What is Digital Voice Stress Analyzer (DVSA)?

Voice Stress Analysis (VSA) is a procedure used for credibility assessment, truth verification or to determine psychological stress profiles. The technology has been used for over 50 years. BAKER-DVSA software has dramatically improved on that outdated technology. Over 25,000 various VSA systems are in use worldwide. More than 3500 U.S. law enforcement agencies use VSA. The U.S. Department of Defense uses VSA in its fight against worldwide terrorism.

Unlike polygraph the DVSA does not report “inconclusive” results.  Polygraph examiners report up to 60% “inconclusive” examinations.

In the fall of 2000, Air Force Research Laboratories (AFRL), Rome, NY and the National Institute Of Justice’s National Law Enforcement and Corrections Technology Center released its findings on voice stress analysis (VSA) technology. Those results confirm the accuracy and validity of VSA technology at 100%. An edited copy of the AFRL news release follows:

Rome, N.Y., ( AFPN) —

A three-year study by Air Force Research Laboratory Information Directorate engineers here has concluded several features of voice stress analysis are effective for detecting when a person is answering questions under stress. “The Department of Defense Polygraph Institute (DoDPI) provided us with tapes of investigations from two murder cases where the suspects eventually confessed and were found guilty,” “Using voice stress analyzers … (the) machines were accurate on 45 out of 45 instances.” Ed. Note: That is 100% accuracy.

Dr. Baker provided VSA training to the Rome Lab analysts and engineers for the above study, provided polygraph and DVSA training, and participated in Phase II with the DVSA. BAKER unique and proprietary stress pattern quantification and chart analysis techniques were utilized in the AFRL study – thus validating those techniques.

Earlier studies conducted by both government and private organizations show similar VSA validity and reliability.

Since its inception in the early 1970’s, Voice Stress Analysis credibility assessment technique is now utilized throughout the world by law enforcement investigators, arson investigators, military intelligence & counterintelligence units, psychologists, psychiatrists, insurers, and government agencies. VSA technology is effectively utilized worldwide in locations such as the European Communities, South Africa, Central and South America, Middle East, Asia, Israel, Egypt, Saudi Arabia, South Korea, the Balkans. Now, through DVSA software, the science is easier to use and more effective than ever before – at an affordable price. Private Law Enforcement Grants are available from our developer.

How does it work?

THERE ARE NO ATTACHED SENSORS, BLOOD PRESSURE CUFFS, and OR ELECTRODES as in polygraph examinations. Verbal responses are processed through a computer utilizing proprietary BAKER – DVSA software. The software detects, measures, and displays certain stress-related components of the voice. Superimposed on the audible voice frequencies are inaudible frequency modulations (FM) whose strength and pattern relate inversely to the degree of psychological stress in the speaker at the moment of utterance.

These involuntary frequency modulations result from minute oscillations of the muscles of the voice mechanism. Such oscillations, known as physiological tremor or micro-tremor, can be shown in the laboratory as a normal accompaniment to the activity of any voluntary muscle, occurring at a rate of 8-14 cycles per second. Most of the functional indicators of stress are attributed to the Autonomic Nervous System (ANS), physiological tremor as seen in the voice mechanism is controlled by the Central Nervous System (CNS); as the sympathetic branch of the ANS gains dominance in a stress situation, the micro-tremors are suppressed, and the FM in the voice utterance is moderated or completely disappears.

The voice is just the carrier of certain physiological reactions to psychological stimuli. The voice itself is not evaluated and any attempt to control the voice is a waste of energy. It simply does not work. There are no known countermeasures. Nervousness, medical disability or drugs have no effect on the evaluation.

Voice Stress Analysis examinations can protect one from improper criticism or accusations. It can verify veracity and honesty. It can verify the veracity of the account of the topics being discussed either from face-to-face interview, public speech from radio or TV, or from previous audio recordings. Cold cases are easily resurrected.

