Klatt Synthesizer

The Klatt Synthesizer is a speech synthesis software designed by Dennis Klatt in 1980. Since then, it has undergone modifications by Keith Johnson and is an excellent tool for any job which requires speech synthesis. The synthesizer is a hybrid of parallel formant synthesizers and cascade formant synthesizers, allowing the modeling of both vowels (using the cascade configuration) and fricatives and stop bursts (using the parallel configuration).

How to use

Parameters

The parameters for the synthesized recording fall under two categories: constant and varied. Constant parameters, such as duration (du) or number of cascade formants (nf), cannot change during playback. Varied parameters, such as f0, can be set to change at different time points during playback. See Klatt Synthesizer Parameters for a list and description of possible parameters.

Using a .klp file

One method of using the Klatt Synthesizer is to create a .klp file that contains all of the desired parameters. It is important to remember that in order to be properly read by the synthesizer, the parameters must be entered with care so that they will result in the intended output. A .klp file consists of three ordered sections, all of which are optional:

1. A block of comments at the top

2. A constant parameters section

3. A varied parameters section

Lines in the comment section begin with ‘#’. Constant parameters are provided one per line. They consist of the parameter name and its integer value, separated by whitespace. The varied parameters section is introduced by the line consisting of exactly:

_varied_params_

This line is followed by a whitespace delimited table of varied parameters, in which the columns are the parameters, and the rows are the time points. The first line of the table is a header defining the columns. Each column name defined in this header must be a valid parameter name, or the name must begin and end with ‘_’, in whichcase the column is ignored. An example of a .klp file complete with parameters can be found in /klsyn/doc/testklp.klp

Once you have saved your parameter file with the extension .klp, you can run the Klatt Synthesizer by typing

>klattsyn.py myparamfile.klp

into the terminal. A .wav file will then be created containing the synthesized speech according to the parameters.

Using the interactive interface

A somewhat simpler and less painstaking method of using the synthesizer is by using the interactive interface, which can be summoned by entering

>klattsyn_interactive.py

into the terminal, which brings up the interface. From here, you can follow the instructions to to design your synthesized speech, which will automatically create a .klp and .wav file.

Creating a continuum

A wide range of phonetics experiments require the creation of a continuum between two speech sounds. The Klatt Synthesizer allows one to create such a continuum. To do so, enter

>klp_continuum.py

into the terminal. This will prompt the synthesizer to ask for two klp files between which it can create a continuum. After entering the two .klp files, the synthesizer will automatically create a continuum between the two sounds.