The Effect of Microphone Frequency Response on Spectral and Cepstral Measures of Voice: An Examination of Low-Cost Electret Headset Microphones

Awan, Shaheen N.; Shaikh, Mohsin Ahmed; Desjardins, Maude; Feinstein, Hagar; Abbott, Katherine Verdolini

doi:10.1044/2021_ajslp-21-00156

Cited by 8 publications

(5 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We extracted intensity-related, frequency-related, and periodicity metrics from simultaneous recordings and calculated differences, agreement intervals, and correlation coefficients between microphones. Based on previous findings, we hypothesize that agreement intervals between microphone set ups would be smaller than the expected clinical effect (thus acceptable) for f0 and for intensity-related timing measurements but not for metrics of perturbation-periodicity or other frequency-related measurements (16–18, 25, 26). Finally, we hypothesize that despite possible differences in measurements, the consistent use any of the tested microphones would yield a similar differentiation between a group of dysarthric (mild and sub-clinical) and non-dysarthric speakers.…”

Section: Introductionmentioning

confidence: 83%

“…We selected a high-quality configuration previously used in speech research as the reference microphone, consisting of an AKG C520 head-worn cardioid condenser microphone coupled to a Roland Duo Capture EX USB Audio Interface and connected to a laptop. Characteristics of this microphone include a sensitivity of 5mV/Pa, a near flat tonal frequency response, a condenser transducer type, cardioid pattern, and mount positioning close to sound source, which are considered adequate for recording speech for acoustic analysis according to various reference authors (22, 26–28). Consumer grade microphones included three configurations of the 6 th generation iPod Touch: (1) the in-built iPod Touch microphone (in-built); (2) Rode IXY-L mobile-mount cardioid condenser microphone (directional, sensitivity of 8.5mV/Pa); and (3) Sennheiser ClipMic Digital lapel omnidirectional condenser microphone (lapel, sensitivity of 5mV/Pa).…”

Section: Methodsmentioning

confidence: 99%

“…In a recent study, Awan et al compared playback speech recorded by four modern smartphones, which had similar frequency responses, and a reference microphone and observed a correlational equivalence in measured CPP but a large device-effect on measured spectral tilt (25). In a similar study testing consumer and professional-grade head-worn microphones, this time with different frequency response curves, Awan et al highlighted that differences in measured CPP were not correlated to frequency response or to microphone’s sensitivity around 100-200Hz (26) in contrast to earlier assumptions (22). Thus, frequency response alone seems insufficient to predict the accuracy of perturbation measurements.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Plug-and-play microphones for recording speech and voice with smart devices

Noffs,

Cobler-Lichter,

Perera

et al. 2023

Preprint

View full text Add to dashboard Cite

INTRODUCTIONSmart devices are widely available and capable of quickly recording and uploading speech segments for health-related analysis. The switch from laboratory recordings with professional-grade microphone set ups to remote, smart device-based recordings offers immense potential for the scalability of voice assessment. Yet, a growing body of literature points to a wide heterogeneity among acoustic metrics for their robustness to variation in recording devices. The addition of consumer-grade plug-and-play microphones has been proposed as a possible solution. The aim of our study was to assess if the addition of consumer-grade plug-and-play microphones increases the acoustic measurement agreement between ultra-portable devices and a reference microphone.METHODSSpeech was simultaneously recorded by a reference high-quality microphone commonly used in research, and by two configurations with plug-and-play microphones. Twelve speech-acoustic features were calculated using recordings from each microphone to determine the agreement intervals in measurements between microphones. Agreement intervals were then compared to expected deviations in speech in various neurological conditions. Additionally, each microphone’s response to speech and to silence were characterized through acoustic analysis to explore possible reasons for differences in acoustic measurements between microphones. Lastly, the statistical differentiation of two groups, neurotypical and people with Multiple Sclerosis, using metrics from each tested microphone was compared to that of the reference microphone.RESULTSThe two consumer-grade plug-and-play microphones favoured high frequencies (mean centre of gravity difference ≥ +175.3Hz) and recorded more noise (mean difference in signal-to-noise ≤ -4.2dB) when compared to the reference microphone. Between consumer-grade microphones, differences in relative noise were closely related to distance between the microphone and the speaker’s mouth. Agreement intervals between the reference and consumer-grade microphones remained under disease-expected deviations only for fundamental frequency (f0, agreement interval ≤0.06Hz),f0instability (f0CoV, agreement interval ≤0.05%) and for tracking of second formant movement (agreement interval ≤1.4Hz/millisecond). Agreement between microphones was poor for other metrics, particularly for fine timing metrics (mean pause length and pause length variability for various tasks). The statistical difference between the two groups of speakers was smaller with the plug-and-play than with the reference microphone.CONCLUSIONMeasurement off0and F2 slope were robust to variation in recording equipment while other acoustic metrics were not. Thus, the tested plug-and-play microphones should not be used interchangeably with professional-grade microphones for speech analysis. Plug-and-play microphones may assist in equipment standardization within speech studies, including remote or self-recording, possibly with small loss in accuracy and statistical power as observed in the current study.

