Public Address in a House of Worship

The public address or sound reinforcement system fitted in a House of Worship is the single most important support system to deliver the Message.

Internationally IEC and NFPA standards have been defined since 1991 to specify the minimum requirements for intelligible speech. These standards have not been implemented in South Africa and little local expertise exists to identify and address this issue.

The sound system and acoustic demands for a House of Worship is more complex than any other institution of it's size as the following functions must be fulfilled during a Worship service:

  • Convey the spoken word without causing fatigue or stress by trying to hear rather than understanding what was said
  • Acoustically enhance congregational singing
  • Accurately convey choral singing
  • Cater for special music and lecture events
  • Each of the above functions require very specific acoustical and sound reproduction capabilities which is the equivalent of having a room capable being a cathedral, lecture hall, symphony hall and a recording studio all at the same time.

Acoustic Analysis

Acoustic analysis quantify the performance of the sound system and the room response based on predefined acoustical criteria determined by the specific usage of the room/venue. Precisely calibrated measurement equipment capable of the highest noise immunity available on the market is used to simulate the operational environment while analysing the following parameters:

Room Acoustics
  • Noise Control Level (background noise), echo’s and late reflections
  • Room Reverberation Time (rate of decay of sound) using advanced Time Delay Spectrometry (TDS) analysis methods
  • Speech Articulation and Intelligibility in accordance to the Speech Transmission Index (STI) as defined by ISO and ANSI Standards
Sound System Performance
  • Sound distribution, level, phase alignment, headroom, quality and added reverberation
  • Sound system articulation, realism, intelligibility, amplification, alignment and hearing enhancement capabilities

The findings of the analysis are summarised in a concise report which will clearly identify any issues and discuss how improvements could be made based on various costing options contained within defined budgetary limits.

Acoustic Correction

Acoustic treatment is required when the room/venue acoustics are not suitable for amplified sound and the acoustic incompatibility is beyond the ability of the signal processing equipment to produce intelligible sound.

Most Places of Worship are designed with little or no consideration of the sound reinforcement requirements as most older churches and cathedrals were designed for the natural spoken word and the pipe organ performance, whereas modern designs make use of highly reflective surfaces such as glass, steel, granite and marble which causes additional unwanted reflections.

In most cases the room is too reflective/reverberant for amplified sound and the walls and/or ceiling require treatment in order to absorb certain sound frequencies to create a uniform and intelligible sound field. more

This is achieved by the installation of specialised perforated plasterboards or slotted wooden strips backed by various sound absorbing material designed to reduce specific problematic frequencies.

The selection of the most suitable type, position and size of the acoustic treatment is identified and optimised through the use of an acoustic computer simulation system in conjunction with actual on-site acoustical measurements taken to ensure the maximum speech intelligibility for the investment made.rly identify any issues and discuss how improvements could be made based on various costing options contained within defined budgetary limits.

Natural vs. Amplified Sound

The fundamental principal of amplified sound stands in stark contrast to the natural sound model.

Natural sound/acoustics originate as  a single source and propagates in an omni-directional manner through the room. The room is used for sound transmission enhancement through reflection/reverberation of the sound source  to create a uniform sound field in the room.

Amplified sound originate from multiple sound sources which propagates in directional sound fields focused on specific areas/partitions within the room, uniformity is reached through acoustically matching of the various partitions.

Natural sound requires a reflective environment and amplified sound an absorbent environment

As natural sound alone cannot meet the demands of the modern places of Worship, the goal is to seek a uniformity for the natural and amplified sound models which is often diametrically opposed.

Through optimal sound system design it is possible to reach a common ground

Design, Installation and Maintenance

The implementation of a sound reinforcement system is completed through the following phases:

Preliminary Design

The initial design is completed based on data acquired during the site survey or acoustic analysis conducted to propose solutions relating to various costing options. Equipment selection is done based purely on the available budget and sound reproduction requirements and is not specific to any brand, drawing from a vast supplier base and a multitude of installations where equipment from entry-level to high-end brands have been successfully implemented.

If budgetary constraints does not permit full implementation of the required functionality, a phased approach will be proposed without compromising overall system quality (by limiting functionality and not quality).

Final Design

Once a solution has been agreed upon, a comprehensive design is conducted using 3D acoustic modelling and simulation methods to predict and optimise the system’s performance and venue’s acoustic response.

Installation and Commissioning

Installation is completed using an in-house team of technicians and graduated engineers, according to tried and tested methods refined over 2 decades. Mandatory training is included during the handover as it is imperative that operators are adequately trained.

Support and Maintenance

To ensure a long service life of the system and correct operation, it is imperative that operators are adequately trained and the system maintained to remain at optimal operating levels.

We offer the following services as part of the installation and ongoing system maintenance:

Post-implementation system training covering the following:
  • Stage layout and with regard to choir/vocalist, hook-up of instruments and microphones positioning
  • Operator training in mixers, crossovers and microphones to maximise intelligibility
  • General ongoing operator maintenance tasks
Annual system maintenance consisting of the following:
  • Checking of all sound system equipment including rigging and wiring
  • System tuning and recalibration
  • Follow-up operator training