This paper describes a reference study in which the behavioural thresholds to chirp stimuli are measured in a large group of normal-hearing individuals. The test group consists of 25 young adults (N = 50 ears) and the measurements are in compliance with the recommendations given in the ISO 389-9 standard. The test signals are the CE-Chirp and the four octave-band chirps, which are presented at two repetition rates, 20 and 90 stimuli/s, and using the ER-3A insert earphone. The calibration values are reported in dB p.e. SPL in the occluded-ear simulator. The results are similar to those from another investigation (PTB-study) and the values from the two, independent studies are therefore relevant for a future extension of the existing ISO 389-6 standard, which presently provides reference calibration values for standardized click and tone-burst stimuli delivered from various earphones.