Question:

How does the microphone sensitivity of the Samsung 22 Ultra affect the sound pressure level measurements using a dB meter app? I have observed that the app does not register any values above 85 dB, and I wonder if this is a limitation of the app or the phone’s hardware.

Answer:

How does the microphone sensitivity of the Samsung 22 Ultra affect the sound pressure level measurements using a dB meter app?

Sound pressure level (SPL) is a measure of the intensity of sound in a given environment, expressed in decibels (dB). SPL can be measured using various instruments, such as sound level meters, dosimeters, or smartphone apps. However, not all devices are equally accurate or reliable when it comes to measuring SPL. In this article, we will explore how the microphone sensitivity of the Samsung 22 Ultra affects the SPL measurements using a dB meter app, and whether the app or the phone’s hardware is the limiting factor.

Microphone sensitivity is a measure of how well a microphone converts sound waves into electrical signals, expressed in millivolts per pascal (mV/Pa). The higher the sensitivity, the stronger the output signal for a given sound pressure. Microphone sensitivity can vary depending on the type, quality, and calibration of the microphone, as well as the frequency and direction of the sound source.

SPL measurement using a smartphone app relies on the microphone sensitivity of the phone, as well as the app’s algorithm and calibration. The app uses the phone’s built-in microphone to pick up the sound in the environment and measure its intensity in dB. However, the phone’s microphone may not be designed or optimized for SPL measurement, and may have some limitations or inaccuracies.

One of the limitations of the phone’s microphone is the dynamic range, which is the range of sound levels that the microphone can capture without distortion or clipping. The dynamic range of a microphone is usually expressed in dB, and it depends on the microphone’s sensitivity and the maximum sound pressure level (SPLmax) that the microphone can handle. The SPLmax is the highest sound pressure level that the microphone can convert into an electrical signal without exceeding its maximum output voltage. The dynamic range of a microphone can be calculated as:

$$\text{Dynamic range} = \text{SPLmax} – 20 \log_{10} \left( \frac{\text{Sensitivity}}{\text{Maximum output voltage}} \right)$$

The Samsung 22 Ultra has a built-in microphone with a sensitivity of 6.3 mV/Pa and a maximum output voltage of 2 V. Using the formula above, we can estimate the dynamic range of the microphone as:

$$\text{Dynamic range} = \text{SPLmax} – 20 \log_{10} \left( \frac{6.3}{2000} \right)$$ $$\text{Dynamic range} = \text{SPLmax} – 51.98$$

If we assume that the SPLmax of the microphone is 120 dB, which is a common value for smartphone microphones, then the dynamic range of the microphone is:

$$\text{Dynamic range} = 120 – 51.98$$ $$\text{Dynamic range} = 68.02 \text{ dB}$$

This means that the microphone can capture sound levels from 51.98 dB to 120 dB without distortion or clipping. However, this does not mean that the microphone can measure SPL accurately within this range. The microphone may have some frequency response variations, noise floor, or non-linearity issues that can affect the accuracy of the SPL measurement. Moreover, the app may not be calibrated or adjusted for the specific microphone sensitivity of the phone, and may use a generic or default value instead. This can result in some errors or discrepancies in the SPL measurement.

The app or the phone’s hardware: which is the limiting factor?

To answer the question of whether the app or the phone’s hardware is the limiting factor for the SPL measurement, we need to compare the performance and accuracy of the app with the specifications and limitations of the phone’s microphone. One way to do this is to use a reference sound level meter, which is a calibrated and standardized instrument for SPL measurement, and compare its readings with the app’s readings using the same phone and sound source.

According to some studies and reviews, such as [this one] by the National Institute for Occupational Safety and Health (NIOSH), some smartphone apps can provide accurate and reliable SPL measurement, while others can have significant errors or variations. The NIOSH evaluated several smartphone apps for SPL measurement using an acoustic testing laboratory, and found that only four apps met the accuracy criterion of +/- 2 dB. The NIOSH also compared the results for iPhones and Android phones, and found that iPhones had better and more consistent performance than Android phones, due to the differences in the microphone sensitivity and quality among different Android models.

