An answer to their prayers - Sound & Video Contractor

An answer to their prayers

Churchgoers at Baylake United Methodist yearned for intelligible sound and a hearing assistance system not plagued by the hails of passing truckers.This
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An answer to their prayers

Jul 20, 1996 12:00 PM, Pete Cosmos

Churchgoers at Baylake United Methodist yearned for intelligible sound and a hearing assistance system not plagued by the hails of passing truckers.

This is not a typical horror story of a 10-second titanium room that was saved by a pile of gear. Baylake United Methodist Church in Virginia Beach, VA, represents an audio contractor's vision of a local neighborhood sanctuary. Constructed in 1966, the church is next to the Chesapeake Bay, sitting on a spacious, tree-lined site. A close look evokes great respect for the condition of the church, maintained meticulously by R.P. Dorton, who is the 30-year-plus caretaker of the church.

The most interesting aspect of the church's sanctuary is not the cosmetics but the sound. The room itself is not dry by any standards, but rather has a warm bump in the lower midrange that is well-suited to music without adversely affecting a high-intelligibility audio design.

The previous system was 25 years old and was plagued by interference problems from CBs and military radios. The church found itself with a new choir director who wanted to reproduce a wider variety of music and to add more miscellaneous events than the church has had in the past. Older members complained that they could not hear the service and did not appreciate truck drivers from a nearby highway interrupting the Sunday morning service on the hearing assistance system.

When our company, Audio Light & Musical, was chosen to submit a proposal for a completely new audio system, we knew only a high-quality solution would be acceptable. A system with incredible presence and speech intelligibility at low volumes was desired. The design needed to incorporate complete seating coverage while operating at low levels. The system is operated just at the point to provide great fidelity without being obvious. Because the ratio of reverberant field vs. direct field is greater at lower loudspeaker volumes, the subjective fidelity of gear throughout the chain was of utmost importance in our proposal. We chose a small, central cluster for speech and a full-range stereo pair of loudspeakers used for music reproduction to meet these needs.

Because the sanctuary is only a 10-minute drive from our office, we saw a great opportunity to use this system for demonstrations with future prospective church clients. We specified this use in the contract and offered a comprehensive service agreement in exchange.

System overviewThe main front-of-house system is a three-channel design for hi-fi music reproduction, which uses a stereo pair of Renkus-Heinz SR-82/9 Complex Conic loudspeakers accompanied by their respective passive subwoofers mounted out of sight in the organ chamber. This design provides a musical plane with organ and choir emanating from the same space. Renkus-Heinz loudspeakers were specified for this installation because of their extremely high-fidelity, smooth, nonhornlike sound. The ultrawide horizontal dispersion horns, up to 150° in the SR-62H, have superb energy distribution throughout their patterns. A second plus is the compact size of the loudspeaker enclosures.

The speech portion of the system is an arrayed pair of Renkus-Heinz SR-81s in a custom-fabricated central cluster cage mounted in the ceiling on a third node of the sanctuary. The flying structure also contains two rear-facing SR-62H loudspeakers for monitoring throughout the entire platform area.

Fly splays and angles were determined in EASE, and CAD was used to determine minimum space requirements for the center structure. The structure was then custom-fab-ricated by Audio Light & Musical's president, Tom Parker. A third SR-62H was placed on a delay for intelligibility requirements at the balcony. %Alcons were specified at a mean of 3%, and frequency response was designed for ±3dB up to 8kHz.

EASE modeling at low power levels effectively simulated the nominal operating point. Although hard vertical hang angles would be expected because of the relative position of the cluster with the first row of pews, EASE helped determine that only a 38° vertical hang angle was needed. The rear-facing monitors were pitched at 32° to cover the entire platform.

The narthex is handled by a stereo pair of NHT Super Zero compact loudspeakers operating in stereo to accurately monitor the organist's preludes. Musical selections are also reproduced from DAT and CD while the congregation lingers at the end of each service. Audio distribution throughout the facility is accomplished by IMP components. High-quality wire was used overall, and proper grounding schemes were followed.

The system front endMicrophone selection is always of critical importance on any job, and this one was no exception. A pair of CAD E-100 large-diaphragm condensers were used at the pulpit and lectern areas. These microphones work nicely for this type of application because they can be mounted at the podium level away from the presenter's face. They have excellent fidelity and even off-axis response. This method of design has proved itself on previous installations by eliminating hot spots caused by the typical hypercardioid gooseneck lectern microphone. Proximity bumps do not occur because the presenter is never more than 18 inches (457 mm) from the microphone.

The wireless lavaliers also needed to be of high caliber because the minister usually walks around the center of the platform while delivering the sermon. Shure SC wireless units were chosen because the church is near a large military installation. A pair of AKG 947s are hung in a French-radio pair configuration for choir recording and light reinforcement. Another pair of condenser microphones are available for studio boom placement for children's plays and ensembles. Soloists use conventional beyer-dynamic mics.

A Mackie eight-bus console was selected for its fidelity and flexibility. The 16.8 was configured to handle a stereo mix, mono cluster, balcony delay, stereo pair in the narthex area, separate record mix, distribution feed and two balanced aux sends for the two monitor mixes from the SR-62Hs in the flying cluster. The fully parametric EQ on the Mackie's input channels eliminated the need for external equalization on the central cluster. Straight-wire connections for all of the fixed microphones were specified and implemented. Ace floor pockets provide microphone inputs at the pulpit and lectern positions, and a custom plate on the back wall provides eight additional microphone or direct-box channels. Mogami microphone cable and multichannel snake were used for all interconnection without using terminal blocks. This method of interconnection always results in an extremely low noise-floor with exceptional transient and frequency response.

