Acoustic parameters are very useful in voice screening, diagnosis and rehabilitation, and also in forensic voice comparison tasks. In this paper we present results for the acoustic analysis performed by two different voice analysis platforms and involving five sustained vowels uttered by 10 female speakers and 9 male speakers. We consider contemporaneous high-quality (HQ) and GSM voice recordings, as well as HQ and VOIP voice recordings. The analysis of the consistency of the acoustic analysis results by the two platforms provides useful insight regarding the intrinsic robustness of each acoustic parameter, the impact of the communication channel, and appropriate procedures seeking to extract full benefit of the available data in a forensic voice context.