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Articles May-June 2021

Pursuing the Pro Audio Trail

In conversation with Caroline Moss and Sue Gould

PT got in touch with the Pro AVL Asia magazine core team of Editor - Caroline Moss and Sales Director - Sue Gould, who between them boast of over three decades of experience in the pro audio industry..... read more

NJSM Marks a Milestone in the Business of Sound

From Rental Company to manufacturer and innovator, Nixon Johnny has guided and grown NJSM from a two-person company to a fifty-person company, continuing to expand into virtual events with NJSM Virtual Studio..... read more

Tech Savvy Environment for T-Systems

Eyte Technologies installs high-tech AV Solution at T-System’s Experience Center facilitating brand value and delivering superior customer experience..... read more

Conversations with SudeepAudio

Sudeep Audio, one of India’s first pro audio web store selling studio software and equipment online commenced its YouTube Channel, ConverSAtions, in 2011 to share the journey of Indian Sound Engineers..... read more

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In-ceiling Speakers

Hidden Gems

In recent years, in-ceiling speakers have become a popular choice as they facilitate great audio experience without disrupting the visual aesthetics of the venue. In this guide, PALM Technology has covered some in-ceiling speakers launched in 2017-2018 with intent to provide readers with a quality guide that can help your sourcing needs.

Bose Edgemax

Bose Professional’s EdgeMax in-ceiling loudspeakers feature proprietary Bose PhaseGuide technology, which Bose says provides room-filling coverage while improving overall sound quality compared to the performance of conventional ceiling loudspeakers.

These in-ceiling premium loudspeakers are available with two different horizontal coverage patterns. EdgeMax EM90 models provide nominal 90-degree horizontal coverage and are intended for in-ceiling mounting near room corners. EdgeMax EM180 models provide nominal 180-degree horizontal coverage and are intended for in-ceiling mounting near wall boundaries centered along target coverage zones. Both models feature 75-degree asymmetrical vertical coverage, which is optimized for ceiling heights between eight feet and 20 feet..

Main Features include:

• PhaseGuide technology, which provides unique asymmetrical vertical coverage pattern designed for room-filling sound when mounted in-ceiling near wall boundaries
• 1.3-inch diaphragm compression driver for best-in-class audio quality with superior frequency response and coverage consistency versus typical dome tweeters
• Eight-inch woofer with wall-boundary loading, which provides extended bass impact
• Two-way passive crossover with 8-ohm or 70V/100V transformer taps
• New mounting-clamp system for fast, easy installs
• Magnetically attached grill for quick access to wiring and tap settings
• UL1480 listing for air-handling (plenum) space installation
• Easy installation, saving integrators time in the field.

Tech Specifications:

Single Module Performance
• Frequency Response (-3 dB): 50 - 18,000Hz
• Frequency Range (-10 dB): 45 - 20,000 Hz
• Nominal Coverage Pattern: 180° H x asym metrical 75° V (0° to 75° referenced to wall)

Bose extended-lifecycle test & AES transducer test

• Power Handling, long-term continuous: 125 W; 150 W
• Power Handling, peak: 500 W; 600 W
• Sensitivity (SPL/ 1W@1 m): 96 dB; 96 dB
• Calculated Maximum SPL @ 1 m: 117 dB; 118 dB
• Calculated Maximum SPL @ 1 m peak: 123 dB; 124 dB
• Crossover: 1.0 kHz (passive 2-way crossover with integrated 70/100V transformer)
• Loudspeaker EQ: Recommended but not required
• Recommended high-pass protection: 55 Hz with minimum 12-dB / octave filter
• Overload protection: Resistor-network power reduction with automatic reset
• Transformer taps: 70V: 2.5, 5, 10, 20, 40, 80 W, bypass / 100V: 5, 10, 20, 40, 80 W, bypass


