The Phonetics laboratory includes an unique facility for recording breathing in multiparty conversations. Most recordings involve two or three participants, and we typically record audio, video and respiratory activity simultaneously from all participants. These facilities are primarily used in the Swedish Research Council project Breathing in conversation lead by Dr Marcin Włodarczak and Professor Mattias Heldner, but they are also regularly used by researchers from Tartu University as well as from Karolinska Institutet.

For the breathing registrations, we are using a technique called Respiratory Inductance Plethysmography (RIP). This technique measures the movements resulting from inhalations and exhalations by means of elastic transducer belts worn around the chest and the abdomen. The belts are connected to a RespTrack processor (developed in-house) that transforms the respiratory movements into direct voltages in the range −2V to +2V. These analogue signals are captured by an integrated physiological data acquisition system (PowerLab hardware and LabChart software by ADInstruments). The respiratory volumes and flows can be calibrated in liters by means of a digital spirometer (CareFusion MicroLoop) if needed. Audio is collected using head-worn microphones with a cardioid polar pattern (Sennheiser HSP 4), an audio interface (Motu 8M), and a digital audio workstation (Reaper). Video of each speaker’s head and torso is recorded using GoPro Hero3+ cameras.

Parameters of the breathing cycles, such as the durations, slopes and amplitudes of inhalations and exhalations, are extracted automatically. In the Breathing in conversation project, these parameters are related to turn-taking events derived from speech activity detection of the individual participants. For further details and publications, see our ResearchGate project page at https://www.researchgate.net/project/Breathing-in-conversation.