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A Speech Quality and Intelligibility Assessment Project Using Google Voice

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2014 ASEE Annual Conference & Exposition


Indianapolis, Indiana

Publication Date

June 15, 2014

Start Date

June 15, 2014

End Date

June 18, 2014



Conference Session

Projects in ECE

Tagged Division

Electrical and Computer

Page Count


Page Numbers

24.104.1 - 24.104.11

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Paper Authors


Ying Yu University of Hartford

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Dr. Ying Yu received her B.Eng. from Fudan University, Shanghai, China, in 2000. She received her M.Eng. and Ph.D. in Electrical Engineering from Brown University, R.I., USA, in 2003 and 2007, respectively. Since 2008, she has been teaching at the University of Hartford. Her current research interests are audio and speech signal processing, acoustic scene classification, speaker identification and verification, and teaching with new educational methods, including peer instruction, video games, and state-of-the-art CAD tools.

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A Speech Quality and Intelligibility Assessment Project Using Google VoiceAbstractIn this paper, a speech quality and intelligibility assessment project using Google Voice isintroduced. Speech quality and intelligibility assessment is an essential topic in any audio andspeech signal processing course, which is widely offered as a senior elective or graduate levelcourse in the electrical engineering curriculum. Speech quality and intelligibility assessment hasbecome an extremely important topic due to the increasing demand in areas such as digitalprotocol analysis, Dolby-dts compliance analysis, audio device testing, etc.Traditionally, one of the biggest challenges in studying speech quality and intelligibilityassessment is the availability of real-life data. The voicemail feature of the Google Voice serviceallows users to download their own voicemails which are real Voice-over-Internet-Protocol(VoIP) speech. The voicemails are sampled at 11025Hz and compressed as MPEG audio layerIII (mp3). Google Voice also offers automatic transcription of the voicemails, which offers greatmaterial for students to examine the effects of vocabulary and contextual information on theintelligibility of speech.The speech quality and intelligibility assessment project introduced here includes three stages. Instage 1, students create a speech data bank using their own voice. Each student creates two setsof recordings. For the first set of recordings, they read the famous “rainbow passage” usingcontinuous speech. For the second set of recordings, they read a randomly selected group ofwords in the classic Modified Rhyme Test (MRT) using discrete speech. For each reading, theysimultaneously record their speech using a close talking microphone on their own PC, and at thesame time through a cellphone and record their speech using Google Voice’s voicemail system.After uploading their own recordings onto a commonly shared webpage (e.g. Blackboard’s ‘fileexchange’ page), students have access to each other’s recordings, which comprise a completespeech database including both the VoIP degraded speech and the clean reference speech. Instage 2, students subjectively assess the speech quality and speech intelligibility of eachrecording using the Mean Opinion Score (MOS) system. In stage 3, students create their ownMatlab programs to assess the speech quality and speech intelligibility of the recordingsobjectively. The algorithm used is similar to the Perceptual Evaluation of Speech Quality(PESQ) standard which is a legacy industry standard for objective voice quality testing.Students’ feedback in terms of their experience using Google Voice and their learningexperience are presented. The instructor’s own observations and conclusions, and future plan arepresented at the end.

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