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VRAS Provides Acoustical Solution - In The Electronic Domain - At Church Of The Living Word
By Rick Holbrook
Church of the Living Word, located in North Hills, CA, is the first church in the U.S. to utilize with LCS Audio's proprietary VRAS (Variable Room Acoustics System).
VRAS is a hardware/software system that adds early reflections and reverberation to the existing acoustics of a space, allowing operators to match the room's acoustics to the program material at the touch of a button. LCS also claims that VRAS for this application cost less than attempting to variable acoustics using architectural treatments.
Built in the 1960s, the 400-seat church underwent a complete sound system renovation three years ago, deadening the space for the benefit of spoken word at the expense of musical programming before re-addressing the acoustical situation with VRAS.
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A perspective from the back
of the room, including a view of the loudspeakers.
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The space also sees use as the adjoining school's multi-purpose room where everything from recitals to dances to Christian rock shows occurs. Veteran audio system designer and installer Rick Holbrook spearheaded the renovation that brought the room down to a "parched" 0.9 seconds RT60.
"It's impossible to design 'perfect' acoustics even in new facilities," noted Holbrook. "The big question is 'perfect for what?' The 'perfect' acoustics for spoken word, classical music, and contemporary music are all mutually exclusive.
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Consequently, designers must compromise. In the case of Church of the Living Word, parishioners had suffered intelligibility problems in the past so church officials put a premium on clarity. Fortunately for them, two years after the renovation LCS Audio came onto the scene with VRAS.”
After going with the "bone dry" solution three years ago, church members had a feeling something was missing. Their suspicions were confirmed when a number of them traveled to Israel. They worshipped in a reverberant synagogue and were amazed by the cohesion, beauty, and emotional power of a cappella voices. Convinced that their experience in Israel was "what they wanted at their place of worship", the more musical oriented church members pressed the church to modify their existing space. Faced again with the original trade-off, church officials contacted Holbrook a second time and asked his advice. He suggested the VRAS system.
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From the front platform,
looking back, at the acoustically “dry” sanctuary.
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Essentially, VRAS couples the existing space to a second "virtual" space. To VRAS, the resulting acoustics are a mathematical interplay between the two spaces, but to the user the resulting acoustics are simply defined by the VRAS interface and easily adjusted in terms of reverb time and tone.
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With no spikes or dips across the audio spectrum, VRAS's patented unitary reverberation design mitigates feedback and unsavory coloration. Users can either enhance a room using the whole space as input (e.g. for classical music, congregational singing, etc.) or using only the stage as input (e.g. for rock music). In either case, VRAS contains unlimited cue-able presets and powerful mixing-matrixing automation to facilitate use by audio professionals and neophytes alike.
Holbrook configured VRAS with two degrees of control: a simple one for volunteers to use during services and a second one with broader control, for sound engineers to use during concerts. This is done via an AMX touch screen control panel with the default view always ready for services. This view provides three buttons, allowing a volunteer to turn off all the reverb and maintain high intelligibility during spoken word segments, or to hit the reverb setting Holbrook pre-configured for worship (1.8 RT60) to inject the power first heard at the Israeli synagogue. To provide an inconspicuous change from "dry" to "wet", the third setting functions as a halfway point - it transitions the system down to 1.3 RT60 at -4dB.
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Charting reverb at the church with VRAS (click image
for full size).
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For comparison, a nearby church was considering using heavy drapes as an acoustical treatment. Initial costs came in at approximately double the cost of Church of the Living Word's VRAS system. In addition, the drape treatment only varied the acoustics from 1.4 RT60 to 1.7 RT60 against VRAS's range of 0.9 RT60 to 3.5 RT60 (Church of the Living Word uses the latter time to deliver spectacular organ recitals).
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The church using the drape system must pick a reverberation time from its small range for a given event and stick with it; moving the drapes during a service would be too noisy and distracting.
For more knowledgeable operators, Holbrook configured VRAS to allow access to reverberation times and equalization. Eight settings on the second touch screen view allow the user to select a starting point such as "piano recital", "classical concert", "jazz ensemble", "choral concert", and so on.
From there, the operator can tweak the reverberation time and adjust the characteristics of the reverberation tail to turn the church into a dark cathedral or a soft concert hall (or just a church with more lively acoustics than the "pre-VRAS" Church of the Living Word). Because of its improved and tailorable acoustical signature, the church is hosting classical and choral concerts for the first time.
VRAS is the “brain” of an extended system of microphones, amplifiers, and loudspeakers. At the head of the signal chain are 12 Audix ADX-70 boundary microphones and four Countryman EMW hyper-cardioid microphones. The microphones feed into two Aphex 1788 remote controllable eight-channel microphone preamplifiers that in turn feed two LCS Matrix3 LX-300 frames.
The LX-300s are a modular DSP engine that performs the calculations that take microphone inputs and transform them into reverberant speaker outputs. Miles Technology MPR-450X six-channel amplifiers boost the output signals before they travel to forty-two speakers arranged strategically around the room.
Owing to a wealth of acoustically and aesthetically desirable places to hide the forty-two speakers, installation was easy. The speakers are a collection of NHT SuperOnes and SuperZeros. Holbrook recessed twenty-two speakers into a lighting soffit face-up so that they bounce off the A-Frame ceiling.
Four U-shaped beams traverse the ceiling, concealing eight more speakers in similar face-up orientation. Eight more speakers hide behind speaker grille cloth in the organ chamber above the front platform, and the remaining four speakers are hidden in the rear organ chamber.
Spoken word intelligibility remains very good, while worship and musical performances have taken on added depth.
VRAS Equipment List/Signal Flow At Church of the Living Word
12 Audix ADX-70 cardioid boundary microphones
4 Countryman EMW hyper-cardioid microphones
2 Aphex 1788 remote controllable microphone preamplifiers (8 channels each)
2 LCS SuperNova LD-88s
4 Miles Technology MPR-450X 6-channel amplifiers
42 NHT Speakers, SuperOnes & SuperZeros
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