• Low Frequency: 1x 8-inch woofer (1.5-inch voice coil)
• High Frequency: 1x compression driver (1.3-inch voice coil)
• Nominal Impedance: 8 ohms (transformer bypass)
• Enclosure Material: Engineered-plastics front baffle with integrated steel formed enclosure
• Grille: Micro perforated steel, powder-coated finish, white: RAL 9010, paintable
• Environmental: Indoor only; UL-1480A listed, in compliance with UL2043 for plenum-space installation
• Connectors: Euro block 6-pin connector with loop-through, front-baffle mounted
• Suspension / mounting: Four (4) auto-hold, spring-loaded mounting arms plus four (4) M6 safety cable tabs
• Maximum ceiling thickness: 80 mm (3.2”)
• Dimensions (H x W x D): 339 x 339 x 249 mm (13.4” L x 13.4” W x 9.8” D) enclosure; 390 x 390 x 13 mm (15.4” L x 15.4” W x 0.5” D) grille flange, as mounted
• Ceiling cutout and clearance: 345 x 345mm (13.6” L x 13.6” W) with 236 mm (9.3”) mounting depth
• Net Weight: 10.1 kg (22.2 lbs) with grille
• Shipping Weight: 12.5 kg (29 lbs)
• Accessories: Adjustable Tile Bridge (Included), Black grille, rough-in pan for new construction

Harman Professional LCT 81C/T

LCT 81C/T is a full-range ceiling speaker designed to lay into a 2 ft x 2 ft US-style suspended grid ceiling, with no cutting of ceiling tiles required, making for an easy and cost-effective installation with a minimum of mess.

This loudspeaker is designed to provide excellent performance for paging and light-to-medium music in a wide variety of applications, including education classrooms, business music systems, retail stores, music/paging systems, airports, reception/waiting rooms, lounges, courtrooms, meeting rooms, and more.

Main Features include:

• High efficiency 200 mm (8 in) dual-cone driver.
• Easy lay-in installation into 2’ x 2’ US-style suspended grid ceilings. No cutting of ceiling tiles is necessary.
• Perforated metal grille included.
• Combined 70V/100V and low impedance direct operation.
• 20 Watts at 8Ω (low-impedance) direct setting.
• 10 Watt multi-tap at 70V/100V with taps at 10W, 5W, 2.5W (and 1.3W for 70V only)
• Very low-profile at just 103 mm (4.1 in) deep, to fit into ceilings that are shallow or that contain obstructions.
• Easy bare-wire connection in protected compartment. Wire entrance from either top or side via knock-out.
• Very high 96 dB sensitivity turns power from small amplifiers into maximum sound level for listeners.
• Designed for high speech intelligibility.
• 100° coverage pattern (conical).
• UL1480A and UL2043 certifications for use in ceiling plenum spaces.

Tech Specifications:

• Transducer: High-efficiency 200 mm (8 inch) dual-cone driver with 25 mm (1 in) diameter voice coil, Kapton coil former, and high-temperature voice coil wire.
• Frequency Range (-10 dB): 100 Hz – 16 kHz
• Nominal Sensitivity: 96 dB
• Nominal Coverage Angle: 100° conical coverage (ave. 1 kHz - 4 kHz)
• Rated Maximum SPL: 108 dB @ 1 m (3.3 ft) average, 108 dB peak (at 8Ω setting)
• Nominal Impedance: 8 ohms (in Direct/Thru 8Ω setting)
• Transformer Taps: 10 W, 5 W, 2.5 W @ 70V or 100V (plus 1.3 W @ 70V only)
• Recommended Protective High Pass: 90 Hz high-pass (24 dB/oct) for 8Ω direct or any 70V or 100V tap setting
• Power Capacity (at low-Z): 40 Watts Continuous Program Power 20 Watts Continuous Pink Noise
• Input Connector: Bare wire inside protected in touch-proof wiring compartment.
• Tap Selector: Rotary switch accessible from side of backcan
• Materials: Steel rear enclosure, front baffle, and perforated grille
• Grille Color: White
• Dimensions: 607 x 607 x 103 mm (23.9 x 23.9 x 4.1 in)
• Net Weight: 7.1 kg (15.7 lbs)
• Shipping Weight: 8.3kg ea; 16.5 kg per pair-pack (18.3 lbs ea; 36.4 lbs per pair-pack)
• Ceiling Cutout Size: No cutout required. Speaker drops into ceiling grid
• Suspension / Safety-Seismic Attachment Points: Two tabs on back baffle, plus 4 holes in corners

Meyer Sound Ashby Series

The Ashby Series comprises two flush-mount models: the Ashby-5C with a 5-inch low-mid cone driver and the Ashby-8C with an 8-inch low-mid driver. Both employ a concentric 0.75” metal dome tweeter and are housed in integral, quick-mount metal backcans with Phoenix connectors for fast, simple installation in new or retrofit systems. The innovative dual-driver concentric design provides a uniform 100-degree dispersion pattern, allowing use of fewer speakers to cover a wide listening area.

