Koli National Park - Winter

Information

Description: 
Impulse Responses measured in the forest of Koli National Park in Finland during winter. The ground was covered in snow between 50 cm and 70 cm. Impulse responses were captured at four sites and were measured using a B-format Soundfield microphone. For each site 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).
Measurement Team: 
Andrew Chadwick
Simon Shelley
Capture Date: 
Thu, 28/03/2013
Source Sound: 
Swept Sine; 22 Hz - 22 kHz ; 30 Seconds
Source Sound Category: 
Swept sine (logarithmic)
Input: 
Genelec 8130A
Microphone(s): 
Soundfield ST450 kit
Space Category: 
Open Air
Generation Type: 
Real World

Analysis

Analysis Description: 
This is the W-channel of the B-format impulse response measured at Site 1 using the four-way loudspeaker array. 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)
0.160.180.070.181.061.500.970.440.330.22

Early Decay Time EDT (seconds)
0.470.350.220.090.090.090.090.090.090.09

Definition D50
0.540.891.001.001.000.980.960.991.001.00

Clarity C50 (dB)
0.748.9438.7732.8026.4516.1614.2121.7523.0728.41

Clarity C80 (dB)
10.6518.6842.6534.9729.1919.5617.8326.0928.1535.46


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 Sound: Single directional loudspeaker
Source Receiver Distance (m): 9 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: -8.5 °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 Sound: Four-way loudspeaker array
Source Receiver Distance (m): 9 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: -8.5 °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 Sound: Single directional loudspeaker
Source Receiver Distance (m): 11 m
Source Height: 1.5 m
Receiver Height: 1.5 m


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Sound: Four-way loudspeaker array
Source Receiver Distance (m): 11 m
Source Height: 1.5 m
Receiver Height: 1.5 m


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Sound: Single directional loudspeaker
Source Receiver Distance (m): 7.2 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: -1.5 °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 Sound: Four-way loudspeaker array
Source Receiver Distance (m): 7.2 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: -1.5 °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 Sound: Single directional loudspeaker
Source Receiver Distance (m): 7.2 m
Source Height: 1.5 m
Receiver Height: 1.5 m


Sample Rate: 96 kHz
Number of Channels: 1
Bits per Sample: 24
Duration: 5 s
File Size: 1.37 MB
File Format: wav
Source Sound: Four-way loudspeaker array
Source Receiver Distance (m): 7.2 m
Source Height: 1.5 m
Receiver Height: 1.5 m

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 Sound: Single directional loudspeaker
Source Receiver Distance (m): 9 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: -8.5 °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 Sound: Four-way loudspeaker array
Source Receiver Distance (m): 9 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: -8.5 °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 Sound: Single directional loudspeaker
Source Receiver Distance (m): 11 m
Source Height: 1.5 m
Receiver Height: 1.5 m


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Sound: Four-way loudspeaker array
Source Receiver Distance (m): 11 m
Source Height: 1.5 m
Receiver Height: 1.5 m


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Sound: Single directional loudspeaker
Source Receiver Distance (m): 7.2 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: -1.5 °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 Sound: Four-way loudspeaker array
Source Receiver Distance (m): 7.2 m
Source Height: 1.5 m
Receiver Height: 1.5 m
Temperature: -1.5 °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 Sound: Single directional loudspeaker
Source Receiver Distance (m): 7.2 m
Source Height: 1.5 m
Receiver Height: 1.5 m


Sample Rate: 96 kHz
Number of Channels: 4
Bits per Sample: 24
Duration: 5 s
File Size: 5.49 MB
File Format: wav
Source Sound: Four-way loudspeaker array
Source Receiver Distance (m): 7.2 m
Source Height: 1.5 m
Receiver Height: 1.5 m

Images

Photographs and Diagrams: 
Site 1 - Microphone
Birdseye view of measurement apparatus in the forest environment, showing the four loudspeaker orientations.
Site 1 - Loudspeaker
Site 1 - Loudspeaker
Site 2 - Loudspeaker
Site 2 - Microphone
Site 3 - Nearby tree
Site 3 - Loudspeaker
Site 3 - Trees
Site 3 - Trees
Site 4 - Road
Site 4 - Measurement kit
Site 4 - Loudspeaker
Site 4 - Loudspeaker and road
Measurement gear

Location

Address: 
Koli National Park
Ylä-kolintie 39
Koli 83960
Finland
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Attribution

Attribute this work to: 
www.openairlib.net
Audio Lab, University of York
Andrew Chadwick
Simon Shelley