New Construction — Room Acoustics, Part 2

In the first part of this two-part series, published in September, a wide variety of acoustical solutions and issues specifically focused on dealing with a space that already exists were discussed. Although the basic concepts and applications outlined in that article apply regardless, the issues and problems of a new building are in many ways very different and if properly planned for and managed can lead to a dramatically better acoustical environment for your worship service.

But the opposite is equally true. Without substantial advanced planning, evaluation of options, discussion of possible paths, you can end up with a nightmare.

Which of these outcomes you achieve is entirely driven by what you do before you start construction.

Congratulations!

Your congregation has finally achieved its goal of raising what you hope is enough money to build a new permanent home for your worship service. It may have taken years to get here, but whatever the time and effort expended to this point, the key to final success on any worship space project is discussion!

The most critical step you can and should take at the outset is to have a series of open meetings or discussion groups with everyone who has any stake in the project.

In far too many instances, a small group or committee is formed to handle this initial stage of the building’s developmental process. In our many years of experience, it has proven to be a fact that a lot of the problems that arise with a project come from the nature and constitution of this group. If all potential or actual “users” are not represented and heard, then they and their actual or perceived needs and wants will become a problem at some point later — often too late.

Establishing a complete very high resolution picture of not only the worship aspects of the building’s use, but also the various other likely uses that will happen (despite the “that will never take place” statements made initially), is essential to defining what kind of building you need and how it should be designed and constructed. (Never is a very dangerous assumption to make for any building in which the surrounding community is involved.)

It’s not just the physical plan and layout that matters, it’s the people based functionality of these aspects (see architects below) that matters equally if not more to the success of any space.

Well before you get to the worship aspects of the new building start making lists of what else will be going on, who will be using the space(s), for what, when and what their needs are above and beyond those that are part of the primary design for worship. Plan for the “never” ideas, the five years out concepts and the hopeful vision of congregational growth as well when making your lists. If you don’t make that part of the discussion now it will come back around to be an issue at some point — guaranteed!

The Critical Non-Worship Acoustic Issues

This is especially important when it comes to acoustical considerations. Although all worship space acoustics should be sharply focused on the principal goal of helping people to hear what they expect and need to hear (the service and the word/sermon specifically in most cases), there are a large number of other considerations that if not recognized, planned for and accommodated, will lead to avoidable and expensive retrofit solutions. For example, if your new HOW is going to offer a day-care or after school space or a privacy room for new mothers and infants, consider the needed noise isolation between those spaces (from each other) and from the main worship auditorium/sanctuary space.

Another classic example from one recent project we completed was the control of noise from the attached school gymnasium, which had been added to the original building plan when additional funds were donated. Think about the amount of noise several hundred parents and families can make at a sixth-grade basketball game on a Friday evening while there is a senior’s service going on in the auditorium.

If proper noise isolation and control had not been built into the construction plan, the facility would have had timing buzzers and referee whistles as a background soundtrack to the worship service. Certainly a less than ideal situation, but one that can be and was controlled by proper advanced planning and design.

Making a List — In Fact, Making a Whole Lot of Lists

Depending on the type of building envisioned and its role within both its particular faith community and the community at large (see the examples above), you will have a lot of things to consider and evaluate with the architects, general contractors and others involved in the project.

Collecting and weighing the various needs and their impact on the building itself and its acoustical design are going to be an eye-opening experience. You will be surprised at how many things can contribute to various issues and what their impact is or might be.

So this first list is going to be a long one. Without judging or valuing any of the items simply create a list of what everybody wants. Each individual may represent a different aspect of what needs to be considered when planning the overall sound and relevant acoustical requirements.

We are not looking for, nor should we expect, acoustical expertise here — what you should be looking for are perceptual desires. By asking for this input, you get to the truth of all users’ needs, requests and frustrations. When this list is complete, only then can you intelligently sit down and really start to build, plan and design. You will know what people think, they will know they have been asked and heard, and the whole process has structure and logic.

