The Raspberry Pi, a versatile and affordable single-board computer, has gained immense popularity in various applications, from DIY projects to industrial solutions. However, use case of creating product for urban noise monitoring on one hand and podcasting on the other may have completely different requirements in terms of audio solution budget, size and performance. Choosing the right microphone for your Raspberry Pi is crucial, as it directly impacts the quality of audio input for your projects. This is why in this article, we will explore the different types of microphones, their applications, and key considerations for selecting the ideal microphone for your Raspberry Pi.
Before delving into different types of microphones let us take a moment to note two important things. First one is the fact that Raspberry Pi does not posses any analog inputs. Second one is that microphones do come in two flavors: analog and digital. That is why if you need to interface with analog microphones, you can use external ADCs to convert analog signals to digital signals that the Raspberry Pi can read. There are various ADCs available that can be connected to the GPIO pins, either through the I2C, SPI, or other communication interfaces. For learning more about connecting sensors to Raspberry Pi, refer to this blog post.
Types of Microphones
As mentioned before, different types of microphones exist and they may serve completely different purpose to varying audience type. Microphones for general purpose use cases such as recording may differ compared to the small electronic component type of microphones used in engineering projects. We will make sure to address them all.
1. USB Microphones
USB microphones are popular choices for Raspberry Pi projects due to their simplicity and plug-and-play nature. They connect directly to the USB port, eliminating the need for additional hardware or drivers. USB microphones come in various designs, including desktop and handheld models, making them versatile for different applications.
Applications:
- Podcasting
- Voice recognition projects
- Video conferencing
- Home automation systems
Our Picks:
KISEER 2 Pcs USB 2.0 Mini Microphone
Plug and Play solution advertised by the manufacturer as the smallest USB microphone available on the market today, ideal when size is an issue.
This is an affordable solution providing studio recording quality, ideal for podcasting, recording, YouTube and the like. High sample rate (192k) and large dynamic range (24 bits), USB 2.0 compatibility, omnidirectional recording and light weight are qualities that make this microphone a good choice.
Behringer BIGFOOT All-in-One USB Condenser Microphone for Studio
This microphone with above-average frequency response and built-in USB interface is ideal for vocals, podcasters, field recordings, home studio sessions, conference calls and more. Note that price is more of a mid-range one.
Shure MV7 USB Podcast Microphone
This microphone is definitely on a higher end when it comes to price but its capabilities and the numerous awards it received justify the price. It provides options of both analog (XLR) and digital (USB) recording. It features an intuitive touch panel for easy control over gain, monitoring volume, and more. With a built-in headphone output for direct monitoring, it ensures rich and natural vocal reproduction and comes with the ShurePlus MOTIV Desktop Application for audio processing and customization. The rugged all-metal construction enhances reliability.
2. Electret Condenser Microphones
Electret condenser microphones are widely used for their sensitivity and low cost. They require a power source, typically provided through a biasing circuit, making them compatible with the Raspberry Pi's GPIO pins. Electret microphones offer good audio quality for various applications.
Applications:
- Audio recording and streaming
- Surveillance systems
- Environmental monitoring
Our Picks:
Electret Microphone Amplifier Module MAX4466
The MAX4466 microphone breakout is a versatile component ideal for voice converters, audio recording, and FFT-based projects, featuring a gain adjustment range from 25x to 125x. With a power supply voltage of +2.4V to +5.5V, it is compatible with various development boards, including STM and Raspberry Pi. The breakout board, which includes a 20-20KHz electret microphone, offers easy integration, requiring simple connections and supports a power supply noise rejection function for reliable performance.
Adafruit Electret Microphone Amplifier - MAX9814
This electret microphone amplifier features automatic gain control, ideal for recording or detecting audio in dynamic environments. It easily integrates with ADCs supporting inputs up to 3.3V for versatile compatibility.
3. MEMS Microphones
Micro-Electro-Mechanical Systems (MEMS) microphones are compact, low-power devices that use semiconductor manufacturing techniques. They are suitable for applications where size and power consumption are critical factors. MEMS microphones are often integrated into electronic devices such as smartphones, cameras, and IoT devices.
