PRAAT Stanford University

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Short Tutorial,Pascal van Lieshout Ph D, University of Toronto Graduate Department of Speech Language Pathology Faculty of. Medicine Oral Dynamics Lab ODL,A Introduction, This tutorial provides an introduction to some of the basic procedures in the program. PRAAT This is a freeware program for the analysis and reconstruction of acoustic. speech signals The software can be downloaded from the following website. http www fon hum uva nl praat This page also includes a PRAAT beginner s manual. written by Sidney Wood PRAAT can be used on different operating systems see. PRAAT website for more information but this tutorial is based on Windows 2000 OS. PRAAT is a very flexible tool to do speech analysis It offers a wide range of standard. and non standard procedures including spectrographic analysis articulatory synthesis. and neural networks This tutorial specifically targets clinicians in the field of. communication disorders who want to learn more about the use of PRAAT as part of an. acoustic evaluation of speech and voice samples The following topics will be covered. 1 Finding information in the Manual,2 Create a speech object. 3 Process a signal,4 Label a waveform, 5 General analysis waveform intensity sonogram pitch duration. 6 Spectrographic analysis,7 Intensity analysis,8 Pitch analysis.
9 Using Long Sound files, In this tutorial readers are assumed to be already somewhat familiar with standard. Windows 9x NT 2000 tools like opening and closing windows making windows smaller. or bigger etc If not please ask your colleagues who are more familiar with PC Windows. OS for help or check the following website http search support microsoft com for. more information on Microsoft products If the instruction mentions the word click. ing it simply means that you have to position your mouse cursor on top of the. indicated location and press the Left mouse button If another mouse button is required. this is explicitly mentioned in the text As usual in Windows once you made your choice. for a particular window you confirm by clicking the OK button If you want to go back. or cancel just click the Cancel button The main menu options are located on the right. PRAAT a system for doing phonetics was developed by Paul Boersma David Weenink at the. Phonetic Sciences department at the University of Amsterdam. hand side of the Praat Objects window but the contents of the menu may change. depending on the type of sound object you have selected. Please notice that earlier versions of PRAAT may differ in layout and function from the. version described here PRAAT v 4 1 Comments and suggestions on this tutorial are. welcome just send an e mail to p vanlieshout utoronto ca. PRAAT users can also join a discussion list which provides a useful forum for asking. questions as well as a database for sample scripts More information can be found here. http uk groups yahoo com group praat users, THIS DOCUMENT AND OTHER DOCUMENTS PROVIDED PURSUANT TO THIS TUTORIAL ARE FOR INFORMATIONAL. PURPOSES ONLY The information type should not be interpreted to be a commitment on the part of the author. and the author cannot guarantee the accuracy of any information presented after the date of publication. INFORMATION PROVIDED IN THIS DOCUMENT IS PROVIDED AS IS WITHOUT WARRANTY OF ANY KIND The. user assumes the entire risk as to the accuracy and the use of this document This document may be copied and. distributed subject to the following conditions, 1 All text must be copied without modification and all pages must be included. 2 All copies must contain a copyright notice and any other notices provided therein. 3 This document may not be distributed for profit,Toronto May 29 2003. B Working with PRAAT,1 Finding information in the Manual.
If you open the program2 the following two windows will appear. The window to the left is the Praat objects window On the left hand side you will. normally see a listing of your speech files objects in PRAAT language which can. either be created from scratch see section 2 1 15 or read from a file section 2 17. The window on the right is the Praat picture window and is used for plotting graphs. These can be saved in various formats including an EPS postscript3 or a Windows. Metafile for later word processing purposes or they can be printed directly using print. CTRL P in the file menu, Information about the program and all its procedures can be found in the PRAAT manual. by simply clicking on the Help button in the main menu of the PRAAT objects window. If you do that try it now you will find the following options available to you. If not already present create a shortcut to the praat exe file on your desktop for easy access. Postscript files can be read and printed using the program Ghostview gsview32 exe version 2 5 or. higher This is a free downloadable program see homepage http www cs wisc edu ghost. Most options speak for themselves and you can try them out for yourself The tutorials. are useful in that they provide more information about how to deal with specific topics in. PRAAT For those who want to use scripts in PRAAT to automate certain procedures the. Scripting tutorial is highly recommended More information about the use of formulas. operators functions etc can be found in the Formulas tutorial Check the Frequently. Asked Questions section with answers to common issues raised by users and make sure. you are aware of recent changes to the program listed in the What s new section The. option that will be used most often by the majority of users is the Search Praat manual. also notice that some functions have short cut keys in this case Ctrl M Click on the. option try it now and the following window will appear. Simply type a search string in the empty space of the window and you will find the. information that is available on your search topic For example find information on the. following topics,spectrogram, As you will notice some queries will give you a lot of options others are more. restricted, Remember that you can always invoke this Help function from anywhere in the program. and that most procedures allow you to invoke specific help information directly from. their window menus see for example the Search Manual window above. 2 Create a speech object, Before analyzing speech samples it is important to adjust your sound card options. properly To access these options you have to open the Volume control window For. Windows 2000 the following steps apply4, 1 Go to Start of the Windows Task bar left lower corner.
