FFMTIMIT

FFMTIMIT contains the previously unreleased secondary microphone waveforms for TIMIT Acoustic-Phonetic Continuous Speech. The primary microphone waveforms, which were recorded using a close-talking noise-cancelling head-mounted Sennheiser microphone (model HMD-414), are available from LDC on NIST Speech Disc 1-1.1 (LDC93S1). The secondary microphone used in the recording of the TIMIT corpus was a Breul & Kjaer (B&K) 1/2" free-field microphone (model 4165). While the Sennheiser microphone recordings are relatively "clean" with respect to non-speech noise, the FFMTIMIT recordings include 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.)

FFMTIMIT 数据集包含此前未公开的 TIMIT 声学-语音连续语音语料库的副麦克风波形数据。该数据集的主麦克风波形数据采用森海塞尔（Sennheiser）HMD-414型头戴式近讲降噪麦克风录制，可从美国语言数据联盟（Linguistic Data Consortium, LDC）获取，对应资源为NIST语音光盘1-1.1（编号LDC93S1）。本TIMIT语料库录制时使用的副麦克风为布鲁埃尔&基耶尔（Breul & Kjaer，简称B&K）4165型1/2英寸自由场麦克风。尽管森海塞尔麦克风录制的音频在非语音噪声层面相对“干净”，但FFMTIMIT数据集的录音包含显著的低频噪声，该噪声源于录制时使用的双层隔声播音室地板传递的暖通空调（HVAC）系统噪声与机械振动。由于该数据集相比原版TIMIT语料库的对应数据噪声更强，FFMTIMIT数据可用于开发抗噪性能更优的语音识别系统。此外，由于B&K麦克风拥有极为平坦的自由场频率响应，且数据附带校准音，该数据集对从事声道建模研究的科研人员具有较高的应用价值。需要注意的是，本版本发布的B&K版TIMIT数据未经过任何高通滤波器处理，例如费舍尔、多丁顿与古迪-马歇尔在《DARPA语音识别研究数据库》一文中提及的1581点滤波器，该文收录于《DARPA TIMIT声学-语音连续语音语料库光盘》（NISTIR 4930 / NTIS订购号：PB93-173938）中。