This article describes the measurement and rotational analysis of several overtone vibrational bands of (HCCH)-C-13-C-13 in the region between 12100 cm(-1) and 12265 cm(-1) using cavity ringdown spectroscopy. The recorded spectra contain three perpendicular bands and one parallel band. We present rotational parameters and vibrational term values for seven different vibrational states. In the experimental technique employed, the laser source is frequency stabilised to a transmission maximum of a high-finesse ringdown cavity. After each exponential decay, the laser re-acquires the lock and maintains it until the next ringdown is commenced. Some improvements have been made to the initial version of the experimental setup and these are discussed. (c) 2006 Elsevier B.V. All rights reserved.