Just a quick thought about whether or not the experts are to be subjected to a Frye hearing. As with most any issue in the law, a fundamental pivot point is defining the question or framing the issue. If the question is "is spectrographic analysis accepted in the scientific community?" the answer is "Yes." But, if the question is "is there a scientifically accepted method to perform voice ID from a sample of a person under stress, with the sample voice being outdoors in a reverberating environment, communicated through (50) feet of air, to a phone, and recorded on 8 kHz 911 digital equipment (and the sample is contaminated with other, overlapping sounds)?" The answer is no - see battling experts. If there was a scientifically accepted method for this, the experts would agree on the ultimate answer.