Voice Identification Standards: Practical and Official

As an audio forensic expert who conducts voice identification, I receive calls from people around the world asking about voice identification. The American Board of Recorded Evidence provides voice identification standards that help me determine if I can identify a piece of audio evidence.

Some of the requests I receive are a stretch because the audio in question does not have enough words spoken in order for me to create an exemplar.  An exemplar is one of the most important tools to a voice identification test.  The exemplar must be made as closely to the original recording as possible.  The audio forensic expert often does not have as much control over the technology when making the exemplar as they would like.  In that case careful attention must be paid to the variable electronic readings in spectrograph measurement allowing or compensating for the variable.

In other words, if a piece of audio evidence was a telephone intercept or voice mail recording, the exemplar must be made using a telephone and recording device as similar as possible to the device that was used to create the original recording in question. This is where the attorney representing our side in the litigation comes in.  The attorney must petition the court during discovery to help the audio expert learn what equipment was used to record the original evidence.

This process was especially important back in the analogue days. Today’s digital recordings create much higher quality recordings and have different authentication processes.
Here are the American Board of Recorded Evidence voice identification requirements as accepted in the scientific community:


Standards for Comparisons Determination


The following are the standards accepted nationally by all professional organizations involved with voice identification, including the FBI, the Audio Engineering Society, the International Association for Identification, and the American Board of Recorded Evidence:

• IDENTIFICATION: At least 90% of all comparable words must be very similar aurally and spectrally, producing not less than twenty (20) matching words. The voice samples must not be more than six (6) years apart.
• PROBABLE IDENTIFICATION: At least 80% of the comparable words must be very similar aurally and spectrally, producing not less than fifteen (15) matching words.
• POSSIBLE IDENTIFICATION: At least 80% of comparable words must be very similar aurally and spectrally, producing not less than ten (10) matching words.
• INCONCLUSIVE: Falls below either the Possible Identification or Possible Elimination confidence levels and/or the examiner does not believe a meaningful decision is obtainable due to various limiting factors.
• POSSIBLE ELIMINATION: At least 80% of comparable words must be very dissimilar aurally and spectrally, producing not less than ten (10) words that do not match.
• PROBABLE ELIMINATION: At least 80% of the comparable words must be dissimilar aurally and spectrally, producing not less than fifteen (15) words that do not match.
• ELIMINATION: At least 90% of the comparable words must be very dissimilar aurally and spectrally, producing not less than twenty (20) words that do not match.

To learn more about voice identification, call 800.647.4281

Is It Still Elvis Presley̶? Cast Your Vote

Last Monday I did another radio interview for Elvis Express Radio. Joe from the network called me about 10 am EST and asked how I knew this song had Elvis Presley singing. I explained to him that I did forensic voice identification and compared the vocal to similar types of Elvis songs from around the same time. ‘What Now My Love’ was one of the songs I used as an exemplar, which is the second step when I conduct voice identification. In this case an exact exemplar could not be created for obvious reasons so we went with songs that were recorded around the same time and had similar vocal innovation.

We would like to know what you think about the new song. Do you believe it's Elvis Presley?



Joe from Elvis Express radio told me during my interview that he had been an Elvis fan for 40 years and he believed that “Living to Love You” was not sung by Elvis Presley. I told him that I respected his opinion and we concluded the interview.

I did not think much of it because I have been an audio engineer working with world renowned and local musicians and artists as well as a forensic expert for 27+ years. Of course I could be wrong; there is always a margin of error in any voice identification.

Today I received an email from the lawyer handling the sale of the song. Her update is very interesting. She hired author Tom Grace who is an Elvis expert to listen to the song and review the documents.
Tom has positive feedback regarding my forensic analysis. After he listened to the tape he confirmed that it had to be Elvis for a different reason than my forensic voice analysis determined.

"No one would try to make a tape to sound like Elvis with such a poor arrangement" was his first comment. The instruments were all out of balance including the piano. Tom said he could hear the piano and he believes he knows who the piano player was and who was playing the guitar and base.

He has researched the date and time that everyone was together and came up with February 24, 1965 in Nashville when they were recording the soundtrack for the Elvis movie “Harum Scarum.” There are three recordings documented from 11:00 p.m. to Feb 25 at 1:00 a.m.

He does not know what was recorded other than they worked on one record which was for “Harum Scarum.” The recording was not put on a reel and must have been direct to acetate because there is a popping sound in it. It was not copy written until 1976; a letter to Albert Lee states copy writing does not normally occur until the song is published.

Speculation is that Jimmie Crain heard that Elvis wasn't doing well in 1976, so he checked and found the song had not been previously copy written by RCA . He apparently decided to copy write it before something happened to Elvis.

Tom Grace will be publishing his findings and the lawyer representing the sale of the song, Violet Hinton, has contacted WWMT TV 3 to interview Tom Grace in a follow up story.

If you believe this song is Elvis Presley, hit the like button on the article link on Audio Forensic Expert's Facebook page. You can also email us at Primeau@PrimeauProductions.com.

Clarification for Authentication of Audio Recordings

The following article was written to help the legal community better understand the audio clarification process. The descriptions it includes will also help a lay person better understand the value of audio clarification.

All digital and analogue recordings have a noise floor. The term “noise floor” originated when manufacturers of analogue audio recorders referred to the extraneous noise that their machines created in addition to the desired recorded audio signals.

Often, a background noise constitutes most of the audio recording and covers a portion of speech that needs to be audible in order to determine a series of events pertinent to the case. Noises like the humming of a fan, air conditioning, heating systems, wind, and other unwanted sounds contribute to the audio recording noise floor. These noises can often be removed by the audio forensic expert (who is also known as the examiner) to help determine facts about the series of recorded events.

The extraneous sounds of background noise and noise floor can consist of a heating or air conditioning fan running, refrigerator motor, window fan, clock, fluorescent lighting, wind, rain, the running engine of a car, and even radio or television. All these sounds contribute to the background noise and noise floor of a recording and aid the forensic examiner in authenticating a recording. However, although these sounds can authenticate the environment of an alleged crime, this background noise can interfere with the forensic examination. It is appropriate and part of the forensic examiners job to remove these background sounds in order to authenticate or clarify an exhibit of audio recorded evidence.

Some of the recordings experts are asked to authenticate are confession recordings created by law enforcement agencies. Defendants exclaim, “That is not what I said, they edited it” or “There is more I said that has been edited out of the recording”. Due process entitles both parties in litigation to examine any evidence presented in their case. However, original recordings are not always available for examination. How do you as a law enforcement official feel about the absence of original recordings?

I have worked on cases where missing “original evidence” was considered spoliation of evidence. Personally, I believe that the circumstances of each case should be considered by the forensic examiner before any decision has been made by either party.

If there are noticeable questionable characteristics that the forensic examiner observes regarding the audio evidence, then the expert must notify the officials in charge of the findings during the preliminary examination phase of the forensic investigation. Original recordings are required for litigation cases. If they are not produced, a motion to suppress the evidence should be filed.