BL Acoustics were engaged to design and install a simple but flexible PA system at All Saint’s Church in Stock, Essex.

The Church criteria was to bring enhancement to their services and audio clarity for the choir and congregation, plus a means of adding additional input to the service. Being a small church, this needed to be discreet but effective and not overpowering.

Control of the system was also an important requirement for the organist.

The highly reverberant space was making it difficult for services to be heard clearly and this caused operational problems for the teams.


Proposed was a small system consisting of four radio microphones, one lectern microphone and multi-media inputs. For control we provided the organist with independent volume control over the Chancel and Nave loudspeakers, a dedicated Audio Input and local Remote-Control Sensor for the Media Player all situated next to the Organist at high level.


The installation used colour co-ordinated cable, loudspeakers and antenna so as not to be intrusive when seen from floor level.

The system provided 14 independent inputs allowing the capacity to add more inputs and loudspeakers if required. The 240-Watt BOSCH Plena Amplification and TOA TZ206 20-Watt column loudspeakers provided clear sound with minimal feedback.

The DN-500CB Multi-Media Player and DN312X Input Mixer were both made by Denon.

Microphones used were Sennheiser XSW2-C11. These are not the usual vocal radio systems. The XSW2 system was developed for combined use with theatre, music and speech and so has the added flexibility of being used as mobile audio line inputs too for bands or presentation laptops etc. should the church expand.


On completion, testing, and first use, the Church and users were very happy with the system achieving exactly what was needed and more. Read our testimonial from All Saints Church below.

For more information on Public Address Systems, please click here: Public Address Systems | B L Acoustics Limited

On behalf of the All Saints’ Congregation at Stock Harvard, Essex, we wanted to thank you and your team for the outstanding Sound System which you installed in June 2021.

Your expertise and professionalism were really appreciated, and you have guided us through a difficult and challenging project with sensitivity to the needs of our worship.

On the first Sunday of use, we had many comments from the congregation who said that they were overwhelmed by the systems natural amplification of the clergy and readers’ voices.

You took care to explain how the system worked and all the controls were easy to understand and use.

We would have no hesitation in recommending you to any other parties interested in such an installation.

All Saints’ Church PCC

If you want to know more about ALL SAINTS CHURCH - PA INSTALL or if you would like a no obligation quote, please contact us.
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As incumbent maintainers and installers of the PAVA Systems at the ICC Birmingham, BL Acoustics were engaged to further upgrade the Voice Alarm systems for the newly refurbished Symphony Hall.

The specification required high-performance Music Routing for the Performance Spaces and Bars by utilising the existing sound systems where possible.

Music was routed via the Bosch Voice Alarm system using Symetrix AV Processing Controllers.

For the main Performance Space, we installed four HK Audio VORTIS 2 EN54 rated Loudspeakers providing a powerful & superb quality sound in combination with the Bosch Praesideo Voice Alarm Amplification.

Fourteen music inputs were distributed throughout Symphony Hall providing a great deal of plug and play flexibility with the Symetrix System routing any input to any output.

Input panels were constructed using the single gang MK Edge Brushed stainless panels as the standard. We would implement the use of two types of panels; one would have a single XLR input and the other a 3.5mm mini jack input.

Flexible Control

The Symetrix ARC-3 Control Panel provided simple control of each input panel/music source to multiple zones throughout the Symphony Hall Foyers and Performance Spaces.

Design Verification & Modelling

The expansion included the fitting of new bars in each of the lobby areas on Levels 3, 4, 5 and 5A, a new performance space and 2 hospitality rooms on level 5A.

As part of the project, we were commissioned to design and install voice alarm coverage to the acoustically unique space, specifically the performance area with its high open ceilings and full length glass exterior wall which presented significant challenges to intelligibility. Being integrated with the Voice Alarm system, the project specification necessitated the use of EN54 approved loudspeakers only.

Before we could commence physical works, Computer Simulated Modelling of the prime areas for new coverage needed to be carried out to give evidence of design and to plan the equipment and cabling requirements. A computer model (Catt Acoustic 9) was used to create the three-dimensional environment which was then compared in performance to the specified requirements.


The specification gave a target of band ‘G’ 0.48 STI or better for 80% of the area exceeding 85dBA.


Our model implemented surfaces that were approximated to the surface types used in the building. These would provide prolonged activity for sound in terms of reverberation. We distributed the reflective and absorptive surfaces accordingly and checked the reverberation levels were in line with what would be expected for the space.

               The Model

Our Catt model was a complete model of all areas. This enabled us to model a large number of options, should they be required. The model was run several times to see the most optimum position and direction of the speakers.


               Proposed System Performance

As stated in the specification, the system was expected to meet band G in 80% of the spaces. The most acoustically challenging space, as afore mentioned, was the performance area. Here, we specified 4 high power cabinet speakers capable of delivering the sound pressure levels and performance required to give clear coverage across the atrium.

For the Hard of Hearing

The Performance Space on Level 4 was fitted with a large 16m x 12m Seven Segment Induction Loop powered by UNIVOX Audio Systems. This was installed beneath the oak floor so as to be undetectable. An audio feed was provided to the loop from the PAVA rack BL Acoustics were installing in Hall 2. This would enable both audios from the Performance Space systems and from the Emergency PAVA to be transmitted onto the loop.


The installation exceeded the clients’ expectations and offered a massive cost saving by utilising much of the already existing amplification and loudspeakers.