Voice Identification – Ed Primeau

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This is an exacting science that has huge benefit to the courts.

When comparing spoken word samples for the purpose of identification, the scientific community, state police crime labs, forensic experts and designers and developers of electronic (especially computer) equipment and testing software programs, requires the examination of every aspect of the words spoken.  The words themselves, the way the words flow together, the pauses between the words, the way the words are formed by the mouth and larynx.  The forensic expert must careful examine all scientific evidence and follow procedures.

These scientific procedures include:

1. You must establish that the quality of the recording in question is acceptable and workable.  Sometimes, it may be necessary for the expert to apply some light equalization or other non destructive processing to reduce or remove background noise. At the same time, make sure the sample is long enough to conduct the testing.  In my opinion, this is a sample longer than thirty seconds.
2. Visual examination of the original recording.  This includes physical characteristics of the tape or digital recorder.  You must examine the cassette or other tape source to determine if there are visual signs of tampering or alteration.
3. Visual examination of the sound wave, sonogram and spectrograph.  Once the recording has been visually inspected and no signs of tampering can be found, the recording is loaded into a computer and tested using software tools to tell about the recordings characteristics.  This same process is applied to the exemplar to determine those characteristics using the same software.
4. Create an exemplar of the accused for comparison to the measurements taken from the evidence as outlined above.  The speech must be the same as the speech on the evidence in order for the testing to be accurate. However, it is still possible to compare speech if the exemplar is of another origin or conversation.
5. Audio examination of the speech pattern, pronunciation, voice tone and inflection, accent, dialect and specific characteristics (like a lisp or significant “s” delivery). There is a rhythm of how an individual speaks and regardless if trying to disguise speech for the exemplar, the rhythm still shows through.  The expert must pay careful attention to the rhythm of spoken word formations.  I listen to single words as well as phrases and sentences.  Most always, I load in to my computer original evidence sections of spoken word recordings and edit exemplars back to back with the original sections.  It is always helpful to then make a sub file of words within the section back to back with exemplars.  I like to cut and paste the original / exemplar back to back samples so as to repeat the assembly over and over helping the auditory identification process.  That way, your ear can experience the sounds, vowel formations and consonants without interruption.

There are a lot of character traits that can be experienced in a spoken word recording if you listen carefully.  I have been working with professional speakers and other spoken word recordings since 1980.  In those days, we would edit ¼” reel to reel tape with razor blades to make a recording sound like it was recorded start to finish without a single mistake. Some of my edits were pretty tricky.  I got so good I could split words in two and even three edits to fix a problem or shorten a script.  When you do this enough, you get to understand the characteristics of speech patterns.

Another part of my then job was to, on occasion, have to re record a portion of speech on a different day from the same voice that made the recording and make it sound as if the revision never happened.  I got quite good at this because it happened often and my job depended on it.

When conducting the examination, not only do I look for similarities I also look for differences to help arrive at a conclusion (beyond a reasonable degree of professional certainty). These characteristics are evident in a person’s voice even if they attempt to disguise their voice.

There can sometimes be differences in speech patterns that can help identify clues in your identification puzzle.  I look for several similarities as well as differences, nasal resonance differences, voice tone with regard to inflection both similarities and differences.

After the investigation and testing procedures are complete, I arrive at one of the following conclusions.  They are: positive identification, probable identification, positive elimination, possible elimination or inconclusive.  The key is to have a methodology and standard procedure developed that you strictly follow every time you do a identification and comparison so your mind can follow along and the results are accepted in the scientific community and courts.  This is my procedure that I follow when conducting voice identification.

For any questions or more information, call or email Ed@PrimeauProductions.com.