So You Want A New Sound System?

In Uncategorized by tfwm

Most everyone in the congregation agrees a new sound system is needed. A variety of reasons are given by those polled. The clearest reasons are that the current system makes noises, is scratchy and disturbing, and service efforts by hired technicians don’t seem to solve these problems. Other than that, the system makes it just plain hard to hear what’s going on.

Start off the new sound system research process by identifying what the problems are with your current system. Technical issues are clear. If the system pops, clicks, buzzes or is otherwise intermittent or unreliable, these are obvious criteria for replacement.

If the complaint with the current system is that the spoken word is unclear, then opinions become very important. These opinions can manifest themselves in a range of responses. Some people think the current system is fine, some think it needs to be replaced, and some are ready to leave the church in search for a space where the service can be heard and understood.

Many times, the design consultant or contractor will find themselves in the middle of these differences of opinion, and unless people skills are employed, no answer will be acceptable to the church representatives. Unless this outside designer separates these issues, no amount of calculation will provide an acceptable solution.

The current system should be reviewed in light of established technical criteria. The more the outside designer can separate engineering issues from emotional issues, the more of a success the installation will be. The worship group’s purpose in gathering is not technical, but spiritual. To address this detail, most worship groups will appoint a committee to represent the church and meet the prospective designer and review the proposed solutions. Here are the elements for technical evaluation which can be used with this committee to isolate documentable problems and find identifiable results:

Level
The sole purpose of a sound system is to provide an adequate listening level at each listener’s ear. This statement is immediately open to challenge because the sound system also reproduces sounds which otherwise would not be reproduced into the space (output from a keyboard for example). But, in terms of basics, the spoken word is generally the most important content delivered by the sound system. The leader’s 65 dB SPL (loudness) cannot carry from the front of the space to the back with enough level to supply signal for all the bodily absorption provided by the congregation.

Coverage
Can every member hear in every seat in the sanctuary? This hearing mandate extends from the front row to the back row and from side to side. This hearing mandate includes not only the congregation, but also separate purpose groups such as the choir. The choir not only needs to hear, but may want to hear some additional material. Coverage may need zones in the case of the choir.

Uniformity
The level might be fine, but is uneven- allowing some congregation members to hear, while others do not. The uniformity of the current sound system must be understood in order for complaints to be addressed. Acoustical comb filtering can easily provide clear audible sound next to a seat with inaudible listening. Whether studied with meters and reproduced pink noise or by listening to known (or unknown) content delivered by a reader or from a recording, the uniformity should be technically examined.

It is also of primary importance to study uniformity from the human side. Many people sit in the same seat all the time during worship – even if the seat provides poor listening. If there is a vocal complaint, find out where that listener tends to sit and listen at that seat and listen to that person. It is not only important to technically verify the acoustical shortfall, but also vitally important to listen to the person who is complaining. Besides technical uniformity, all persons who are part of the purchase must feel as though their reasons for seeking a new system are listened to and addressed.

Reverberation
This criteria might be called clarity. Speech intelligibility is diminished by reverberation. Musical richness is enhanced by reverberation. Reverberation is multi-path sound arriving at any listeners ear with multiple arrival times. This provides the sense of “room”. While the “roominess” makes a Bach fugue choral performance rich, the multiple ear arrivals will slur speech and make it hard to decipher. There are many solutions for these basic differences in listening speech versus music criteria. But, the most important basis for design is to understand what is most important to the worship group. This is sometimes denominational where one worship group relies heavily on music while another will have only incidental music as interludes to the spoken word. The system designer must understand what is important to the worship group in order to work with the appropriate criteria in mind. These same criteria form the basis of judgment of the final installed system.

The above criteria are the most important for the listener. There are other technical criteria, but the listed criteria are an appropriate start. But what are the user issues?

A mid twentieth century church might have a four channel mixer-amplifier, a couple of microphone receptacles and a loudspeaker behind a grill cloth in the front of the room. Power on and power off were the controls. There is a certain simplicity in that one-button control which is honest and unencumbered. Less is more. All people concentrate on the purpose for being together.

This simple system approach can be the appropriate system for any number of worship groups. This simple concept can, of course, be updated to wireless microphones, may have better loudspeakers, may indeed have better electronics, but the simplicity of the project is intact. Simple system, simple problems.

This simple system, of course, may well represent significant engineering including acoustical prediction and treatments, analog or digital electronics and may even include sophisticated loudspeakers placed carefully. But, the user truth is simplicity and uncomplicated operation: On and Off switch and maybe a volume control. The system without the volume control will, of course, operate more reliably and may well teach the system users how to use a microphone.

Large worship spaces with active music programs and architecturally complex spaces will need the deft control of an operator. If the sanctuary, the congregation or the music ministry is large, or if the room is used by other large groups, a simple system may not work. Many musicians will require many microphones. Musicians will have keyboards, guitars and other non-microphone signals to amplify and reproduce. There are other microphones for liturgical ministers.

When multiple microphones are in one room, and if the loudspeakers are in the same room, gain before feedback immediately becomes an issue. The number of open microphones is limited by system gain and room acoustics, as well as the sensitivity of the loudspeakers and the microphones themselves. A console mixer is needed with an operator who understands the gain achievable in the room and knows the number of microphones that can be ON at any given time. That person looks for who will be speaking or singing and anticipates the needs of the presentation. That person directs focus in the room. If that operator misses a cue and someone sings or speaks into a dead microphone, they “take stage” and call attention to the system and to the shortcomings of the event. That person must be trained and sensitive to the production values of the staging. The success of the live mix and the sound system depends on this person’s skill.

The sound committee looking to revitalize, upgrade, redirect or otherwise change an existing sound system must make a critical choice as to the use of the new system. The speech reinforcement use is fundamental. The playback use is fundamental. The control is a critical decision. Hands off or hands on.

Although many churches now feel they must have a sound mixing desk in the middle of the room, this is not necessarily the case. It can be distracting to the congregation and very embarrassing to the technician when they miss a cue. If the worship events can manage without a hands-on mixer operator, suggest it. There are many churches who installed a mix position in a new facility and found very quickly that they didn’t have an operator much less a qualified operator.

Similarly, patch panels have been installed in many worship spaces to provide flexibility. Because patch panels can, over time, generate noise, and if they are never used, they may not be a wise use of the system dollars.

Recommendation: Begin the process by identifying how much speech and how much music is typical to the sound system’s use. Start the system design small. Add to the system as you can justify each addition to the basic system. This advice works for large systems as well. Differentiate between toys and tools. Anything added to the sound system should be a tool to accomplish a stated purpose. Shopping for features can encumber the system with toys that get in the way of good audio. Leave all controls out of the system that aren’t needed. A console mixer is a great place to lose signal in a rush or in a complex working environment. And most importantly, make sure everyone agrees with the system approach. Does the new system meet all the stated goals and does it meet those goals in an order that puts most of the fiscal effort where it counts the most?