|The FFMTIMIT corpus contains the previously unreleased secondary microphone waveforms for the TIMIT Acoustic-Phonetic Continuous Speech corpus. The primary microphone waveforms, which were recorded using a close-talking noise-cancelling head-mounted Sennheiser microphone (model HMD-414), are available from the LDC on NIST Speech Disc 1-1.1 (LDC93S1). The secondary microphone used in the recording of the TIMIT corpus was a Breul & Kjaer 1/2" free-field microphone (model 4165). |
While the Sennheiser microphone recordings are relatively "clean" with respect to non-speech noise, the FFMTIMIT recordings includes significant low frequency noise, which was due to the HVAC system and mechanical vibration transmitted through the floor of the double-walled sound booth used in recording. Because it is noiser than its TIMIT counterpart, the data of FFMTIMIT may be used in the development of more noise-robust speech recognition systems. In addition, this data may be of value to researchers involved in vocal tract modeling because the B&K microphone has extremely flat free-field frequency response and calibration tones are provided.
Note that the B&K TIMIT data contained with this release has not been processed through any highpass filter, (e.g., the 1,581-point filter described in the paper "The DARPA Speech Recognition Research Database" by Fisher, Doddington and Goudie-Marshall in "DARPA TIMIT Acoustic-Phonetic Continuous Speech Corpus CD-ROM," NISTIR 4930 / NTIS Order No. PB93- 173938.)