Main Features include:

• Self-powered ° Easy to install
• Extremely wide and consistent coverage
• Very low distortion ° Exceptional SPL to size ratio
• Supports long cable runs with light-gauge cables
• Distributed systems for music and paging where high-quality and intelligibility are a must
• Constellation acoustic systems.

Technical Specifications of Ashby-8C:

Acoustical Ashby-8c

• Operating Frequency Range: 70 Hz – 18KHz
• Frequency Response: 80 Hz – 16 kHz ±4 dB
• Coverage: 100°


• High Frequency: 0.75” metal dome tweeter
• Low Frequency: 8” cone driver

Audio/Power Connector

• Connector: (2) Phoenix 5-pin male (two pins for DC power, three pins for balanced audio)
• Power Wiring: Pin 1: DC Power + | Pin 2: DC Power –
• Audio Wiring Pin 3: Chassis/earth | Pin 4: Signal – | Pin 5: Signal +
• Voltage Requirement: 48V DC from Meyer Sound power supply


The QSC AcousticCoverage Series AC-C4T is a ceiling mounted 4” full-range loudspeaker with 70/100V transformer, suitable for a wide variety of audio/video conferencing reinforcement, voice paging and background music applications.

A high quality 4 inch polypropylene cone transducer with butyl rubber surround offers pristine clarity through the critical vocal range for increased speech intelligibility. With 140 degrees of conical coverage, the AC-C4T reduces the number of loudspeakers required for even coverage in low ceiling applications..

Main features include:

• High quality 2.75” full-range transducer provides a natural rise in high frequency extension.
• Ported baffle for increased low frequency extension down to 70 Hz.
• Low saturation 70/100V transformers with 8 ohm bypass.
• 4 pole Euroblock connector eases system wiring.
• Advanced voicing filter sets using QSC Intrinsic Correction available through either Q-SYS processing or CXD amplifier platforms.
• White (RAL 9010) with UV inhibitors to match complimenting QSC product families.
• Complete EASE, CAD & BIM information available online.

Tech Specifications:

• Effective Frequency Range: 70 – 16 kHz
• Rated Noise Power / Voltage: 16 watts / 11.3 volts (rms)
• Broad-Band Sensitivity: 89 dB SPL
• Coverage Angle (-6 dB): 140° (500 Hz - 5 kHz)
• Maximum Continuous SPL: 101 dB
• Maximum Peak SPL: 107 dB
• Rated Bypass Impedance 8 ohms
• Transformer Taps: 70V: 16, 8, 4, 2, 1 watts and 8 ohm bypass; 100V: 16, 8, 4, 2, watts and 8 ohm bypass
• Transducer: 4” Polypropylene cone with butyl rubber surround
• Input Connector Type: Euroblock connector with parallel output terminals
• Baffle Material: Painted ABS polymer
• Grille Material: Powder coated stee
• Backcan Material: Galvanized steel
• Testing: Listed UL1480, UL2043 safe for use in air handling space
• Included Accessories: Rails & C-ring for ceiling tile installation
• Cut-Out Dimensions (Dia): 7.31” (185.67 mm)
• Ceiling Capture Thickness: 0.25” - 1.5” (6.35 - 38.1 mm)
• Dimensions (Dia x D): 8.4” (214 mm) x 7.9” (201 mm)
• Shipping Dimensions: 10.75” (273.1 mm) x 24” (609.6 mm) x 10.5” (266.7 mm)
• Net Weight: 4.9 lbs (2.22 kg)
• Shipping Weight (Pair): 15.1 lbs (6.86 kg)