In Forensic Speaker Comparison (FSC) several different parameters are commonly analysed. In this investigation we propose a multiparametric system combining long-term features (F0, voice quality and durational aspects) with short-term features (MFCCs), used by a standard automatic system based on i-vector/PLDA approaches (baseline system). The objective was to determine if the performance of the new FSC system is better than that of the baseline system. For this, three experimental designs were carried out -allowing us to evaluate the new multiparametric system in extreme conditions, as if it was a stress test-: (1) use of forensically-realistic characteristics (e.g. background noise, reverberation, intra-speaker variability, signal compression); (2) voice comparison of 12 monozygotic twin pairs; and (3) comparison of disguised voices through nose pinching. The results show that the new system performs better than the baseline system although the mean contribution of long-term features to the new system was 6.5%, with the short-term features being responsible for the remaining 93.5%.