A voice or sound recognition system including a microphone for converting a voice into an electrical voice signal, a frequency analyzer for generating a voice pattern in the form of a time-frequency distribution, and a matching unit for matching the voice pattern with registered voice patterns. A voice pattern sometimes contains a bass bar section starting from the beginning of the voice pattern over a time period. In one form of the present invention, the bass bar section is detected and/or eliminated before processing the voice pattern for the purpose of registration or matching. The voice level is sometimes too strong or too weak for appropriate processing. In another form of the present invention, a voice recognition system including a voice input cancelling function is provided. In addition, a system for detecting a voice interval for use in voice data processing, including a device for determining a start point of the voice interval is provided.