Recording and outboard gearA Tascam DA-30MKII DAT machine handles the main duties of recording services and musical events while providing a source for cassette duplication on a Denon dual-well cassette. A CD player with pitch control is available for background music and music-minus playback. A Lexicon Alex provides basic reverb fill for handheld soloist microphones and recordings. An Ashly two-channel parametric balances the main stereo system. Console monitoring is accomplished by a pair of Sennheiser HD-25s with a custom two-headphone mix receptacle extending from the Mackie rear-panel outputs.

The flying monitor system is controlled by a Sabine FBX-1802 feedback eliminator. This two-channel unit has fixed and dynamic filters to provide bulletproof monitoring by the central-cluster monitors. If needed, redundant mixes are provided by Ramsa WSA-10s from a separate amp channel for close-proximity monitoring on microphone stands.

A 52-point Switchcraft patchbay configured without normalizing allows all outboard gear and the 12 spare microphone lines to be routed only when necessary. This setup further lowers the noise floor by eliminating unused inputs from being connected to the front-end of the console.

A custom front- of-house area was constructed in the balcony by removing two end pews and fabricating a counter assembly and matching hood with cover for the console. Rather than trying to match furniture to the existing wood in the sanctuary, a different approach was taken. Because audio equipment is primarily black and gray, it is suited aesthetically to a work area with a similar color scheme. In this manner, the front-of-house area is unified by the immediate surroundings.

Isolated power circuits were installed, and individual sequencing is performed with four relays for front-of-house gear and the amplifier rack in the organ chamber. All controls are covered and locked when not in use.

Amplifiers and audio distributionFour QSC amplifiers and one separate Alesis RA-100 monitor amplifier for the narthex provide power. All loudspeaker enclosures have their own dedicated amplifier, with the main stereo pair and passive subwoofers bi-wired from one MX-1500 amplifier.

Like a high-end small audiophile model, the RH Complex Conic loudspeakers are relatively inefficient because of their small size and high power-handling capability, but they work nicely with a single, moderately powered amplifier. The filter in the sub is very smooth and matched, producing a round bottom sound rather than a thump-like sound-reinforcement sub. I prefer this sound over electronic processing in a moderate SPL situation.

Audio distribution is provided throughout several offices, including the social hall, the nursery and the hallways of the education building. An unconventional system by IMP of Miami provided power for all of the distributed loudspeakers. This is not a 70 V system but rather a three-wire system in which full-bandwidth, line-level audio and a high DC current are distributed on twisted wire to individual modular amp circuits mounted on the loudspeakers themselves. The result is a system without a transformer. This is distributed audio that has headroom, power and wide bandwidth better than would be available with a 70 V system design. Several modules are available for different power requirements. Two JBL Control 1 units furnish the small social hall and dining area and are powered nicely by 10 W modules. 20 W modules were also mounted in a wall box with a line-level volume control to enable the Ramsa 10s from the sanctuary system to be brought outside for cookouts and other outdoor activities. The existing AT&T system provides a telephone page feed.

The IMP system's line-level distributed design was also useful in adding a local mixer in the social hall. The social hall acts as a separate zone for the purpose of local podium microphone CD inputs. Additional IMP components and zones will be installed after the new social hall and choir wing are finished.

The system in useThe system was observed carefully during the first few services. Balancing was performed, and responses from the congregation were encouraged. The hearing assistance system has not been connected because great speech intelligibility is evident in even the farthest rows of pews. The audio distribution system is appreciated by the members who have other duties to perform away from the church, such as tending children in the nursery during one of the two services on a typical Sunday morning.

As a result, the overall system has proved itself to be a success for Audio Light & Musical. And for that, we are able to show our clients an impressive sound system in an equally impressive church setting.

Equipment listConsole and outboard gear1 Mackie Designs 16.8 with meter bridge1 Tascam DA30MKII DAT machine1 Denon DN-770R cassette deck1 Denon DN-600 CD player1 Lexicon Alex1 Ashly PQ-572 two-channel parametric EQ1 Atlas SACR-191 sequencer1 Sabine FBX-1802 two-channel feedback eliminator1 Switchcraft 2600 series patchbayMicrophones2 CAD E-100 large-diaphragm condenser mics2 AKG C-947 overhead condenser mics2 Shure SC wireless systems with WL-84a cardioid lavalier2 beyerdynamic M-300TGs2 Shure SM-57s2 Audio Technica AT4031 condenser mics (ensemble stereo pair)Amplifiers2 QSC MX-700s1 QSC MX-10001 QSC MX-15001 Alesis RA-100Loudspeakers2 Renkus-Heinz SR-82/9 Complex Conic loudspeakers (stereo pair)3 Renkus-Heinz SR-62H Complex Conic loudspeakers (rear-facing monitors, balcony)2 Renkus-Heinz SR-81/12 Complex Conic loudspeakers (speech, center cluster)2 Renkus-Heinz BPS 12-1 passive subwoofers (stereo pair)2 NHT Super Zeros (narthex)2 Ramsa WSA-10s2 JBL Control 1 loudspeakersRacks, interconnectsRaxcess locking steel racksMogami wireSwitchcraft connectorsAudio distribution1 IMP modular line-level distributed system controller1 MM5 pre-amp/mixer with phone interface1 MC3 mixer/pre-amp1 JVC XLV-161 CD player

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