A Story of Excellent Sound

SFL were first asked to look at the main part of the church at HTB back in 2006. There was a level of dissatisfaction with the state of the sound system which had “evolved” over the years with no particular design ethos.

Following a full site survey SFL  found a mismatch of JBL, ElectroVoice and Community speakers with Wembley PA subs driven by an assortment of amplifiers and processors!

Tim Hughes was not long joining HTB as Director of Worship and in general the church were looking to “raise the bar” with strong contemporary worship running alongside the more traditional music forms. The sound system in place did “make noise” and made it everywhere (!) but it was hardly representative of the excellent art and heart of the musicians and congregation alike.

Acoustics

We looked at the acoustics of the HTB space first as the venue ambience and diffusion characteristic becomes the platform on which quality sound is built. HTB was a little too reverberant (a mid frequency RT of around 2 Seconds) to make contemporary music sound “tight”. The space is however well diffused due to the obvious (and beautiful) architectural complexity of the building.

Faculty

Any changes to the fittings and fabric of a traditional church space have to first seek faculty approval in partnership with the DAC. As part of the design SFL were required to provide details on the look and fitting details of the new speakers. More details on faculty approval the work of DAC can be found HERE

Computer MODELLING

Bringing together years of experience of understanding speaker system choice and placement informed by countless events, installations and venue exposure SFL also implemented EASE modelling software for SPL (sound pressure levels), making sure there is sufficient system headroom at all frequencies for the music genre in question.

The goal is to provide sound field coverage to achieve a balanced distribution of sound energy in the venue. I want all members of an audience (in this case the congregation) to have the same aural experience.

Sound System Choice

As the pictures show below, the system was designed around the use of the d&b audiotechnik Qi7 speakers as the main providers of sound energy into the open centre of the downstairs level with further Qi7 mounted up high for the left and right balconies.

d&b Q-SUB have been hidden under the stage and also mounted high and “out of the way” near and above the upper balcony Qi7 to keep the bass warmth on the second floor.

The under balcony areas on the ground floor have been kept in coverage with a distributed array of d&b Ci80 speakers pretty much on every pillar. This keeps the detail in the audio under the balcony shadow and also makes up for the further acoustic shadowing caused by the pillars themselves.

Ci80 has also been used as fill speakers on the upper level to ensure even coverage throughout the side and rear balconies on the second floor.

TIME ALINEMENT

When you use so many speakers in a distribution it is critical to use good time alignment taking advantage of the Haas Effect (rule of precedence) to “remove” the fill speakers from the perception of the listener. The focus of sound at HTB remains on the altar. Each speaker needing different time delay is driven by an individual d&b “Epac” amplifier which contains the DSP.

The setup and relative balance of the system is set by firstly using critical listening by ear, then by accurate time/space measurement using SIA Smaart Live software to perfectly time aligned of all components to a chosen reference point.

Following this successful installation SFL were asked to apply the same design principles for HTB’s sister church St Paul Onslow Square (SPOS).