MEMS microphones play a crucial role in noise sensors. The shift in the industry has happened from electret to MEMS microphones due to their superior acoustic performance, compact size, reliability, durability, and cost-effectiveness. MEMS microphones consist of a sensor (MEMS sensor) and integrated circuits, offering versatility with analog or digital outputs. The acoustic performance of MEMS depends on factors like the location of the sound inlet, with bottom configuration generally providing better results. Additionally, considerations such as frequency weighting, frequency equalization, and calibration are crucial for accurate noise measurement. MEMS microphones are sensitive to environmental conditions, and factors like temperature, humidity, and wind can impact their performance, necessitating careful evaluation and potential corrections. Despite challenges, ongoing developments aim to enhance MEMS microphone capabilities, making them promising for high-performance noise sensors in the future.
Applications:
- Wearable technology
- Compact audio recording devices
- Noise-cancelling applications
Our Picks:
Adafruit I2S MEMS Microphone Breakout - SPH0645LM4H (3421)
This MEMS microphone stands out for its compact size, being smaller and thinner than traditional electret microphones. Offering a cost-effective solution, it operates purely in the digital domain, eliminating the need for analog conversion, and provides a frequency range of approximately 50Hz to 15KHz, making it suitable for various general audio recording and detection applications.
INMP441 Omnidirectional Microphone Module MEMS I2S Interface
The INMP441 is a top-performing, low-power, omnidirectional MEMS microphone with a bottom port design. Equipped with MEMS sensors, analog-to-digital converters, anti-aliasing filters, and an industry-standard 24-bit I2S interface, it can be directly connected to digital processors like DSPs and microcontrollers without requiring additional audio codecs. With a high signal-to-noise ratio of 61dBA and a flat broadband frequency response, the INMP441 excels in near-field applications, delivering exceptional sound clarity.
Raspberry Pi Audio HATs
Raspberry Pi HATs, or Hardware Attached on Top, are expansion boards designed to precisely fit onto the Raspberry Pi's GPIO pins, providing additional functionalities, sensors, or interfaces. HATs streamline hardware integration, allowing users to extend the capabilities of their Raspberry Pi without complex wiring or soldering.
Audio HATs specifically focus on enhancing the audio capabilities of the Raspberry Pi. These HATs often come equipped with features like audio input/output interfaces, amplifiers, and enhanced signal processing. Due to this, they may be ideal solution when dealing with projects involving audio signals recording and processing.
Our Picks:
This audio-focused extension board features a standard Raspberry Pi 40PIN GPIO header, making it compatible with various Raspberry Pi series boards. It incorporates the WM8960 low-power stereo CODEC for communication via the I2S interface. The board includes dual high-quality MEMS silicon microphones, enabling dual-channel recording for superior sound quality. With an onboard 3.5mm earphone jack, users can enjoy music through external earphones. Additionally, it provides a dual-channel speaker interface for driving speakers directly and supports various sound effects such as stereo and 3D surrounding. The package includes development resources and a manual, along with Python demo code for playing and recording audio.
RASPIAUDIO Audio DAC Hat Sound Card
This audio board is equipped with two onboard microphones and supports stereo input through a 3.5mm LINE jack. It features stereo onboard speakers and a 24-bit I2S DAC with a 2x1.3W stereo amplifier for external speakers. The board also provides a headphone output with 24-bit audio support.
Considerations for Choosing a Microphone
1. Compatibility
Ensure that the microphone you choose is compatible with the Raspberry Pi. USB microphones are generally plug-and-play, while other types may require additional hardware or software configurations.
2. Sensitivity and Directionality
Consider the sensitivity and directionality of the microphone based on your project requirements. Omnidirectional microphones capture sound from all directions, while unidirectional microphones focus on a specific direction.
3. Power Requirements
Different microphones have varying power requirements. Check if the microphone can be powered directly from the Raspberry Pi or if an external power source is needed.
4. Noise Handling
Evaluate the microphone's ability to handle ambient noise and interference, especially in noisy environments or projects that require precise audio input.
5. Form Factor
Choose a microphone with a form factor that suits your project. For portable projects, smaller and more compact microphones may be preferable.
6. Budget
Consider your budget constraints, as microphones come in a wide price range. Balance cost with the required features and performance for your specific application.
Conclusion
Choosing the right microphone for your Raspberry Pi project is a critical step in ensuring high-quality audio input. Evaluate the type, compatibility, sensitivity, and other factors to determine the best fit for your application. Whether you are building a voice-controlled assistant or a multimedia center, selecting the appropriate microphone will greatly enhance the overall functionality and user experience of your Raspberry Pi project.