Comparability of Modern Recording Devices for Speech Analysis: Smartphone, Landline, Laptop, and Hard Disc Recorder

Abstract

Background: Large-scale multi-site experimental and clinical speech protocols require high-fidelity, easy-to-use speech recording technologies. However, little is known about the reliability and comparability of affordable, portable and commonly used technologies with traditional well-validated devices (e.g., a hard disc recorder with a high-quality microphone). Objective: To examine the comparability of speech and voice samples acquired from protocols involving high- and low-quality devices. Methods: Speech samples were acquired simultaneously from 15 healthy adults using four devices and analyzed acoustically for measures of timing and voice quality. For the purpose of making initial comparisons, methods were deemed comparable if the resultant acoustic data yielded root mean squared error values ≤10% and statistically significant Spearman's correlation coefficients. Results: The data suggest that there is significant and widespread variability in the quality and reliability between different acquisition methods for voice and speech recording. Not one method provided statistically similar data to the protocol using the benchmark device (i.e., a high-quality recorder coupled with a condenser microphone). Acoustic analysis cannot be assumed to be comparable if different recording methods are used to record speech. Conclusions: Findings have implications for researchers and clinicians hoping to make comparisons between labs or, where lower-quality devices are suggested, to offer equal fidelity.

Evaluation of Speech-Based Digital Biomarkers: Review and Recommendations

“…In addition, the design of the user interface could also affect the quality of recordings, e.g., by including empty periods in the recordings to estimate ambient noise, or by providing feedback to the participant in the form of beeps, text, or voice prompts to improve task compliance. Several recent papers have examined the comparability of audio recordings made across different devices, including smartphones [19][20][21][22][23]. While several studies found that smartphones yield recordings of acceptable quality compared to standard microphones [20,22,24], others reported mixed findings with the differences relating to the particular audio outcome measures used [19,21,23].…”

“…Several recent papers have examined the comparability of audio recordings made across different devices, including smartphones [19][20][21][22][23]. While several studies found that smartphones yield recordings of acceptable quality compared to standard microphones [20,22,24], others reported mixed findings with the differences relating to the particular audio outcome measures used [19,21,23]. A few studies have examined the effects of ambient noise on voice recordings, with one recommending a threshold of 50 dBA as an acceptable level for their particular speech tasks and outcome measures [21,25].…”

Static measurements of vowel formant frequencies and bandwidths: A review

“…Obtaining a high fidelity recording of the speech signal and appropriate application of spectral analysis are essential to the acoustic analysis of speech. Information on microphone and recorder specifications needed for speech recordings is available in several papers (Hunter, Spielman, Starr, and Popolo, 2007; Plichta, n.d.; Sustainable Heritage Network, 2006; Švec & Granqvist, 2010; Vogel, Rosen, Morgan, & Reilly, 2015). For spectral analysis of formant pattern, the commonly used methods are the Fast Fourier Transform (FFT) and Linear Predictive Coding (LPC).…”

Reliability of Clinical Voice Parameters Captured with Smartphones — Measurements of Added Noise and Spectral Tilt

“…Smartphones are increasingly used to collect speech data for acoustic analysis, and several authors have suggested that smartphones have sufficient reliability for voice analysis with a clinical purpose [1]- [6]. [7] took a less optimistic stance on this and argued that previous analyses partly rested on false assumptions about the nature of the problem.…”