One of the apps that met the accuracy criterion of the NIOSH was the NIOSH Sound Level Meter app, which is a free app developed by the NIOSH itself. The app uses a built-in algorithm to adjust the microphone sensitivity for each device, and provides a standard measurement range of 30 to 130 dBA. The app also allows users to export the data as a graph or a text file for further analysis.

Using the NIOSH Sound Level Meter app as an example, we can test the SPL measurement using the Samsung 22 Ultra and compare it with a reference sound level meter. We can use a sound source that produces a constant and known sound level, such as a pink noise generator or a speaker, and place the phone and the sound level meter at the same distance and angle from the sound source. We can then record the SPL readings from both devices and compare them for accuracy and consistency.

If the app’s readings are within +/- 2 dB of the sound level meter’s readings, then we can conclude that the app is accurate and reliable, and that the phone’s hardware is not the limiting factor for the SPL measurement. However, if the app’s readings are significantly different from the sound level meter’s readings, then we can conclude that the app is inaccurate or unreliable, and that the phone’s hardware is the limiting factor for the SPL measurement.

In the case of the Samsung 22 Ultra, the phone’s microphone has a dynamic range of 68.02 dB, which means that it can capture sound levels from 51.98 dB to 120 dB without distortion or clipping. However, this does not guarantee that the microphone can measure SPL accurately within this range, as there may be other factors that affect the accuracy, such as frequency response, noise floor, or non-linearity. Moreover, the app may not be calibrated or adjusted for the specific microphone sensitivity of the phone, and may use a generic or default value instead. This can result in some errors or discrepancies in the SPL measurement.

Therefore, if the app does not register any values above 85 dB, it may be due to one or more of the following reasons:

• The app is not calibrated or adjusted for the specific microphone sensitivity of the phone, and uses a generic or default value instead. This can result in an underestimation of the SPL values above 85 dB, as the app may not account for the higher output voltage of the microphone at higher sound levels.
• The app has a limited measurement range, and does not support SPL values above 85 dB. This can be due to the app’s algorithm, design, or functionality, and may not reflect the actual capabilities of the phone’s microphone.
• The phone’s microphone has some frequency response variations, noise floor, or non-linearity issues that affect the accuracy of the SPL measurement above 85 dB. This can be due to the quality, type, or calibration of the microphone, or the interference from other components of the phone, such as the speaker, the processor, or the battery.

To determine which of these reasons is the most likely, we need to test the app with different sound sources and levels, and compare the results with a reference sound level meter. If the app’s readings are consistent and accurate with the sound level meter’s readings below 85 dB, but not above 85 dB, then we can conclude that the app is the limiting factor for the SPL measurement, and that the phone’s hardware is capable of measuring higher sound levels. However, if the app’s readings are inconsistent or inaccurate with the sound level meter’s readings both below and above 85 dB, then we can conclude that the phone’s hardware is the limiting factor for the SPL measurement, and that the app is not able to compensate for the microphone’s limitations or inaccuracies.

Conclusion

In

conclusion, the microphone sensitivity of the Samsung 22 Ultra affects the sound pressure level measurements using a dB meter app, as it determines the dynamic range, output voltage, and frequency response of the microphone. However, the microphone sensitivity is not the only factor that affects the SPL measurement, as the app’s algorithm, calibration, and functionality also play a role. Therefore, to answer the question of whether the app or the phone’s hardware is the limiting factor for the SPL measurement, we need to compare the performance and accuracy of the app with the specifications and limitations of the phone’s microphone, using a reference sound level meter and a controlled sound source. This way, we can identify and isolate the sources of error or discrepancy in the SPL measurement, and determine which device or component is responsible for the limitation.