Audio Forensic Services

• Authentication of recordings: Authenticity examinations of audio and video recordings are normally conducted on the alleged original media, and can usually determine whether the information is original, continuous, and unaltered. The analysis consists of, as appropriate, listening, physical, visual, magnetic, instrumental, and computer evaluations, which can identify alterations and duplication processes.
• Identification and Classification of Non-Voice Signals: Examinations of non-voice signals, conducted with original media, include electronic signal analyses of recorded gunshot sounds, telephone signaling, mechanical sounds associated with weapons firing, room acoustics, and various background noises.
• Voice intelligibility enhancement: Enhancement examinations of audio information are normally conducted on the original media, and can often attenuate reverberation, tonal sounds, noise outside the frequency range of the voice material, and certain types of environmental and system noise; level the amplitude differences between louder and quieter voices; and correct speed errors. This analysis uses specialized forensic digital filters, gain-reduction devices, dedicated software, and unique playback systems, as appropriate.
• Spectral/aural comparison between voice samples:
  [Commonly referred to as "voiceprints" or "voiceprint comparison"]
  Voice comparisons between unknown recorded voice samples and known exemplars are normally conducted on the original media, and require at least ten (10) usable words spoken by the unknown talker and verbatim known voice exemplars, recorded through the same type of transmission line, i.e. telephone system. This technique uses critical listening and visual comparisons between sound spectrograms to provide a meaningful, but not conclusive, comparison.
• Duplication of Unique and Specialized Audio and Video Formats: These duplication processes allow for the copying of many unique and specialized media to standard formats readily usable by the client. Submitted media often include miniature, professional, unique on-the-body systems, antiquated, and proprietary digital formats.
• Preparation of video/audio sequences for court or other display purposes: These procedures produce professional-quality video and/or audio clips of interest in a designated display sequence. Effects can include transitions, looping, slow motion, zoom, magnification, and titling.
• Redaction of designated information from recordings: This examination allows for specific talkers or certain phraseology to be removed or isolated. This procedure is often requested based on a legal decision that certain recorded statements cannot be played to the jury, or when only certain designated voices in a conversation are pertinent.
• Repair of broken or damaged media: Broken or damaged tapes, housings, and other components can often be repaired, which will allow proper playback and duplication.
• Preparation of transcriptions: Transcriptions are normally prepared using the original media, and state-of-the-art playback and enhancement equipment, and by careful, repeated review of the recorded speech information using professional-quality headphones.
• On-Site Evaluations: On-site evaluations of acoustical sounds and environments require BEK TEK LLC personnel to travel to the designated locations, perform appropriate acoustical testing, analyze the collected information in the laboratory, and then draw conclusions regarding the collected material. Examples of these analyses include on-site testing of the audibility of speech in different locations in a building, and evaluations of equipment that cannot be removed from its present location.
• Expert Testimony Support: Provide expert testimony regarding laboratory examinations and on-site evaluations conducted by BEK TEK LLC personnel, and assist attorneys in cross-examination of opposing experts regarding their prior testimony, the scientific validity of their findings, their background and experience, and the methodology of their laboratory work.
• Technical Support and Training: Instruct attorneys, investigators, laboratories, examiners, and others regarding the scientific basis and methodology of forensic examinations of audio and video recordings; this can either be an individual consultation, or in a formal classroom environment. BEK TEK LLC personnel can also technically evaluate appropriate recording and analysis equipment.
• Research: BEK TEK LLC personnel can either provide technical assistance or conduct appropriate research in support of forensic areas, such as voice identification, digital authenticity, enhancement, and signal analysis.