In a day of mail order mania and cost consciousness, remind your church sound customers of some basic truths
by Pat Brown
A letter to a church sound committee might read:Thank you again for the opportunity to provide you with a proposal for the sound system for your house of worship. While we appreciate your interest in “good stewardship” in the funding of this project, and understand your request for “church pricing” for the work, the following points should be kept in mind when determining the best value for the dollars spent.
#1 – Dynamic Range
Church sanctuaries are usually quieter than other “places of gathering,” and as such the sound system must be quieter than usual to prevent audible noise in the audience area. Our proposal provides for 96 dB of dynamic range in the system electronics – a figure typical for recording studios and other critical listening environments. This extended dynamic range assures that the signal chain will not be the “weakest link” when it comes to overall system performance.
Audio equipment is not “plug and play.” There are no strict standards that all manufacturers follow when establishing the operating parameters of their equipment. All electrical devices produce noise – that annoying “hiss” that can be heard in the background on some systems during quiet portions of the service. Audible hiss can be eliminated from a sound system if its gain structure is adjusted properly. This process is carried out after the system in installed, and when done properly, will result in the best possible signal-to-noise ratio for the system. Our proposal includes an accurate and meticulous optimization of the gain structure of the sound system.
#2 – Energy Ratios
Many listening environments have a “sweet spot” for which the sound system performance is optimized. In a house of worship, every seat must be optimized for adequate signal-to-noise ratio and suitable early-to-late energy ratios. Our proposal provides a minimum of 25 dB signal-to-noise ratio (soft music) and a positive early-to-late energy ratio for your type of worship – for every seat in the audience area.
#3 – Uniform Coverage
Many auditoriums are plagued with “hot” and “cold” spots in the sound coverage. This can usually be attributed to interaction between multiple loudspeakers, and is unavoidable when more than one loudspeaker is required to provide sound coverage for the audience. A good design assures that there is even coverage in the audience area, and that no seats are rendered unusable by loudspeaker interaction. Our design addresses this critical issue, assuring you that there will be excellent sound quality at every listener seat.
#4 – Versatility
While it is possible to design sound systems that are optimized for speech OR music, your system must perform well for speech AND music. Since the attributes of these two types of systems are often at odds, this is a very difficult design task. The proposed system has the accuracy and clarity required for speech reproduction, while maintaining the extended frequency response, imaging, and power handling required for music.
#5 – Hum and Buzz
Audible hum is a major detriment to a church sound system. It usually results from improper grounding practices, either in the installation of the wiring or the actual equipment. Off-the-shelf equipment often requires special grounding practices to work without hum. The proposed system shall be grounded properly, and all system wiring shall be routed and shielded properly. The proposed equipment will be tested for proper grounding, and and suitable modifications made when necessary, ensuring “hum-free” operation.
#6 – Gain-Before-Feedback
Whenever a microphone is placed in the same room as a loudspeaker, the potential for feedback exists. Things that aggravate this further are multiple microphones and long miking distances – necessities for most churches. Two things are required for a system to work properly.
1. The sound system must be extremely stable, meaning that loudspeaker array design and mic placement are critical to the end result.
2. Your sound personnel must understand the limitations of the sound system and be trained to manage the open microphones and working distances for people using the system.
Our proposal addresses these issues, providing a stable system along with operator training to assure that feedback does not hinder the performance of the system.
#7 – Wireless Microphones and RFI
Sound systems can be adversely affected by frequencies above the audible band. They must be properly shielded against such, and appropriate filtering devices must be installed when required.
Wireless microphones provide some excellent benefits for houses of worship. These are actually small radio stations that broadcast on a specific frequency. Each wireless device needs its own frequency, which means that an RF survey must be performed to produce a documented frequency allocation table. The selection of frequency is critical to the mic’s proper operation, as well as to avoid interference with other wireless products used in the venue. In addition, the operating frequencies for your wireless products must be carefully selected to work properly in the presence of other RF broadcasts in your area, including digital television.
#8 – “Clean” Installation Practices
An important yet often overlooked aspect of a sound system design is the installation of the system. It is imperative that proper interconnect practices are carried out, and that all applicable electrical codes are observed. A “clean” installation means that wiring has been concealed as much as possible, and that the finished system blends well with the decor of the building. Wall plates and connectors must be wired properly for the system to work correctly. Our proposal includes a meticulous check of all cables for proper termination and identification. A system wiring diagram will be presented to you upon the completion of the system so that future modifications to the system can be made efficiently and at the lowest possible cost.
#9 – Professional Equipment
There are many brands of equipment available in the audio marketplace. Fortunately, there are many reputable professional audio companies that make equipment suited for your needs. There are also low cost “knock offs” that appear to be equivalents to pro gear. Our proposal only includes equipment from reputable companies. Our years of experience in the audio field have enabled us to eliminate marginal equipment from our inventories. We deal only with companies that provide reliable, repairable products. All proposed loudspeakers have been “stress tested” for rigging safety, and can be suspended above a congregation with confidence. In addition, all equipment meets applicable codes for fire safety and radio frequency emissions.
#10 – Calibration, Training and Documentation
A properly calibrated sound system will be much easier for your personnel to operate. A significant amount of expertise is required to make a system “user friendly.” The proposed system must be calibrated (or “tuned”) using advanced audio and acoustic instrumentation. Upon completion of this process, all controls that do not require user adjustment must be rendered inaccessible.
After calibration, your personnel will be trained to operate the system, and a user’s manual shall be compiled which will include equipment manuals, system wiring diagrams, and operating instructions.
In conclusion, your sanctuary is a critical listening environment for speech and music. As such the sound system must provide adequate acoustic gain, intelligible speech, even coverage, and extended bandwidth to all listener seats. The best value in a sound system is one that meets all of these criteria. Such a system will provide years of trouble-free service and serve to complement your worship services.
There is much more to a sound system than acquiring some equipment. An audio professional can work with you from the planning stages and save you considerable time and money on your system. Most importantly, you will have a system that has been tailored to your specific performance needs and aesthetic requirements, and money spent in the future can be used to compliment the existing system rather than replace it. pb
The average house of worship purchases four sound systems before they get one that meets their needs…
*This article first appeared in Practical Audio – A Technology Blog by Pat Brown