Namely, the individual actually effecting the tape falsification is attempting to obscure or disrupt important features of the originally recorded event or subject of interest. This is accomplished through various masking techniques. Secondly, falsification efforts are often designed to misdirect the attention of the listener to an irrelevant aspect or feature of the signal or an event of interest. A gap can contain buzzing, hum, or silence. Transients may indicate tape splicing or some other interruption of the recording process.
Fades can cause inaudibility and are considered gaps when the recording becomes fully inaudible.
Common equipment sounds include hum, static, whistles, and varying pitches. Critical Listening The forensic tape specialist will normally listen with high quality head phones and professional recording equipment to the original tapes prior to conducting any instrumental examination. He examines all recorded events to include both foreground and background sounds and listens for abnormal changes, absences, or presences of differing environmental sounds. He concentrates on voices, conversation and other audible sounds. Physical lnspection Magnetic Development Spectrum Analysis Employs the use of specialized computer equipment which measures the frequency spectrum of the recorded tape and provides a visual interpretation of the frequency vs. amplitude, frequency vs. amplitude vs. time displays.