St Andrew's Church

Information

Description: 
St Andrew’s Church, built in the 14th Century, has one of the finest examples of in-situ acoustic jars (vases or pots) in the UK. These jars were common to European church construction in the late Middle Ages and are said to be based on the ideas of Roman architect Vitruvius, who discussed the use of resonant jars in the design of amphitheatres to provide clarity of voice presentation. They are designed as Helmholtz resonators, giving narrow band energy absorption according to the natural frequency of the jar although there is little conclusive acoustical evidence to show that they behave as designed. Studies suggest that the success or otherwise of these devices depends on the number of jars used and their placement, as well as the characteristics of the building and jars themselves. In anechoic and reverberant chambers the absorption effects of such jars are weak and highly selective, although can be significant below 200Hz. Together with their additional diffusive effects, the jars potentially help to eliminate strong normal modes and hence can be made effective with careful tuning and positioning. St Andrew’s Church has 11 jars placed high in the chancel, 6 in the north wall and 5 in the south, arranged at irregular intervals such that there are no directly opposite pairs.
Measurement Team: 
Damian T. Murphy
Capture Date: 
Thu, 16/12/2004
Size: 
2600 m³
Source Sound: 
Log. Swept Sine; 20-22k Hz; 15s long
Source Sound Category: 
Swept sine (logarithmic)
Space Category: 
Church
Generation Type: 
Real World

Analysis

Demonstration Impulse Response: 

Waveform

impulseClick here or on the waveform to upload a sound from your computer and hear it in this space

Acoustic Parameters


Octave Band
31.25 Hz62.5 Hz125 Hz250 Hz500 Hz1 kHz2 kHz4 kHz8 kHz16 kHz

Reverberation Time RT60 T30 (seconds)
1.922.351.421.251.221.451.421.220.850.55

Early Decay Time EDT (seconds)
1.571.311.051.050.931.050.800.670.290.16

Definition D50
0.090.630.680.610.640.730.790.850.930.98

Clarity C50 (dB)
-10.252.223.271.942.424.305.697.5111.2916.67

Clarity C80 (dB)
-2.383.995.424.585.005.906.958.9712.9919.58


Example Audio



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Impulse Responses

Format(s): 
Stereo (Stereo Files)
B-Format (4 Channel Files)
Stereo: 

Sample Rate: 48 kHz
Number of Channels: 2
Bits per Sample: 32
Duration: 2 s
File Size: 750.04 KB
File Format: wav
Source Sound: Genelec S30D, 15 second log. sine sweep
Microphone: Neumann KM 140 Cardioid
Source Location: Centre of altar steps, chancel
Microphone Location: Centre of nave
Source Receiver Distance (m): 11.5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 13 °C

B-Format: Multichannel: 

Sample Rate: 48 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 2 s
File Size: 1.1 MB
File Format: wav
Source Sound: Genelec S30D, 15 second log. sine sweep
Microphone: Soundfield SPS422B Microphone
Source Location: Centre of altar steps, chancel
Microphone Location: Centre of nave
Source Receiver Distance (m): 11.5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 13 °C

Images

Photographs and Diagrams: 
St Andrew's Church
St Andrew's Church
St Andrew's Church
St Andrew's Church

Location

Address: 
St Andrews Church Lyddington
United Kingdom
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Attribution

Attribute this work to: 
www.openairlib.net
Audiolab, University of York
Damian T. Murphy