STRAIGHT, a speech analysis, modification and synthesis system
last update: Wed Jan 4 11:30:12 JST 2017

SFT spectrogram

(Current STRAIGHT versions are compatible with MATLAB R2016b. They, excluding GUIs, are also compatible with GNU Octave. 04/Jan./2017)


STRAIGHT is a tool for manipulating voice quality, timbre, pitch, speed and other attributes flexibly. It is an always evolving system for attaining better sound quality, that is close to the original natural speech, by introducing advanced signal processing algorithms and findings in computational aspects of auditory processing.

STRAIGHT decomposes sounds into source information and resonator (filter) information. This conceptually simple decomposition makes it easy to conduct experiments on speech perception using STRAIGHT, the initial design objective of this tool, and to interpret experimental results in terms of huge body of classical studies.

The most up to date STRAIGHT is called TANDEM-STRAIGHT (2008 ICASSP) that is a complete reformulation based on a new representation of power spectra of periodic signals. The original idea which lead to STRAIGHT was emerged at ATR Human Information Processing Research Laboratory in 1996. The first stage of development was supported by Japan Science and Technology agency (JST), under its CREST research promotion program. This "Auditory Brain Project" established the foundation of STRAIGHT and initiated subsequent research and development of various applications based on STRAIGHT.

Availability of STRAIGHT

There are two contact points to get access to STRAIGHT codes. For academic use, please contact to the author of the system. For non-academic use, please contact to the technical liaison office. Please put a word "STRAIGHT" in the Subject field of your mail.

Upcoming events

Past events

What STRAIGHT can do (our work)

What STRAIGHT can do (contributions of users and collaborators)

A list of citations on STRAIGHT provides a overview of the range of applications. The followings show selected topics.

Selected articles on STRAIGHT

Selected articles and presentations

Please mail to (