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MAX9814 High-Performance Microphone Amplifier Module with AGC

SKU: FA3020-4
Module Type

Microphone amplifier with AGC
Amplifier IC

MAX9814
Sensor Type

Electret condenser microphone
Operating Voltage

2.7V – 5.5V DC
Gain Settings

40dB / 50dB / 60dB (selectable)
Output Type

Analog (audio waveform)
Output Noise

40µV typical
Pin Count

4 pins (VCC, GND, OUT, GAIN)

The MAX9814 High-Performance Microphone Amplifier Module is a compact, professional-grade audio preamplifier board designed for Arduino, Raspberry Pi, ESP32, and other microcontroller projects. Built around the MAX9814 IC from Maxim Integrated (now Analog Devices), this module features Automatic Gain Control (AGC) and a built-in electret microphone, delivering clean, consistent audio amplification across a wide range of sound levels. It is an ideal solution for sound level meters, voice recording, clap detection, audio spectrum analyzers, and audio-reactive projects.

At the heart of the module is the MAX9814, a high-performance microphone amplifier with programmable gain, automatic gain control, and a low-noise bias voltage generator for the electret microphone. The AGC function automatically adjusts the amplification level based on the input signal strength — when the sound is quiet, the gain increases; when the sound is loud, the gain decreases. This ensures that the output signal remains within a usable range without clipping or distortion, making the module far more forgiving than fixed-gain amplifiers like the MAX4466.

The MAX9814 offers three selectable gain settings — 40dB, 50dB, and 60dB — configurable via the GAIN pin. Additionally, the Attack/Release Ratio can be set to 1:4000, 1:2000, or 1:500 via the A/R pin, allowing you to fine-tune the AGC response for different applications. The Attack Time is fixed at 30µs, while the Release Time varies based on the A/R setting. The AGC Threshold is internally set to 1.25V, with a hold time of 2.5ms to prevent rapid gain fluctuations.

The module outputs an analog voltage on the OUT pin that follows the audio waveform, centered at approximately VCC/2. This output connects directly to your microcontroller’s ADC pin, allowing you to sample the audio in real time. The low output noise (typically 40µV) and high PSRR make the module suitable for sensitive audio applications.

The module operates from a 2.7V to 5.5V DC supply, making it compatible with both 3.3V and 5V microcontrollers. The compact form factor with mounting holes allows easy integration into custom enclosures, portable devices, and sound-reactive projects. The 4-pin interface (VCC, GND, OUT, GAIN) provides simple, straightforward wiring.

The MAX9814 Audio Amplifier Module is widely used in sound level meters, clap detectors, voice-activated projects, audio spectrum analyzers, noise monitoring systems, interactive art installations, and educational STEM projects. It is also popular in DIY electronics and maker projects where clean, automatic audio amplification is required.

Important Note: The MAX9814 amplifies the audio waveform, not just the sound level. The output is an analog signal that follows the audio waveform, so your microcontroller must sample it fast enough (typically 1kHz–10kHz) to capture the signal accurately. The AGC function makes the module ideal for environments with varying sound levels, but for precise absolute sound level measurement, a fixed-gain amplifier like the MAX4466 may be preferred. The module is not waterproof and should be kept dry.

Whether you are building a sound level meter, a voice recorder, or an audio-reactive LED display, the MAX9814 Audio Amplifier Module provides a reliable, professional-grade solution with automatic gain control. It is suitable for individual makers, students, and businesses purchasing in bulk for product development or educational programs.

Features

  • MAX9814 microphone amplifier IC — High-performance with automatic gain control (AGC)

  • Built-in electret microphone — Captures ambient sound accurately

  • Automatic Gain Control (AGC) — Adjusts gain automatically based on sound level

  • Selectable gain — 40dB, 50dB, or 60dB via GAIN pin

  • Selectable Attack/Release ratio — 1:4000, 1:2000, or 1:500 via A/R pin

  • Low output noise — Typically 40µV for clean audio

  • Analog output — Direct connection to microcontroller ADC pins

  • Wide voltage range — 2.7V to 5.5V DC, compatible with 3.3V and 5V systems

  • Compact form factor — With mounting holes for easy integration

  • Wide application range — Sound level meters, clap detectors, voice recording, audio visualization

Technical Specifications 

# Parameter Specification
1 Module Type Microphone amplifier with AGC
2 Amplifier IC MAX9814
3 Sensor Type Electret condenser microphone
4 Operating Voltage 2.7V – 5.5V DC
5 Gain Settings 40dB / 50dB / 60dB (selectable)
6 Output Type Analog (audio waveform)
7 Output Noise 40µV typical
8 Pin Count 4 pins (VCC, GND, OUT, GAIN)

