HTIMIT and LLHDB: speech corpora for the study of handset transducer effects

This paper describes two corpora collected at Lincoln Laboratory for the study of handset transducer effects on the speech signal: the handset TIMIT (HTIMIT) corpus and the Lincoln Laboratory Handset Database (LLHDB). The goal of these corpora are to minimize all confounding factors and produce speech predominately differing only in handset transducer effects. The speech is recorded directly from a telephone unit in a sound-booth using prompted text and extemporaneous photograph descriptions. The two corpora allow comparison of speech collected from a person speaking into a handset (LLHDB) versus speech played through a loudspeaker into a handset (HTIMIT). A comparison of analysis and results between the two corpora addresses the realism of artificially creating handset degraded speech by playing recorded speech through the handsets. The corpora are designed primarily for speaker recognition experimentation (in terms of amount of speech and level of transcription), but since both speaker and speech recognition systems operate on the same acoustic features affected by the handset, the knowledge gleaned is directly transferable to speech recognizers. Initial speaker identification performance on these corpora are presented. In addition, the application of HTIMIT in developing a handset detector that was successfully used on a Switchboard speaker verification task is described