St Mary’s Marylebone Acoustics
St Mary’s Marylebone is a busy city centre church just off London’s Oxford Street. The church venue is a stunning Grade 1 listed Georgian building that has been extensively restored.
Like many old church buildings, St Mary’s is aesthetically beautiful but acoustically challenging. As part of ongoing AV investments SFL were contracted to provide acoustic consultancy and treatment in order to transform St Mary’s from a difficult and echoey acoustic space to one that is both musically exciting and vocally engaging.
Why care about acoustics?
Building acoustics is the most foundational element of audio quality; even with the finest sound system in the world you will struggle to deliver audio quality in the wrong acoustic environment.
When considering venue acoustics, the main element we look at is reverberation time; in simple terms, the amount of time it takes after a sound has been made for it to effectively fade into the background. In particular we look at a value called Tmf, which is the average reverberation time of the mid-band frequencies 500Hz-2kHz.
Short reverberation times are brilliant for clear speech intelligibility, but make a musical environment feel ‘lifeless’. In churches this is a particularly important consideration where congregational participation in worship is a core activity. Too long a reverberation time results in an echoey, cave-like environment where speech is unclear and music feels uncomfortably ‘loud’.
So where’s the middle ground?
Based upon SFL’s extensive work in churches we believe that the ideal target for reverberation time (Tmf) in this type of venue is around 1.5s, with an allowance for slightly longer reverberation times (1.6s for example) in particularly large venues like St Mary’s Marylebone. This produces a pleasing balance between speech intelligibility during teaching and presentations, and musical excitment during worship or performance.
SFL’s Acoustic Consultancy
SFL have developed our acoustic consultancy services to compliment our specialism as an audio-visual installer.
Technical Director, Mark Payne, comments:
SFL have always pursued excellence in everything we do. We realised that designing and installing the highest quality sound systems alone wasn’t enough to complete the audio experience for our customers; the foundation for audio quality is acoustics. Over a number of years we have been developing our in-house acoustic consultation services so that we are uniquely placed to offer a holistic service to our customers on every level.
SFL first visited St Mary’s to measure the existing reverberation time, establishing the baseline from which to develop our solution. We do this by taking impulse response measurements of the venue using a gun shot from a starter pistol as the source, we then analyse these recordings using SMAART Impulse software.
Before SFL’s installation of acoustic treatment the reverberation time at St Mary’s was simply far too high, with a Tmf of 2.6s. SFL designed a treatment solution using custom manufactured acoustic panels. These were colour matched to the venue’s existing paint scheme and distributed subtly around the walls and ceiling to cover approximately 150m2 of surface, dramatically increasing the acoustic absorption of the building without imposing on its strong visual appeal.
After SFL’s installation the reverberation time dropped to an ideal Tmf of 1.6s, a drop of an entire second and perfect for this venue.
Could acoustic consultancy help your venue?
Do you have trouble with acoustics in your venue? Often acoustic treatment can deliver greater and more economical gains than investment in technical solutions that don’t address the underlying physical issues. We believe in the value of high quality sound equipment, but this value can only be realised based upon the foundation of a great venue acoustic.