Smartphone-Based Open Research Platform for
Hearing Improvement Studies


  • This research is supported by National Institutes of Health (NIH)-National Institute on Deafness and Other communication Disorders (NIDCD) under award number R01DC015430.The content of this website is solely the responsibility of the contributors and does not necessarily represent the official views of the National Institutes of Health.

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Smartphone-Based Open Source Research Platform for Hearing Improvement Studies

 The smartphones used for our research platforms include iOS-based smartphones (Apple iPhones) and Android/-based smartphones ( Pixels, Galaxy, Nexus). We have also use several wire and wireless hearing aid devices (HADs) and associated electronic components from leading manufacturers such as Starkey, Oticon, Resound, and Phonak.

We develop new signal processing algorithms to suppress all types of background noise and enhance speech signals with high intelligibility and perceptual quality for improving hearing study and hearing aid applications. Powerful features of smartphones are used such as processor, single and multiple microphones, wire and wireless connectivity, touch screen and display panel.  All developed algorithms are tested objectively and subjectively in real-life environments and run on smartphones in real time using no additional or external hardware. In addition to the clinical testing of smartphone-based platform conducted using participants in audiology labs at the Callier Center of the University of Texas at Dallas (UTD), we provide all required tools to independent research and audiology labs, in many places off-campus, for testing our algorithms and the smartphone platform for hearing aid applications. The feedback from our clinical testing, participants, and independent labs and evaluators are instrumental to advancing and refining our signal processing algorithms and smartphone-based platform.     


The smartphone-based platform provides a cost-effective, stand-alone, portable, and easy-to-use system for researchers, audiologists, engineers, educators, and students to explore and develop new methods and conduct clinical testing for improving hearing study and advancing hearing aid applications. 

Research and Development Platform:

As shown in Figure 1, the smartphone-based open source research platform for hearing improvement studies that is being developed and tested consists of:

– iPhones with iOS operating system,

– Pixel, Galaxy, Nexus phones Android operating system.

Figure 1.   Smartphone-based Open Source Research and Development Platform


Architecture, Signal Processing Algorithms, and Operation of the Developed Smartphone-based Open Source Research Platform:


Programming Languages used:

Programming language used in our development were Matlab, C, Python for initial algorithm development and testing. These programming languages are widely used by programmers and researchers conducting hearing improvement study.

The codes written in Matlab are then converted to C and tested again. The C codes are then compiled on a PC/laptop running the software shell environments of smartphones to generate executable codes as apps. The executable codes are then downloaded from the PC/laptop into iOS/iPhone and Android/Pixel/Galaxy smartphones.

Apple CORE AUDIO and SUPERPOWERED shell software utilities are used for accessing and using the input/output (I/O) of iPhone7 & 10 and Pixel 1,2, and 3, as well as the Galaxy smartphones, respectively.

Apple iMAC and DELL computers and laptops are used to develop and test our software and algorithms /apps in engineering labs and the clinical /Audiology testing labs.


Here are the details for all research platform:


Delay measurements

Here are some round trip latency measurements for popular smartphones: 



Operating System

Sampling  Rate(kHz)/ Buffer length(samples)/ Latency(ms)

Google Pixel 3

Android 9 (PQ2A.190205.001 5163636)


Google Pixel 2

Android 8.1.0 (OPM4.171019.016.B1 4720843)


Google Pixel 2 XL

Android 8.1.0 (OPM4.171019.015.A1 4682895)


Google Pixel

Android 8.1.0 (OPR3.170623.013)


Google Pixel XL

Android 8.1.0 (OPM1.171019.016 4503492)


Samsung Galaxy S7 

Android 6.0.1 (MMB29K G935FXXU1APEK)


Huawei Nexus 6P

Android 6.0.1 (MMB29K 2419427)

48/ 192/ 18*

LGE Nexus 5X

Android 6.0.1 (MMB29P 2473553)

48/ 192/ 18-37*

Motorola Nexus 6

Android 6.0 (2172151)

48/ 192/ 33#

LGE Nexus 5

Android 6.0 (2172151)

48/ 192/ 38#

iPhone 6 


48/ 64/ 9*

iPhone 6 Plus


48/ 64/ 9*