Feature: Creating new standards
Feature: Creating new standards
Richard Lawn visits Kuala Lumpur’s National Mosque where the open areas and terrace were plagued by poor intelligibility
Regarded as a specialist for enhancing audio intelligibility in Malaysian Mosques, Acousticon Sdn Bhd continues to adopt an analytical approach when mitigating the effects of reverberance. In its 10 years of operation, its status has been further elevated having successfully integrated a user-friendly AES67 protocol network into Kuala Lumper’s National Mosque.
With a capacity for 10,000 worshippers, the National Mosque of Malaysia (Masjid Negara Malaysia) is situated among 13 acres (53,000m2) of gardens, pools and fountains. Constructed between 1963 and 1965, the mosque is a bold and modern approach to reinforced concrete, symbolic of the aspirations of a then newly independent Malaysia. Its key architectural features are a 73m-high minaret with a folded cap and a 16-pointed star roof. Synonymous with the tropics, the main concrete roof is reminiscent of an open umbrella, for which folded plates create larger spans required in the main gathering hall.
Following major renovations in 1987, the heritage status site is once again being upgraded in phases. As such, Acousticon’s founder Azizi Bin Ala was called to site over an eight-month period to solve the inherent audio problems. ‘The overriding problem with mosques is that they are highly reverberant spaces,’ comments Bin Ala. ‘Although the dome is always seen as the main challenge, the building surfaces are hard, the prayer areas are expansive and there are many pillars.’
Phase one of the upgrade incorporates the outer areas including the 48 pillars outside the main entrance. Determined not to leave any stone unturned, Bin Ala undertook tests and measurements to determine the directivity, background noise, frequency response, distortion, RT60, SPL signal-to-noise and STI readings in addition to acoustic measurements. ‘For the electro-acoustic assessment, we use NTI Audio products including an XL2 Acoustic Analyser set, Talkbox and a DS2 Dodecahedron speaker set. Once all the data had been collated, I submitted an analytic report, which formed the base for an assessment and a proposal using EASE 4.3 modelling.’
With average STI readings below 0.45, the open areas and terrace were plagued by poor intelligibility. Not only had the existing column-mounted speakers been malfunctioning because of damaged high-frequency drivers and power supplies, they had also been installed wrongly. ‘To achieve the 32m throw required, the existing steerable speaker height from the floor needed to be 4.5m. In addition, set delays and time alignments were inaccurate and the 48-column pillar zone was plagued with problems.’
The existing audio system and acoustics were not exclusive challenges. ‘Prior to prayers and recitals, the nine imams and nine bilals all needed a competent technician to manually operate the PA,’ furthers Bin Ala. ‘Naturally, this led to human errors at times. The analogue audio system also lacked processing features for system tuning and matrix routing in addition to a power conditioner and sequencer.’
Being a heritage listed building, the audio designs needed to be sympathetic to the façade and its architecture. ‘Modifying columns and interior designs was out of the question, so a discreet solution was paramount,’ furthers Bin Ali. ‘In addition, the design had to be created with a limited budget.
With the Iconyx and IC Live being the speakers of choice for Mecca, Renkus-Heinz was the favoured brand for the National Mosque. In addition to selecting its column speakers for the project, Bin Ali also welcomed the opportunity to work with Renkus-Heinz’s distributor, Mercoms Systems. ‘I’ve always enjoyed working with Steven Chan and his team as they offer us great support with the designs.’
In total, 24 ICX7-II mechanically steerable line arrays have been sensitively affixed in pairs to 12 columns throughout the outer areas. Each ICX7-II comprises four LF 4-inch woofers and three 4-inch coaxial transducers with triple 1-inch tweeters, while the internal passive electronics control the frequency and phase response of each driver to create a uniform 30° beam. The pairing of two 13.4kg enclosures creates a tighter beam control of 15° while adding an additional 6dB in output. Aesthetically, the slim black matt enclosures blend in with the mosque’s vertical columns, bypassing the requirement to adjust further to the architecture.
‘The ICX7 provides an even 120° horizontal dispersion in the 48-column zone and has sufficient throw without any loss in dB,’ furthers Bin Ala. ‘By adopting the standard Renkus-Heinz mounting solution together with a customised bracket, we fulfilled the interior design objectives.’ Owing to budgetary constraints, Acousticon was forced to slightly modify the design. ‘We re-engineered the schematics by simplifying it from a distribution solution with multiple speaker locations to a centralised solution with single locations in stackable speaker configurations.’
Until recently, all mosque audio operations in Malaysia have operated in the analogue domain, but Bin Ala is attempting to upgrade all the mosques he serves with digital solutions. ‘I love the analogue sound but, unfortunately, so many users are inquisitive and want to play around with the settings. Over time, this leads to a degradation of sound, as the system is not reset.
‘Central to the DSP solution in the National Mosque is a user-friendly interface,’ he continues, highlighting the 12-inch iPad Pro integrated at eye level at the top of the rack. ‘I generally propose the Q-Sys platform for larger mosques with a simplistic touchpanel concept using Q-Sys iPad control. The GUI can be fully customised to a mosque’s particular needs with zoning capabilities built in. With this digital solution and the pre-set features integrated into it, settings can be returned to traditional settings.’
The intuitive GUI displays icons for all nine imams and nine bilals, for whom Bin Ala prepared individual settings. Once the technician has clicked on the icon of the selected imam or bilal, he can then select a combination of the seven zones for broadcast, adjust the level and play. Of the eight months that Acousticon spent working on the project, this centrepiece took just one week. ‘Q-Sys programming is straightforward, but it took me some time to photoshop the 18 images and create the exact presets.’
The panel is triggered within the control room and then activated externally. ‘Consequently, the vocal tones of the imams and bilals are naturally crisp and crystal clear. The imamss can be quite particular about how they sound, so I had to adjust the dB levels for all of them.’ In addition to the Shure BLX wireless system and wired SM35 microphone transmitters that are input to Attero Tech AES67 receptacle panels, a CD player can also be selected as a source.
Imam Afif agrees. ‘It’s so easy to use – I simply click on my icon and know that my voice has been improvised and optimised with the correct tonal clarity. On my first use when I recited the Koran, the verses of citation were crystal clear. As a result, the worshippers are totally attentive now and understand my readings.’
Feeding the delayed ICX7-II outputs, a combination of five QSC CXD4.2Q and 4.3Q amplifiers receive the audio signal from a Q-Sys 110f Core processor over a Cat-6 network. ‘Dante was cost-prohibitive, so we simply promoted the AES67 open protocol. The digital AES67 solution uses a network switch to connect all the equipment, including the microphone panels, rack devices and steerable speakers over the Cat-6 network we installed.’
With the National Mosque, Acousticon believes that it has created the new standard for Malaysian houses of worship. ‘In future, mosques may need to be monitored for highlighting fault detections or if a user forgets to plug in a microphone. The current status of a system can be controlled, while alerts can be triggered and SMS texts and emails sent to remote engineers when a fault is detected. This is a great monitoring system for all mosques but, to allow for a service department in the mosque, you need an internet connection and that is not always available.’
Four TOA DH-120 long-throw horn speakers installed into the main minaret constitutes as one of the seven zones. Following successful tuning and programming using Smaart v8.0 software, Acousticon’s eight-month tenure onsite was at an end. And with an STI reading boasting up to 0.59 with an average of 0.56 in the terraces and open pillar area, it’s doubtful that Acousticon will be called to site until the second phase rolls out.