Introductory Section
During the introductory section, are presented the terms, the methodology and the equipment that relate to the performance of the workshop.
The coordinator describes and gives examples for the interactions between landscape’s features (e.g. geomorphology and climate, biological and human activities, operation of infrastructures and technology) that produce sounds, as well as explains the terms of background, foreground and sound-marks for characterizing their meaning. A sound-recording device can be presented and selected recordings may be reproduced, in order to practice sound recognition from the participants.
The categorization of recognizable sounds based on their origin (from geophysical phenomena, biological or human activities and technological-machinery operation) is explained relatively to the mentioned interactions between landscape features. Prior the presentation of the thematic categorization of sounds, the coordinator may ask the participants to propose alternative thematic categories. Participants may practice by categorizing previously mentioned or played-back sounds. An empty worksheet is provided to facilitate the process.
Sound intensity is presented primary as a perceived (subjective) value. Participants are using the same worksheet to estimate a value (by assigning one number of a scale from 1 to 3) in order to quantify the perceived (subjective) intensity. Sequentially, the intensity is presented as a measurable (objective) value, by demonstrating the use of a sound-meter device and by comparing the estimated (subjective) and measured (objective) values.
Surveying Section
The aim of a field survey is the collection of data that describe the attributes of the sonic environment. Those are captured by listening, data logging, sound-recording and sound-metering. The result from a field survey is the documentation material, which will be used for the processing (at the next section).
Preparation
Although the survey may be short in duration, it requires some preparation for the formation and coordination of field-work teams, the delegation of tasks and the familiarization with the use of special equipment. Each field-work team can be composed by up to four individuals:
- one for the sound-recording device;
- another for the sound-meter device;
- one for the logging of data on the worksheet; and
- one coordinator.
In case of less individuals per field-work team, participants have to plan in advance their actions. After the delegation of tasks, participants should check the proper set-up and operation of equipment. Occasionally, the selection of the site(s) to be surveyed may be decided in advance, which requires additional time for planning. The print-ready worksheet can facilitate the organization of the field-work team, as well as the meta-data logging and pre-processing of data (prior the digital archiving).
Field Work
The process for the documentation of the sonic environment includes sound-recording, sound-metering, listening and logging data on a worksheet. During a primary investigation of the survey site, the members of the field-work team are able to familiarize with the study area, locate sonic sources and recognize sounds. Often, a field-work team could act as an intruder at a study area and trigger sound-producing interactions. It is recommended to allow some time of stillness from all members before the performance of the survey and in order to avoid biased results. In turn, this provides additional time for the preparation of a survey.
In order to combine the data from the sound-recorder, the sound-meter and the worksheet, there is a need for a common reference in time. This is the role of the team’s coordinator, who is in charge to define the allocation of equipment, to keep track of time and to tune the field-work team (as a maestro).
Sound-recording can be performed either with a dedicated system (microphones with data logger), or alternatively with any portable device (tablet or smart-phone) with adequate software for exporting sound data files. The quality of sound-recording depends on the hardware (microphone) and on the exported file format. When using a non-dedicated sound-recording device, it is suggested to set the sampling rate at 22kHz-16bit and use the WAV/PCM format for file export. During recordings, it is essential that team members remain silent and support the microphone at the height of a normal human (e.g. on a tripod).
The logging of qualitative attributes of the sonic environment is facilitated by the use of the worksheet. Before the beginning of logging, sonic sources can be located and prevailing sounds can be recognized.
Sound intensity can be measured with a calibrated sound-meter, or alternatively with a mobile device (tablet or smartphone) with an application for SPL logging and data exporting. The silence from the team members and the stability of device are the main concerns towards reliable measurements.
During a five minutes logging period the recognized sounds (occurred within every fifteen seconds) are characterized as background or foreground and a value is estimated, ranging from 1 (just heard) up to 3 (high intensity). Those values, for any recognized sound, are describing the perceived intensity and in conjunction with an abbreviation or a symbol, are assigned to each sound in order to facilitate data logging on the worksheet.
Processing Section
The processing section includes the analysis of data and the output of results followed by a discussion.
Analysis
The list of recognized sounds represents the diversity of the sonic environment whilst the summaries of values for each recognized sound, during the five minutes logging period, are expressing the impact on gained experience from each one. Moreover the number of occurrences is an index of persistence of recognized sounds.
Lower values represent rare or low impact sounds, wheres higher values indicate prevailing or high impact ones. By combining the scores of all recognized sounds it is produced a profile for the composition of the sonic environment at each site, which describes the overall sense that an individual is getting from the sonic environment at a selected site.
The characterization of recognized sounds, based on their meaning for a listener, allows the calculation of two summaries for the perceived intensity. One for the background and a second for the foreground. The comparison between those two values is describing whether a site is mostly receiving or producing sounds. Additionally, the categorization of recognized sounds based on their origin (geophysical phenomena, biological or human activities and technological-machinery operation), allow the calculation of another set of summaries that describe the formulating factors of the sonic environment.
Qualitative information cannot be measured with an instrument and thus logged data (from a listening) may be considered subjective. On the other hand, this kind of “subjective” data can be evaluated (in comparison to the sound-recordings) and be coupled with the measured data (from a sound-meter), resulting in a data-set that documents the attributes of the sonic environment.
Results
A sonic environment can be described in many ways. Keynote texts, technical reports, graphs or charts are some evident ones, from a mainly “scientific” approach. Story telling, sonic or visual compositions and performances are providing some audience-oriented alternatives, from a more “artistic” approach. Cartography is originating from and targeting to both of those approaches. Thus, thematic maps are becoming the medium of common understanding for the representation of qualitative or quantitative attributes of the sonic environment.
Processed data is used for the attribution of points that are displaying the locations of the selected sites. This operation results in the definition of a geographic feature. That is, each site can be represented as a point in the cartographic canvas. Although a graph allows the comparison of the attribute values between the selected sites, a cartographic representation displays the spatial distribution of those values over a study area.
Based on the values that are describing the attributes at each selected site, thematic mapping techniques are applied for the cartographic representation of the sonic environment. Heat map is a thematic representation that is used for the visualization of the intensity of an event within a given range. Interpolation is used for the calculation of values at intermediate points between sites with known values. This technique results in the mapping of the variability of an attribute, over an area of interest an is represented either with a color range or with contour lines.
Discussion
At the final part of the training, after the processing section and the presentation of results, follows the review of the workshop and a discussion with the participants.
- Background
- Overview
- Guidelines
- Summary