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WELCOME offers expert  reports in forensic voice comparisons and a number of other forensic speech and audio services for government agencies, lawyers, and private clients. For voice comparisons we use proven auditory and instrumental phonetic analysis techniques based on specialist knowledge and years of casework experience.

With appropriate speech materials, speaker comparisons are made using up-to-date and validated voice biometric methods. For that purpose uses cutting-edge language, text, and channel-independent Phonexia speaker identification software.


Dr. Gfroerer has retired as head of the Forensic Speech, Language and Audio specialist division of the German Federal Crime Lab. He has studied psycholinguistics, phonetics and psychology at the Ludwig-Maximilians-University in Munich. After earning a doctorate in the field of cognitive psychology, he was a research assistant in different projects at the Ludwig-Maximilians-University and at the Max Planck Institute for Psycholinguistics in Nijmegen, The Netherlands. His work focused on operation and control of forensic voice comparisons for penal courts and prosecution and on research and development in the field of voice biometric analysis. From 1990 to 2018 he worked as an expert in Forensic Speech, Language and Audio for the German Federal Criminal Police (Bundeskriminalamt). From 2006 to 2010 he was chairman of the ENFSI (European Network of Forensic Science Institutes) Expert Working Group Forensic Speech and Audio Analysis. In his career he has collaborated in the development of standards for forensic speaker recognition and authored numerous court reports and scientific papers. After his retirement in the end of 2018 he became an expert and consultant in private practice.



Comparison of different voice and linguistic patterns ("voice prints") with regard to possible speaker identity or non-identity using classical forensic-phonetic and validated biometric procedures. The process is sometimes referred to as forensic voice analysis, speaker recognition or voice identification.


Writing down transcripts of difficult to understand or disputed utterances for investigative or evidential purposes.


Analyzing recordings of unknown speakers to reveal information about aspects of identity like regional accent, language background or any other which may be apparent from their speech.


Preparation of an expert opinion or report based on national and / or international recommendations.

Contact to learn more about our services and what we can do for you.

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