used in pre-operation to record the voices of chosen patients to be compared with the post-operation usage, along with more complex recordings using an electroglottograpy, photoglottography, and videokymography. Medical professionals have the ability to read and understand the results from the complex recordings, but knowledge from a voice professional is needed within these experiments for accurate results. Voice experts were an important to tie the physical examination of the vocal cords to the neurological examination to ensure the success of the surgery because of their trained ear. Perceptual evaluation of voice is heavily reliant on voice quality, a factor assessed preferably by voice specialists (speech therapists). A professional voice analyzer has a trained ear and can block out excess variants that can be deceptive from the results. Use in forensics Voice analysis is used in a branch of forensic science called audio forensics. These analyses are generally performed on evidence for the purposes of evaluating the authenticity of the audio in question, enhancing features of the audio that may be hidden beneath distracting background noise, interpreting the audio from the perspective of a forensic expert, or in some cases for the purposes of speaker identification. An expert will employ a variety of techniques in their analysis. The minimum of procedures are "critical listening, waveform analysis, and spectral analysis". Critical listening involves a thorough breakdown of both foreground and background sounds through repetitive listening. Waveform analysis visualizes the audio for the examiner to see any irregularities that may occur. Spectral analysis visualizes the frequency of the audio for an examiner to pick out features of interest. One case in which audio played a larger role is the Trayvon Martin case, where a recording of a call made to the police was analyzed to determine if background screams came from George Zimmerman or from Martin. Forensic Voice Experts in forensic voice analyze recordings by examining transmitted and stored speech, enhancing it and decoding it for criminal investigations, court trials, and federal agencies. To utilize audio recordings in court, a forensic phonetician must authenticate the recording to detect tampering, enhance the audio, and interpret the speech. Their first job is to ensure that the speech in the recording being used is comprehensible. Oftentimes, samples have poor sound quality due to environmental factors such as wind or movement. Other times the sound degradation is due to technological issues within the recording device. Any investigative