response, but many are limited to cardioid patterns with peaks in their treble response. By understanding these microphone attributes, public address systems can be optimised for clearer and more controlled sound reproduction.
Choose microphones with flat frequency responses to prevent oscillation and ensure controlled sound reproduction.
3. Loudspeaker Placement
Position loudspeakers strategically to achieve optimal coverage and minimise feedback issues (More of this below don’t worry).
4. Use a Quality Amplifier
Amplifiers are essential components responsible for increasing the strength of audio signals to drive the speakers. They help ensure that the announcements or emergency messages broadcasted through the system are clear and audible across the designated areas.
These amplifiers are typically connected to the control panel and speakers via cables to transmit and amplify the audio signals effectively. The power output of the amplifiers is selected based on the size of the area to be covered and the required sound levels.
Amplifiers in a PAVA system need to be reliable and capable of delivering consistent performance, especially during emergency situations where clear communication is critical. Regular maintenance and testing of the amplifiers are necessary to ensure their proper functioning and readiness for any potential emergencies.
5. Don’t Forget Your Reliable Cable
Don’t ignore the price of small things such as cable. Cables are responsible for transmitting audio signals from the control panel to the amplifiers and speakers throughout the designated areas.
The quality of the cables used is essential to maintain the integrity of the audio signals and prevent any interference or signal loss. Proper installation and routing of the cables are also important to ensure efficient communication between the components of the system.
6. Focus on Backup Power Supplies that are Tried and Tested
The backup power supply in a public address and voice alarm system is a critical component that ensures the system remains operational during power outages or emergencies. It provides a secondary source of power to keep the system running when the primary power source fails.
Having a backup power supply is essential for maintaining communication and broadcasting emergency messages in situations where mains power is unavailable. This helps to ensure that the public address and voice alarm system can continue to function effectively during critical times when reliable communication is paramount.
Regular testing and maintenance of the backup power supply are necessary to guarantee its readiness and reliability when needed. It is important to have a backup power supply that can sustain the system for an extended period to support continuous operation until power is restored.
Intelligibility Checklist
The second requirement for effective communication. Intelligible speech, even when presented at moderate or low volumes, holds more value than incomprehensible speech at high volumes. Understanding the factors contributing to speech intelligibility is crucial in maintaining it during reproduction.
1. Use Monosyllabic Nonsense Words
In standard intelligibility tests, volunteers are scattered throughout an auditorium noting down what they perceive the speaker reads out. The accuracy of these responses provides the Percentage Articulation Index (PSA) of the system. Monosyllabic nonsense words such as baboon or hippopotamus will be spoken and recorded by these volunteers to assess the intelligibility of the system.
Achieving a 100% articulation index is practically unattainable
95% is considered exceptional but rarely reached
Around 80% articulation can lead to reasonably good audience comprehension
At 75% increased concentration becomes necessary
Below 65% indicates poor intelligibility.
A realistic goal is to target a PSA between 80% and 95%, aiming for over 90% if feasible.
2. Consider Age-related Hearing Loss
As we all are becoming aware, hearing deteriorates. Hearing impairment due to age-related hearing loss, known as presbycusis, will seriously affect audibility at higher frequencies. The auditory response of a 50-year-old to 4 kHz frequencies is typically 10 dB lower than that of a 20-year-old.
By age 60, this decline worsens to around -24 dB at 4 kHz and extends to lower frequencies.
Prolonged exposure to excessive noise can also lead to hearing damage, primarily affecting higher frequencies crucial for consonant reproduction and speech comprehension.
Public address systems distorting high-frequency bands or favouring low frequencies often result in poor intelligibility, with older individuals experiencing more significant challenges due to age-related hearing loss.
Assessing system performance solely through brief listening tests may not provide a comprehensive evaluation, as perceptions can vary based on listener age and speaker quality. Conducting PSAs with individuals of different ages can offer insights, although this approach may not always be practical.
The most effective strategy is designing the loudspeaker system based on sound acoustic principles from the outset to optimise speech intelligibility across diverse audience demographics and environmental conditions.
3. Don’t Distort Speech
Feedback, even at lower levels, can distort speech with reverberation, ultimately compromising intelligibility. To counteract feedback, it is essential to maintain the operating level well below the oscillation threshold.
This precaution can result in inadequate volume, particularly with softly spoken speakers or those who neglect microphone usage.
One solution is to design the system in a way that raises the feedback point, thereby delaying feedback oscillation until a higher volume level is reached.
Feedback typically reaches the microphone through two avenues:
- Direct sound from the loudspeakers;
- Indirect sound reflected from the auditorium walls.