Our FORENSIC SYSTEM utilizing the BAKER-DIGITAL VOICE STRESS ANALYZER copyrighted¹ software is a fast and accurate diagnostic Voice Stress Analysis forensic truth verification system based upon sound scientific approaches, retaining some Psychological Stress Evaluator (PSE) validated and patented features. State-of-the-art high sample-rate digital capture of each utterance, space-age technology, Time-Domain Decimation, zero-padding, envelope decay, Frequency Domain Filtration, and Fast Fourier Transform digital signal processing is completed within a fraction of a second. Solutions for voice formant frequency display and Baker proprietary analysis algorithms create easy to interpret charted responses for VOICE STRESS ANALYSIS credibility assessment. This state-of-the-art software is installed into agencies’ existing computers. No need to purchase new equipment thus saving precious resources. Save thousands of dollars by obtaining DVSA software.

Combining the “science” of voice stress analysis and the “art” of truth verification testing, BAKER- DVSA requires standardized chart analysis, time-proven procedures, and specialized examiner training to excel in credibility assessment or covert narrative analysis. Our “system” consists of three interdependent elements; proprietary DVSA diagnostic software, appropriate test protocols, and a highly trained examiner using standardized analysis methods.

DVSA is a fully digital alternative to outdated VSA systems and polygraph. DVSA utilizes revolutionary innovations that optimize truth verification, intelligence and counterintelligence solutions providing examiners new insights like never before. DVSA techniques provide additional possibilities for covertly addressing intelligence and counter-intelligence matters. The system can be utilized for credibility assessment in any language and any culture and may be used to verify audio recording authenticity and conduct voice comparisons.

  • BAKER GROUP INTERNATIONAL is the sole source for the Digital Voice Stress Analysis system for truth verification and credibility assessment examinations.
  • DVSA is the only VSA that provides VAST (Voice Analysis Scoring Tool and ±0 Scoring Method) which confirms examiners’ conclusions.
  • DVSA is the only VSA which provides optional Voice Imaging Spectrograph for speaker identification and comparison.
  • DVSA is the only VSA which provides AutoReport which compiles and writes the report in the background as the examination is conducted saving valuable time. This is not a new feature. It’s been incorporated in our software since 2002.
  • DVSA is the only VSA with the copyrighted 17 stress pattern quantification method. It sets the standard in stress chart interpretation. Our chart interpretation method was utilized in the successful and important USAF Research Laboratory Study which validated VSA as 100% accurate. It does not include the “delayed stress reaction” theory which invalidates VSA approaches. We do acknowledge voice stress “carryover” but it must be less psychological stress present than the preceding utterance derived stress pattern. 
  • DVSA is the only VSA with 14 different test protocols shown on-screen from the software drop-down menu or on thumb-drive. Examiners need only to add issue specific information prior to testing.
  • DVSA is the only VSA featuring Streaming Voice Imaging displaying voice intensity instantly as the subject speaks saving valuable time.
  • DVSA is the only VSA capable of displaying answer Time Antagonistic Response Aletheometer (TARA) patterns.
  • DVSA is the only VSA featuring charts displaying derived stress patterns, time-domain, questions / answers, location on recorded  audio AM window, baseline, protocol, filter rate / mode and examination data.  Competitors utilize 4096 cycles per second of voice capture. Baker uses up to 44K cps
  • DVSA is the only VSA which digitally records the entire examination, questions & answers, to computer hard-drive permitting close observation of the subject. No keystrokes required to capture each answer as in competitors’ systems.
  • DVSA is the only VSA which operates with Microsoft Windows Windows 7 though Windows 11. Earlier versions, which are still available, continue to work with MS XP. Additionally, the software will install in desktops, laptops, netbooks and handheld computers using MS O/S.
  • DVSA software is password protected which permits installation on multi-user laptops while protecting the forensic credibility assessment applications program from unauthorized access.
  • DVSA software is protected preventing software pirating, overwriting or changing of the applications program.
  • Unlike our competitors, our developer is our primary Board Certified Instructor, practicing VSA examiner for 48 years, practicing polygraph examiner for 32 years, and a certified instructor and examiner for Post Conviction Sex Offender Testing (PCSOT), conducting over 10,000 examinations.
  • Unlike our competitors, our developer is a Court Qualified Expert in the field of forensic truth verification and legal investigations. He is a Fellow and Life Member of the professional organizations; International Society of Stress Analysts and the American Polygraph and Voice Stress Association.

We are leaders and innovators in VSA and voice biometrics technology development. DVSA is far superior to competitors’ “truth verification” systems.

Sample DVSA Chart / Report

Sample DVSA Page 1