Innocent Railway Tunnel

Information

Description: 
The innocent railway tunnel, or St Leonards Tunnel, is found just South East of the centre of Edinburgh, close to Arthur's Seat. It was built in 1831, and designed to accommodate two railway tracks. It is 517 m long and straight, with a semicircular cross-section that is 6 m wide and 4.5 m high. The tunnel was closed in 1968 when this section of the railway was dismantled. In 1981 it was reopened as a footpath and later a tarmac surface was applied the floor of the tunnel. It now is also used as a cycle path and is part of the national cycling network. The first measurement, labelled "middle", was made roughly in the middle of the tunnel, with a distance of 10 m between the loudspeaker and the microphone. A second set of impulse responses was then measured at the South East entrance of the tunnel, at 6 different positions relative to entrance - labelled "entrance" (a), (b), (c), (d), (e) and (f). For the second set the distance between the loudspeaker and microphone was 5 m. The transducer positions for each measurement are illustrated by the diagrams found in the "Images" tab. For each measurement there are two sets of impulse responses: One is made with a single directional sound source (IR-1), and the other is made with an array of four directional sound sources pointing in different directions in an attempt to better approximate an omni-directional source (IR-2). The impulse responses recorded near the tunnel entrance have been normalised with respect to each other, so that the relative sound levels between measurements has been preserved.
Measurement Team: 
Andrew Chadwick
Simon Shelley
Capture Date: 
Wed, 28/08/2013
Size: 
13000 m³
Source Sound: 
Swept Sine; 22 Hz - 22 kHz ; 15 Seconds
Source Sound Category: 
Swept sine (logarithmic)
Input: 
Genelec 8130A
Microphone(s): 
Soundfield ST450 kit
Generation Type: 
Real World

Analysis

Analysis Description: 
This is the W-channel of the B-format impulse response measured at position f using a single loudspeaker. The file has been truncated and processed by fading out the signal when the reverb tail reaches the noise floor.
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)
5.284.885.354.883.722.821.961.310.890.48

Early Decay Time EDT (seconds)
0.944.263.622.861.581.190.680.300.300.17

Definition D50
0.380.350.370.310.480.570.820.940.920.98

Clarity C50 (dB)
-2.10-2.76-2.22-3.55-0.301.266.6612.1010.4016.91

Clarity C80 (dB)
5.18-0.86-0.871.013.164.308.4214.3913.9521.14


Example Audio



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Impulse Responses

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

Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Receiver Distance (m): 10 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Receiver Distance (m): 10 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C

B-Format: Multichannel: 

Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Receiver Distance (m): 10 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Receiver Distance (m): 10 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Receiver Distance (m): 5 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: 17 °C

Images

Photographs and Diagrams: 
Innocent Railway Tunnel
Diagram illustrating position of tranducers with respect to the tunnel Cross Section.
Diagram illustrating the positions of tranducers for each of the 6 measurements at the tunnel entrance.
Microphone in the middle of the tunnel
Loudspeaker set up in the middle of the tunnel
Innocent Railway Tunnel
Tunnel entrance at the South Eastern end
Innocent Railway Tunnel
Innocent Railway Tunnel
Innocent Railway Tunnel
Andrew at tunnel entrance
Simon at tunnel entrance
Innocent Railway Tunnel
Innocent Railway Tunnel
Innocent Railway Tunnel
Innocent Railway Tunnel
Innocent Railway Tunnel

Location

Address: 
The Innocent Railway Tunnel Edinburgh
United Kingdom
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Attribution

Attribute this work to: 
www.openairlib.net