Direct sound feedback can be mitigated by employing directional loudspeakers that direct output towards the audience and away from the microphone.
Indirect sound feedback, reflecting off walls and ceilings, is challenging to eliminate completely but can be minimised by positioning loudspeakers to avoid direct sound towards reflective surfaces. Utilising super-cardioid or hyper-cardioid microphones can also aid in reducing the pickup of indirect sound. Given that indirect sound reaches the microphone from various angles, rejecting sound from sources other than the intended source helps reduce feedback.
Bonus #1: Achieve Natural Sound in PAVA Systems
Striving for a natural-sounding public address system is a key objective, regardless of installation size. While larger setups present challenges, both small and large venues can incorporate techniques to enhance natural sound reproduction.
The ultimate goal is for the sound to appear as if it solely emanates from the speaker, albeit with sufficient volume to fill the entire space.
1. Maintain Unity in Small to Medium Sized Areas
In small to medium-sized halls, where the speaker is in close proximity to the front rows, moderate sound reinforcement suffices as the natural voice can be heard directly. The reinforcement should seamlessly blend with the speaker’s voice to maintain a sense of unity.
As the distance from the speaker increases towards the rear of the hall, where sound primarily originates from loudspeakers, efforts should be made to ensure that the sound still appears to originate from the platform. A frontal source location, ideally centralised in the same plane, contributes to achieving this effect.
2. Address Challenges with Traditional Systems Early
Traditional systems often struggle to achieve this natural sound source location. Column speakers provide a frontal source location, but for most of the audience, the source is perceived from the side where the columns are typically placed.
Ceiling matrix systems pose even greater challenges as sound comes from overhead or behind the audience in many positions.
3. Don’t Distract the Listener
In addition to natural source location, the sound quality should exhibit a natural tone devoid of “boominess”, harshness, or tonal defects. Such imperfections not only impact intelligibility but also draw attention to the sound system rather than the speaker, potentially causing listener distraction.
4. Optimise Location Over Audibility
While some may prioritise sound audibility and comprehension above all else, disregarding source location and tone, these elements play a significant role in audience engagement and comfort. Deviations from natural sound can lead to subconscious mental fatigue and reduce audience attention span, underscoring the importance of naturalness in sound quality.
By addressing these fundamental requirements of naturalness in public address systems, the design and implementation of loudspeaker systems can be optimised to create an immersive and engaging auditory experience for diverse audiences.
Bonus #2: Planning Reliability
Picture this, your stadium is hosting a local event with speech and music blaring out the speakers. After the wine and cheese has been brought out, the public address system goes dead. Frantic efforts to restore the sound fail. The lesson? Build Reliability into the system.
1. Standby Equipment
Power amplifiers are the most vulnerable part of a system being at the mercy of any fault on the loudspeaker feeders. They often become hot and as we are all aware heat equals red flags in this industry!
Amplifier capacity should always be greater than required.
To achieve this use a standby amplifier that isn’t normally in use or under-load the amplifiers that are being used to allow for some wiggle room.
2. Microphones
Without telling you to suck eggs, always check batteries for wireless microphones before events. A second microphone already connected is a great solution when in fast pace fixing scenarios. Adding one to a spare channel on the mixer will mean no scrambling to disconnect and reconnect a new one.
3. Loudspeakers
Luckily most loudspeaker faults won’t result in a full system failure with the exception of the rare loose cable causing the circuit to short. A loudspeaker that is used often will vibrate as reverberation occurs. Voice alarm systems must be fire resistant so cables are fitted into ceramic screw terminals that often need to be tightened down. As the unit vibrates these screws can become loose with the wire falling out as a result. If these two wires merge a short circuit can power down the whole system. This again is very rare.
4. Cables and Feeders
The most common used to be stadium microphones that were moved from desk to desk causing the cables to flex and bend however due to upgrades in fixed positions we don’t often see this anymore.
Now the most common issue is in high rise office buildings where a fit out companies come in to renovate a floor to shell, often cutting cables and ignoring them in the process. This unfortunate issue can’t be fixed on the fly and will require a team to re-cable the system.
5. Power Supplies
This one is unlikely to happen during an event however it has been known to happen. A battery/ mains amplifier available as a backup is a good idea
Your Free PAVA System Standards Checklist
Okay I know you want to crack on now. But before you do, remember to list the standards the site now complies with (it’s nice to show off after a job well done!). View our free checklist here.
To Conclude
I hope this article helps you in your PAVA System design.
But before you get started on the checklist, I’d like to hear from you.
What did you think of this post?
Or maybe you disagree with something you read.
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