The Architect, the General Contractor and the Vision

Every new house of worship comes with a vision from its congregation. That vision, the totality of the goal of the project is most often not adequately defined or presented in a form understandable by architects, general contractors and the many other professionals and trades who will be a part of the project.

The biggest problem with most building committees or councils is too many chiefs, each with his own agenda and goal. The point of the list development exercise outlined above is to reduce that fragmented set of outcomes to a singular focus on a specific set of results.

The other major point of contention is between the “vision” presented by the architect/design team and the goals of the HOW itself for its new building. It is crucial that the people who will be managing the building’s construction internally instill in the architect a clear and precise definition of what they expect. This will normally require more than one version of the initial plan and drawings until the concepts desired by the people paying for and who will use the HOW and the development of those concepts into a viable building plan meet up and agree.

The same issues must be handled with the chosen general and sub-contractors to ensure that they fully understand and can execute the architect’s plans and the HOW’s vision to produce a final result that meets the targeted goals.

While many will feel that they should fully trust in the expertise of their construction and design partners, it is incumbent upon the “owners” to communicate effectively and repeatedly every specific point generated by the lists you created. DO NOT assume the architect, contractors or anyone else except you fully understand these critical requirements until they have shown by their execution on the project that they do.

The Sound of Your New Space

Now it time to get down to the details and deal with the acoustics. Again, do not assume expertise in this area by anyone except a specialized acoustical consultant (which I strongly recommended you consider using). The general practices within the architectural and construction professions do not generally effectively handle the specialized acoustical issues unless they are pointed out again and again and again. It only takes one sloppy drywall install or poor isolation of an HVAC duct system to completely ruin the desired acoustics of the sanctuary and other worship spaces.

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When you are planning your new construction, you should figure in about $5 per square foot of occupied building space for acoustics and noise control and some extra just in case dollars to deal with the unexpected.

Another way to look at it is to remember that an acoustic/noise control budget for new construction should be calculated at about five percent (or maybe a bit more depending on interior finish choices and design) of the cost of construction.

Be Informed

The most effective way to avoid problems from the outset is to become informed on the options and materials you can employ. I’m not suggesting you try and become experts, but simply build a general knowledge base of your options, the materials available and what they do. In that way, you can help to guide your building construction and design team to the right answers.

Again, the use of qualified professionals in acoustics and related areas such as noise control is strongly suggested. Even if you only use them for a few days to establish the best solutions, and again to verify that they have been installed correctly it will be money well spent, and inevitably will save you much more than you spend, by avoiding expensive after the fact re-work.

Gaining Knowledge, Understanding Options

While it is impossible in anything less than book length article to cover all the possibilities the following solutions are the most commonly found and the easiest to understand and in many cases deploy.

Isolation and Noise Transmission

Author’s note: Much more detailed information on all of the methods and materials discussed below can be found on the websites of the companies listed in the reference information below and other online resources.

More than any other single issue, the problem of sound or noise being transmitted from one space to another or from the outside into the building must be properly managed at the outset.

The most cost-effective solution in a new construction situation is to use materials like those shown in pictures one to four below. The Quiet-Rock drywall type panels are considerably more effective at both controlling transmitted noise and isolating room to room noise when properly installed with the resilient material position between the layers and/or double layer with air-gap type construction.

Often forgotten but equally important is floor isolation and noise control. Even with resilient material backed carpeting the use of materials like Quiet-Floor as a part of a multi-layer floor design will substantially reduce vibration, noise and control floor-born noise transmission.

If suspended or drop-ceilings are to be used in any areas, careful consideration of the type of ceiling tile used is essential. As shown in photo five, higher density more absorbent tiles can be used and are more effective at controlling reflections from the floor or walls.

HVAC

HVAC systems are a common source of both vibration type noise and air-handling noise. Designs that employ flexible or lined ductwork, baffles and low-velocity slot diffusers and air-returns will have a major impact on controlling such noise and the interference it can create for sound system intelligibility and coverage. Consulting with an HVAC professional on these issues before installation or completion of a system design is much less expensive to implement than to deal with after the fact. Another HVAC issue often overlooked is effectively sizing the system cooling/heating capability. As a rule of thumb, whatever the congregational size used to calculate the system capacity should be augmented by at least 20-25 percent to compensate for the unexpected and to reduce the speed of fans needed to control air-handling noise. A larger system can operate at lower velocities and thus be quieter and will also produce benefit in longevity as the system is not running near its limits all the time.

