The 21st Century continues to herald increasingly sophisticated electronic gadgetry, presentation systems, software and hardware platforms, and ever-evolving communication standards almost on a weekly, sometimes daily basis.
For example, both commercial and consumer sound and audio-video equipment becomes obsolete almost as soon as it hit the shelves. System designers and integrators increasingly find it necessary to withhold direct product specifications until the eleventh hour due to this very reason.
However, from a building design standpoint, what are some of the impacts presented by worship technologies (i.e., audio, video, broadcast, etc.)? In the increasing fervor to jump onto the technology bandwagon, many design teams and owners are failing to address the potential and obvious impact of such an elaborate system. These are:
• Space allocation needs
• Electronic system requirements
• System cost factors
• Room acoustics and noise control
While most mega-churches appear to be blessed with seemingly bottomless coffer based on the size of its constituents, the average American Church project is typically on a fixed, tight, and unwavering budget. This is understandable since prototypical Churches (based on national and denominational surveys) range in the neighborhood of about 125 regular members. Basically, the desire and need for up-to-date worship technologies simply translate to the bottom-line; cost.
In addition to appropriating technology related cost factors, system support spaces and design requirements affecting the overall building design parameter is essential and must be included in the initial stages of planning. Each system is accompanied with its own set of requirements, one or two projection rooms for rear screen systems and equipment rack space. In addition to the room itself and their associated construction costs, other cost elements include electrical and ventilation requirements.
For instance, many Churches are captivated with rear video projection systems since it is aesthetically pleasing, almost magical, and it obscures unsightly hardware and structural components. Yet, such systems translate to additional system costs, like image and screen size requiring long throw distances hence affecting architectural design and space allocation, projection mirrors for limited space, and the associated cost for construction, power, heating, and cooling. In addition to projection and equipment rooms, additional space requirements may include video and audio control, editing, post-production, and broadcast space.
This includes electrical load, phase, grounding, available circuits, harmonic shielding requirements, conduits, etc., which are vital to the functions and operations of the overall integrated technology. For example, audio-video system design requires dedicated clean and reliable power supply; free of harmonic distortion, ground loops, conduit and circuits sized appropriately, and with the necessary cooling and air circulation system. These are especially true in retrofit projects wherein the existing power is not sufficient in meeting additional electrical loading and would require significant upgrade costs.
Other more esoteric, yet necessary features include functionality, flexible design, ease of use, and controllability. These may be in forms of ensuring that every contingency in well thought out, conduits are sized for future expansion, junction boxes are in all conceivable locations, system consoles with enough spares for remote possibilities, and coherent and logical control systems.
In addition to obvious utility cost associated with the worship technology, the initial budget should also include cost of maintenance, equipment replacement, and hiring of qualified support personnel and technician (to include employee benefits). These are vital elements that could undermine successful implementation, quality of the end product, and operations for such electronic systems. By quality, the emphasis is on staffing technical positions with qualified key personnel and not relegating to the first “techno-geek” who willingly volunteered his/her services without due diligence to their qualification and experience for the task at hand. For most average Churches, hiring of qualified and trained personnel is simply improbable due to related costs, and the church is forced to rely heavily on the availability of someone who may be under-qualified.
Room Acoustics Design
Beyond the need for technology in worship is an understanding and appreciation for proper room acoustics design. This is an area that is commonly missed, ignored, or value engineered out of a project with obvious detriment to the performance of the worship space. Room acoustics design include the following items affecting speech intelligibility, music performance, and overall function and usability of the worship environment:
This component directly corresponds to room volume, wall, floor, and ceiling finishes affecting room response and characteristics. Reverberation is simply a unit of measurement involving the length of time for sound to diminish by 60 decibels (dB) following termination of the signal source. This plays a vital role in whether or not a space is suitable for speech, choral and instrumental music, or organ performance.
For example, worship spaces wherein the spoken word is priority and music secondary would require reverberation time ranging from 1.2 to 1.5, offering superior speech intelligibility and an acceptable music performance environment.
These are basically impulse sound energy emanating from a given sound source and reflecting or “bouncing” between two parallel wall surfaces, and is controlled via sound absorbing wall treatment typically on one available wall surface from wainscot height to door elevation. Another option would be to cant one parallel wall by minimum 7-degrees off parallel, or providing sound diffusing treatments to scatter or diffuse sound.
Flutter echoes should not be confused with basic echoes that are formed by sound arriving at the listener’s location in excess of 60 milliseconds (1/17 s) arrival of direct and reflected sound.
Initial Time Delay Gap
Simply defined as the difference between the direct sound and reflected sound paths to a listening position. The human ear uses the relationship of direct and reflected sound paths for distinguishing sound directivity, depth, envelopment, and clarity. This is especially important for sound reinforcement system design, and in music performance. For speech listening condition a time delay gap of 20 to 30 milliseconds is ideal.
Sound Absorbing Treatments
These are manufactured wall and/or ceiling finishes and products with rated sound absorbing characteristics typically expressed in NRC or Noise Reduction Coefficient. For example, a lay-in ceiling tile with NRC of 0.75 essentially means that 25% of the sound energy would be reflected back while 75% of sound energy in the 250 Hz to 2000 Hz bands hitting the panel would be converted to heat energy and thus “absorbed.”
Examples of sound absorbing materials include mineral tile ceiling, fiberglass “Nubby” ceiling tile, fabric-wrapped fiberglass wall panels, perforated metal or “Ventwood” panels with insulation backing, etc. Associated costs for these products range from $1.50/s.f. for fiberglass insulation to over $50/s.f. for exotic materials, with typical fabric-wrapped panels in the $10/s.f. range installed.
Sound Diffusing and Reflecting Elements
These are architectural elements concocted for augmenting natural room acoustics, sound projection, diffusion, and often in the form of radiused or sloped individual panels or shaped ceiling.
Building System Noise and Vibration
Factors affecting the usability and performance of worship space include the architectural design, room acoustics, worship technology systems, and mechanical or building system noise and vibration. Mechanical noise and vibration control issues should be addressed in the preliminary phases of the design and should include equipment location, type of system and equipment, sound and vibration isolation construction, and ventilation system layout. All of these factors affect residual noise within the worship space.
Basic design criteria should be established early on since this could affect architectural, mechanical, electrical, and structural design of the building, and could have an impact on budget. For example, churches should be designed for background mechanical noise level ranging from (Noise Criteria) NC-25 to NC-30. This single number unit represents the summation for all system noise sources such as mechanical fan noise, airflow noise, air turbulence, and electronic equipment noise.
Ideally, mechanical units should not be located adjacent (vertically and horizontally) to any noise sensitive areas such as the worship space, chapel, narthex, classrooms, and offices. Equipment should be placed in sound isolated mechanical rooms composed of full-height, grout-filled CMU block wall, sound isolating doors, and in some cases, sound isolating floor-ceiling construction for noise sensitive vertical adjacency.
This article is meant to expose the reader to some of the basic requirements for worship technologies and is in no way exhaustive or detailed. Churches currently in the process of procuring sound, audio-video, multimedia presentation, and broadcast technology should enlist qualified consulting services through the Inspiration Conference, NSCA, AES, and Infocomm. A list of qualified acoustical consultants is available from the NCAC, ASA, INCE, and ASHRAE.