The Impact of Mobile Phone Quality on External Microphone Performance

In the era of mobile recording, the importance of the external microphone quality cannot be overstated. However, it is equally crucial to understand how the quality of your mobile device affects the overall performance. Let's delve into the nuances of this relationship.

Understanding Modern Microphones

Modern microphones, particularly those designed for mobile devices, are electret types. These microphones derive a small charge of power (1.5–3v) directly from the device via the 3.5mm headphone jack. This design, known as electret, allows for fairly good frequency response output, making them versatile for various audio recording needs.

When it comes to choosing the right microphone, the frequency response is a key metric to consider. It is important to examine the lowest frequency as well as the highest frequencies, including Bass, Middle, and Top ranges. Many modern phones use a 4-pin TRRS jack for their microphones, while others may have proprietary connectors like the lightning port on iPhones. These phones typically require a converter to enable the use of a 3.5mm TRRS microphone.

While the microphone itself can be of high quality, the quality of the a/d converter within the mobile device can still play a significant role. This means that even if the microphones are the same, the output sound might still differ based on the device's internal components.

Example: If you attach the same external microphone to a Samsung J3 and an iPhone 7, the difference in a/d converter quality might make the sound experience noticeably different. Even though the microphone is the same, the phone’s internal components can enhance or degrade the audio quality significantly.

Designing for Professional Audio

For professional use, such as in broadcasting, it is often necessary to design and build solutions using a mobile phone as a backup or replacement. In these cases, it is crucial to ensure that the microphone is connected to a professional XLR box with balancing transformers, which offers far better preamplifier quality.

It is also important to note that not all cables available in the domestic market are designed to the same standards. Often, these cables can be cheap and may not follow the correct wiring codes. As a result, some phones have to utilize the screen as a microphone, which is functional but not ideal. In such cases, the screen may need to be wrapped around wires to mitigate interference, which can affect the overall audio quality.

Direct Input vs. Cables

A significant difference between professional audio recording devices and mobile phones is the presence of XLR sockets and a more robust 3.5mm input with a Line/Mic switch. These professional devices also feature far better preamplifiers. Therefore, a microphone that is prewired with a 3.5mm jack plug can reveal the differences in the preamplifier between one device and another.

It is difficult to audibly detect differences in the quality of the microphone alone. Bench tests and oscilloscope comparisons of the output stage can help reveal differences in the signal-to-noise ratio and frequency response. However, for most everyday users, these nuanced differences are not easily noticeable in real-world scenarios.

In conclusion, while the quality of the external microphone is important, the quality of the mobile device itself also plays a significant role. Understanding the differences and making informed decisions can lead to the best possible audio recording experience.