Echoes, Reverberation and Other Unwanted Staff

Any room will have some degree of reverberation, echoes and other unwanted acoustic problems. To decide on what to accept and what to control you need to factor in four things:

  1. Is there going to be a pipe organ and or large choir as part of the worship program?
  2. What is the worship style in general — spoken word, or music supported?
  3. How large is the overall space?
  4. What type of seating is being used, pews, folding chairs, some combination of both, upholstered or not?

Each of these four items requires a specific acoustic solution and sometimes you have a conflict between one and another. For example, the ideal sonic signature for a worship space with choir and pipe organs is not ideal for spoken word and the reverse is also true. Thus the art of compromise becomes a necessity.

However, a few general rules can be applied. First pew cushions are not a good idea. They create a difficult-to-estimate and control acoustic absorption factor. Upholstered pews, which by the way will also meet fire and building codes, are usually a better choice since their acoustic impact is a known and calculable factor.

Controlling echoes and excess reverberation is achievable using one or a combination of the materials and methods shown in photos six through 12. Diffusion panels (photo six) can be used to break up reflections and smooth out the overall sound of a space. Absorptive or a combination of absorptive and reflective ceiling ‘clouds’ or hanging panels (photos seven and eight) can be used to manage floor to ceiling bounce, reflections and control overall reverberation time and density.

The foam-like material shown in Photos 9, 10 and 11 can be used in many different configurations to manage and control echoes, reflections and damp down excessive reverberation or bounce (slap) echoes from hard surfaces or windows.

And let’s not forget the good old standby, curtains (photo 12) — specifically, acoustically absorbent curtains that also will meet fire code can be used to control wall reflections as well as darken spaces for projection in the daytime. Large windows can be covered by motorized curtains or banners to reduce reflections as needed. As discussed in Part 1, a number of companies now offer ink-jet high resolution printed banners, fabric coverings and similar materials to make the acoustical materials serve a dual purpose both decorative and acoustic.

In Summary

HOW acoustics begins with the auditorium/sanctuary but a new building is going be to be much more than just a room with pews.

A fellowship hall may create a significant acoustic requirement. And so does the daycare/after school program. More than likely your building will include at least one group of smaller rooms and spaces, which provide for staff and activities. These are usually connected by a hard-walled, hard floor hallway, which is a significant noise producer.

Remember to consider that some offices really need quality privacy, like the worship leader, pastor, minister or equivalent. Although not often thought of, even the restrooms will need some acoustic consideration and noise control planning.

The HOW in today’s communities is serving more than just faith based needs. It is providing many services both secular and spiritual. But all this side-by-side variety in space utilization also means that sound and noise control must be a top priority.

If you have questions or concerns please don’t hesitate to reach out and ask for advice. Contact us or your local professionals. They are there to provide expertise. Use it!

Dr. Frederick Ampel

About Dr. Frederick Ampel

Dr. Frederick J. Ampel has been involved in the professional A/V industry for more than 40 years, working as a systems designer, consultant, sales and marketing professional and market researcher. He was the founding editor of Sound & Video Contractor and for SCN, as well as an editorial development consultant for Residential Systems Magazine, Live Sound International and ProSoundWeb. He holds a PhD in Acoustics and MS in Broadcasting and Electrical Engineering from Boston University and has been published by the Institute of Acoustics (UK), Acoustical Society of America, AES, NSCA, InfoComm and quoted in USA Today and The Wall Street Journal, and numerous industry publications. He volunteered with and taught for CEDIA, NSCA, InfoComm and AES. In 1991, Fred founded Technology Visions Analytics, a consultancy and market research firm, which he still runs today. Reach him via email at fred@proaudioweb.com.