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Audio file processing in research

Audio file processing in research

Sound recordings can be highly personally identifiable, and the more sensitive the data is, the higher the level of security should be.

You can read more about yellow data and how they are classified here.

  • Recommended recording equipment

    Both the mobile app "Diktafon" and a physical recording device (physical dictaphone) are approved for the use of audio recordings at OsloMet, but the use is not without risk regardless of what you choose to use.

    The Dictaphone App

    OsloMet recommends using the Nettskjema-dictaphone app, made by UiO.

    Known risks using the mobile app "Diktafon"

    A mobile app is potentially more likely to fail than a physical voice recorder. OsloMet has experienced that such errors have occurred due to a mismatch between the app and the operating system on the phone, which can occur during the period when, for example, Apple or Google launch new versions. That is why it is important to test the app in advance of the recordings to be made. Especially if there have been changes to your mobile device since the last time.

    In any case, OsloMet recommends for "unique recordings" that you have a backup device. If you want to use a physical recording equipment for sound recording instead, read more below.

  • Recording equipment (physical dictaphone)

    Lending a physical dictaphone at OsloMet

    The library (P48 1st floor) lends various types of AV equipment, including physical dictaphones without a memory card (you have to buy this yourself), see website IT help and AV lending.

    Watch out for

    When handling a physical recorder, you must be aware of your behaviour:

    • Do not leave it in places where you do not have control of the recorder
    • Lock the office where it is kept
    • Do not lend the recorder to unauthorized persons, etc.

    Security when using a physical dictaphone

    None of the lending dictaphones at P48 currently have satisfactory security should the device go astray. This is because they lack a pin code and encryption.

    Recommended type of physical dictaphone

    For research groups needing a physical voice recorders in their projects, we recommend that you purchase a device that meets the requirements for PIN code and encryption (for example, Olympus DM-720 and Sony PX4700, an additional memory card of 4 GB is sufficient).

  • Reducing the personally identifiable factors in audio recordings

    In many projects, SIKT recommends instructing interviewees not to provide information that could increase the possibilities of recognition such as place names and institutions the interviewee is affiliated to. This should only be provided if it is necessary for the data material.

  • Encryption 

    A recorder can be used for several projects at the same time if it is used by one person only. However, it is recommended that recordings are transferred to an encrypted unit (memory stick, external hard disk) or that the interview is transcribed as quickly as possible, so that the recording can be deleted from the dictaphone.

    See downloading encryption software.

    Memory cards or the disk in the sound recording equipment can usually not be encrypted.

    If a recorder is used by several persons at the same time, it should only be used for one project. The recordings must be transferred to an encrypted unit and deleted from the dictaphone as soon as possible after recording. If the dictaphone is to be used in new projects, new memory sticks must be used. Old memory sticks are destroyed.

    The recorder must be stored in a lockable cabinet when not in use, see Storage of audio files below. Other encrypted storage units must also be stored in lockable cabinets.

  • Editing and transferring audio files from one storage unit to another

    Audio files with a medium/high degree of sensitivity must not be edited or stored on computers connected to the internet unless they have been anonymised according to the instructions above.

    Audio files can be edited on stationary computers and laptops that are either permanently or temporarily disconnected from the internet. "Temporarily disconnected" means that the wireless network connection is turned off or the internet cable has been pulled out. If a audio file is temporarily stored on a computer, you must ensure that it is completely deleted before you connect to the internet.

    "Permanently disconnected" means that it is not possible to connect the computer to the internet. Whether you should use a computer that is permanently or temporarily disconnected depends on how sensitive the material is. 

    You must ensure that no unauthorised persons are present in the room in which the editing takes place.

  • Deleting audio files at the end of a project

    Deletion of audio files at the end of a project. Audio recordings are taken to IT Support (BIT) to ensure that they are completely deleted.

    Data transferred to a memory card/memory stick cannot be definitely deleted. At the end of a project, these devices must therefore be destroyed, unless they are to be used by the exact same person(s).

    Memory cards/memory sticks are handed in to for destruction.

    • See the data security guidelines on deletion and destruction
    • If long-term storage of audio recordings is desirable for the purpose of conducting follow-up studies (research purposes), you must apply for approval from SIKT (and REK).
    • If audio recordings are to be used for other purposes after the end of the project, e.g. in teaching, you must apply to the Data Protection Authority
  • Storing audio files

    Audio files should be stored on an encrypted memory stick or an encrypted external hard disk. The devices should be stored in a locked archive or a cabinet with controlled access. If the cabinet is in a room that is in general use, it is recommended that a safe or a cabinet with two doors is used to make it difficult to break into it. If the cabinet is stored in a room that is not in general use, an ordinary lockable cabinet may be sufficient.

    • See the data security guidelines on storing, sending, sharing and deleting .
    • If the raw material is important, the cabinet must be fireproof and have smoke detectors and fire extinguishing equipment/a sprinkler system in the same room in order to ensure verifiability.
    • If audio recordings are stored in the office during working hours, you must lock the door when you leave it, see the data security guidelines on physical securing of OsloMets premises.
    • There should be a procedure for storing keys/key cards for doors and cabinets.
    • You should record when, who and for which purpose each time you handle the audio recordings.
    • Alternatively, audio files can be stored on Service for sensitive data (TSD 2.0) ( Contact for more information.
  • Archiving audio files

    If it is desirable to store the data for the future, audio files may be stored by SIKT. They provide a description of how the data should be prepared for archiving with, among other things, a list of preferred file formats and the relevant documentation to be enclosed, what is to be filled in and signed, and how the data should be transferred. 

  • More about audio file processing in research

  • Anonymisation of audio

    The anonymisation of audio means that all the vocal characteristics on the recordings are removed. This can be done in the following manner:

    After recording, the original audio is transferred from a voice recorder to a voice processing computer that is not connected to the internet. The audio recordings are run through a voice changer that de-identifies the voices. The audio may then be transferred to a mobile disk etc. for further processing on a computer, regardless of whether it is connected to the internet or not. Although the voice has been changed, the content of what is said can still make the person identifiable. You must therefore consider what is being said aw well.

     You should not use this method if the material is to be transcribed, and pauses, accents etc. is determinant for the interpretation of the material.

IT Service Desk

IT Service Desk