Usage

Getting Started

  1. Connect power — Supply 2.7V to 5.5V DC to the VCC pin and GND to ground.

  2. Connect the output — Connect the OUT pin to an analog input pin on your microcontroller (e.g., A0 on Arduino).

  3. Set the gain — Connect the GAIN pin to GND, VCC, or leave floating to select 40dB, 50dB, or 60dB respectively.

  4. Set the Attack/Release ratio — Connect the A/R pin to GND, VCC, or leave floating to select 1:4000, 1:2000, or 1:500 respectively.

  5. Upload a test sketch — Sample the analog output at a high rate (e.g., 1kHz–10kHz) and observe the values change with sound.

  6. Implement processing — Calculate peak-to-peak amplitude, RMS, or perform FFT analysis to extract useful information from the audio signal.

Pin Connections

Module Pin Function
VCC Power (2.7V–5.5V)
GND Ground
OUT Analog audio output
GAIN Gain select (GND=40dB, VCC=50dB, Float=60dB)

Gain and A/R Configuration

GAIN Pin Gain Setting
GND 40dB
VCC 50dB
Floating 60dB
A/R Pin Attack/Release Ratio
GND 1:4000
VCC 1:2000
Floating 1:500

Example Arduino Code (Sound Level Measurement)

cpp
#define MIC_PIN A0

void setup() {
  Serial.begin(9600);
}

void loop() {
  int signalMax = 0;
  int signalMin = 1023;

  // Sample for 50ms
  unsigned long start = millis();
  while (millis() - start < 50) {
    int sample = analogRead(MIC_PIN);
    if (sample > signalMax) signalMax = sample;
    if (sample < signalMin) signalMin = sample;
  }

  int peakToPeak = signalMax - signalMin;
  Serial.print("Peak-to-Peak: ");
  Serial.println(peakToPeak);

  delay(200);
}

Typical Applications

  • Sound level meters — Measure ambient noise in decibels

  • Clap detectors — Trigger actions with hand claps

  • Voice-activated projects — Start recording or activate devices with sound

  • Audio visualization — Drive LED strips or displays with sound-reactive effects

  • Noise monitoring — Track sound levels over time

  • Voice recording — Capture audio for storage or transmission

  • Frequency analysis — Perform FFT to identify dominant frequencies

  • Educational STEM projects — Teaching audio amplification and signal processing

Notes for Business Buyers

  • Automatic Gain Control — Ideal for environments with varying sound levels, reducing the need for manual adjustment.

  • Selectable gain and A/R — Flexible configuration for different applications.

  • Low noise output — Clean audio for sensitive measurements.

  • Suitable for bulk purchasing — Ideal for sound level meter manufacturers, audio product developers, and educational institutions.

Q: What is the MAX9814 Audio Amplifier Module used for?

It is a microphone preamplifier with automatic gain control (AGC) for sound level meters, clap detectors, voice recording, audio visualization, and audio spectrum analyzers.

Q: What is the difference between MAX9814 and MAX4466?

The MAX9814 includes Automatic Gain Control (AGC) and selectable gain (40/50/60dB), while the MAX4466 has manual adjustable gain (25x–125x). The MAX9814 is better for environments with varying sound levels; the MAX4466 is preferred for precise manual control.

Q: What voltage does the module require?

It operates from 2.7V to 5.5V DC, making it compatible with 3.3V and 5V microcontrollers.

Q: How do I set the gain?

Connect the GAIN pin to GND (40dB), VCC (50dB), or leave floating (60dB).

Q: How do I set the Attack/Release ratio?

Connect the A/R pin to GND (1:4000), VCC (1:2000), or leave floating (1:500).

Q: What is the output signal?

The module outputs an analog voltage that follows the audio waveform, centered at approximately VCC/2.

Q: How do I measure sound level?

Sample the analog output at high speed (1kHz–10kHz), then calculate the peak-to-peak amplitude or RMS value to determine sound intensity.

Q: Can I use this module with a Raspberry Pi?

Yes. The Raspberry Pi has no built-in ADC, so you will need an external ADC (such as the MCP3008) to read the analog output.

Q: What is the output noise level?

The module has a typical output noise of 40µV, providing clean audio for sensitive applications.

Q: Can I purchase in bulk for a product development project?

Yes. This module is suitable for both individual users and business purchasing, including sound level meter manufacturers, audio product developers, and educational institutions.

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