Researchers can use the tools to analyse the emotion in respondents’ voices within their audio data.

Phebi’s machine learning software allows survey participants to respond using their voices and is also used to assess sentiment in spoken responses.

The ‘Emotion Tracker’ display charts the ‘shape of respondents’ voices, the ‘Audio Explorer’ tool pulls out specific keywords and phrases, and a third word cloud service highlights the words used most frequently by respondents.

Konstantin Morjan, co-founder and chief technology officer, Phebi, said: “With our new visualisation tools, researchers can see, play with, sort, dissect and analyse emotion data in new ways.”