show abstract

Section: Introductionmentioning

confidence: 83%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Plug-and-play microphones for recording speech and voice with smart devices

Noffs,

Cobler-Lichter,

Perera

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…We selected a high-quality configuration previously used in speech research as the reference microphone, consisting of an AKG C520 head-worn cardioid condenser microphone coupled to a Roland Duo Capture EX USB Audio Interface and connected to a laptop. Characteristics of this microphone include a sensitivity of 5 mV/Pa, a near flat tonal frequency response, a condenser transducer type, cardioid pattern, and mount positioning close to sound source, which are considered adequate for recording speech for acoustic analysis according to various reference authors [22,[26][27][28]. Consumer-grade microphones included three configurations of the 6th generation iPod Touch: (1) the in-built iPod Touch microphone (in-built); (2) Rode IXY-L mobile-mount cardioid condenser microphone (directional, sensitivity of 8.5 mV/Pa); and (3) Sennheiser ClipMic digital lapel omnidirectional condenser microphone (lapel, sensitivity of 5 mV/Pa).…”

Section: Methodsmentioning

confidence: 99%

“…In a recent study, Awan et al [25] compared playback speech recorded by four modern smartphones, which had similar frequency responses, and a reference microphone and observed a correlational equivalence in measured CPP but a large device effect on measured spectral tilt. In a similar study testing consumer and professional-grade head-worn microphones, this time with different frequency response curves, Awan et al [26] highlighted that differences in measured CPP were not correlated to frequency response or to microphone's sensitivity around 100-200 Hz in contrast to earlier assumptions [22]. Thus, frequency response alone seems insufficient to predict the accuracy of perturbation measurements.…”

Section: Introductionmentioning

confidence: 99%

Plug-and-Play Microphones for Recording Speech and Voice with Smart Devices

Noffs,

Cobler-Lichter,

Perera

et al. 2023

Folia Phoniatr Logop

View full text Add to dashboard Cite

INTRODUCTION Smart devices are widely available and capable of quickly recording and uploading speech segments for health-related analysis. The switch from laboratory recordings with professional-grade microphone set ups to remote, smart device-based recordings offers immense potential for the scalability of voice assessment. Yet, a growing body of literature points to a wide heterogeneity among acoustic metrics for their robustness to variation in recording devices. The addition of consumer-grade plug-and-play microphones has been proposed as a possible solution. Our aim was to assess if the addition of consumer-grade plug-and-play microphones increase the acoustic measurement agreement between ultra-portable devices and a reference microphone. METHODS Speech was simultaneously recorded by a reference high-quality microphone commonly used in research, and by two configurations with plug-and-play microphones. Twelve speech-acoustic features were calculated using recordings from each microphone to determine the agreement intervals in measurements between microphones. Agreement intervals were then compared to expected deviations in speech in various neurological conditions. Each microphone’s response to speech and to silence were characterized through acoustic analysis to explore possible reasons for differences in acoustic measurements between microphones. The statistical differentiation of two groups, neurotypical and people with Multiple Sclerosis, using metrics from each tested microphone was compared to that of the reference microphone. RESULTS The two consumer-grade plug-and-play microphones favoured high frequencies (mean centre of gravity difference ≥ +175.3Hz) and recorded more noise (mean difference in signal-to-noise ≤ -4.2dB) when compared to the reference microphone. Between consumer-grade microphones, differences in relative noise were closely related to distance between the microphone and the speaker’s mouth. Agreement intervals between the reference and consumer-grade microphones remained under disease-expected deviations only for fundamental frequency (f0, agreement interval ≤0.06Hz), f0 instability (f0 CoV, agreement interval ≤0.05%) and for tracking of second formant movement (agreement interval ≤1.4Hz/millisecond). Agreement between microphones was poor for other metrics, particularly for fine timing metrics (mean pause length and pause length variability for various tasks). The statistical difference between the two groups of speakers was smaller with the plug-and-play than with the reference microphone. CONCLUSION Measurement of f0 and F2 slope were robust to variation in recording equipment while other acoustic metrics were not. Thus, the tested plug-and-play microphones should not be used interchangeably with professional-grade microphones for speech analysis. Plug-and-play microphones may assist in equipment standardization within speech studies, including remote or self-recording, possibly with small loss in accuracy and statistical power as observed in this study.

show abstract