Metadata for Figure 1 of 'Comment on: Are some people suffering as a result of increasing mass exposure of the public to ultrasound in air?' by Timothy G. Leighton (Proceedings of the Royal Society A, 2017) Authorship: Timothy Leighton, Craig Dolder, Sarah Dennison and Michael Symmonds Microphone: PCB Model 377B02 Recording device: Fostex audio recorder System calibrated: At NPL, see (corr_freqs.mat for frequencies and PCB_corrections.mat for calibration values in dB) Sampling frequency: 96000 Hz Time of file analysed: 37.2138 s - 42.2138 s Location of recording: The computer room is approximately 10 m by 25 m by 7 m high. There were 8 speakers in the room, 4 on each side, spaced approximately 5 m apart. Measurements were taken 1 m from a speaker, at head height. Caption to the figure: Figure 1. Recordings of the acoustic field in a university computer room, at a range of 1 m away from the loudspeaker which was the presumed main source, showing (a) the spectrogram and (b) the Sound auto-spectral density. The colour scheme in (a), and the vertical axis in (b), share a common description [(dB re 20 uPa)/Hz, as shown by the arrows at the base of the figure]. Further details are given in Appendix 2 [of the Comment paper]. The significance of the broken lines is described in the text.