2 Go to programs accessories entertainment select volume control. 3 This will bring up the following or a similar window depending on the sound. card that is installed on your PC,4 Go to Options properties select recording. 5 Now you will see a number of options including Line In Microphone. 6 Select microphone by clicking on select button White Square below volume. meter and deselect all other options Adjust Volume meter if necessary to about. halfway the scale You can leave this window open and put it on the Task bar by. clicking minimize button right upper corner first button to the left This. will allow you to adjust settings later on, 7 From the main menu in the PRAAT objects window select NEW. 8 This will open the following window, For other versions of Windows please see appropriate help information. 9 In most cases you will record a single speech or voice sample and for that. purpose you can select Record mono Sound If you want to make stereo. recordings you obviously have to use Record stereo Sound The latter option. for example can be used to digitize the stereo output signal of the EG 2 PC. Electroglottograph from Glottal Enterprises, http www glottal com electroglottograph html thus giving you access to a. simultaneous recording of a speech and EGG signal, 10 Next the SoundRecorder window will appear shown here for mono recording.
11 First set the sampling rate In most cases the default 22 kHz will be more than. sufficient If your computer has less disk space you may want to use a lower. sampling rate 11 kHz If you want to record at CD quality select the highest. sampling rate 44 kHz This means you will have to store 44100 samples per. second per channel about 176400 Bytes with a 16 bit Sound card. 12 To record a signal use a preferably high quality microphone connected to the. MIC input do not use Line Input from the sound card and click the Record. button Some standard cheap computer microphones will not pick up. frequencies below 100 Hz check specifications, 13 Take a deep breath and speak the sentence we stop doing the right thing three. times Watch how the meter shows input level by green bars If you are finished. click the Stop button Now the signal is stored in RAM Random Access. Memory but not yet available for further processing except that you can listen. to the recording by clicking Play, 14 If the recording is to your satisfaction check with Play you can add a name for. the recording in the To list box in stereo recording mode you will see two of. these boxes one for the left and one for the right channel and click on the To. list button This will put your object in the Objects window. 15 If you now go to the Objects window you will find your sound object under the. name Sound name You can always change this into any other name if you. like Just click on Rename lower part of window and write down a new name. e g we stop It is a good strategy to give objects easy identifiable names. 16 This is just one example of creating a speech object You can also digitize a. speech sample from tape DAT or cassette using the line input from your sound. card But make sure you select Line In from the Volume Control window and. deselect the microphone input Also you may wish to set the Line In Balance. option select Playback mode under options properties to mute otherwise. you get a continuous auditory feedback while you are recording this however. may be useful to check the contents of a tape, 17 Finally you can read files from disk PRAAT supports various formats. including so called long sound files Basically these are pre recorded sound. files that are stored on disk and the program will allow you to select small. portions of the total signal for analysis This way you can have files of up to. several hours if your computer has enough disk space which can be handled in. a piece wise manner In this tutorial I will deal with the recording and handling. of long sound files later section 9,3 Processing a signal optional. 1 There are many things you can do with a speech object in terms of processing. You can filter the signal enhance specific frequency regions etc In this section. I will only describe the option of filtering the signal In general this is not. necessary in PRAAT but if you want to focus on a specific frequency region. the filter option comes in handy, 2 The first step is to select the original sound object click on its name in the list.
3 To filter the signal do the following, Select Filter right hand menu of Object window Filter formula. Change the formula to a low and high pass value in this case I create a high. pass filter at 10 Hz and a low pass filter at 5000 Hz. o if x 10 or x 5000 then 0 else self fi rectangular band filter. N B the x 10 is set to a arbitrary low value if your microphone does. not pick up frequencies below 100 Hz set this value to 100 and click. This will create a new filtered object in the list name filt. 1 Play both the original and processed signal try it now Can you hear a. difference,4 Label a waveform, 1 Sometimes it can be useful to segment a speech waveform and attach labels to. each segment, 2 Select the original non processed sound object by clicking on its name. 3 Go to label segment and select To Text grid This will bring up the. following window, 4 Change the names under the Tier names option to identify segmentation. categories e g words syllables sounds use space to separate names So the. labels you input here are meant to indicate a level of segmentation not the. individual items Make sure you erase the default names Mary John bell. because they make no sense to you later, 5 The Tier names are used to provide a label for intervals or specific discrete.
time points The labels that appear in the Point tiers box are automatically. assigned to points whereas the labels provided in the input window for the. Tier names are assigned to temporal intervals for e g the durations for the. words in a given utterance I will focus on intervals only in this tutorial so you. can leave the input window for Point tiers blank, 6 Select both the speech object and the Text grid they share the same name. using the CTRL key click on speech object depress CTRL key and then click. on Text grid, 7 On the right hand side of the window a new menu will appear Select Edit and. the following window will appear obviously the speech signals will look. different for your samples, 8 Maximize the window using the appropriate Windows button You can. listen to the entire speech sample by clicking on the lowest horizontal Play bar. see picture The upper Play bars are divided in columns as determined by the. cursor position and or selection see next subsection. 9 Now you can segment words and syllables in the following way. First select a portion of the total signal remember you recorded three. separate sentences originally e g the middle sentence You do this by. PRAAT Short Tutorial A basic introduction Pascal van Lieshout Ph D University of Toronto Graduate Department of Speech Language Pathology Faculty of Medicine Oral Dynamics Lab V 4 2 1 October 7 2003 PRAAT 4 1 x PRAAT VARIATIONS

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