I. Overview
The MegaSig AM 581 is an artificial mouth simulator conforming to ITU-T Recommendation P.51 and the international standards IEEE 269 and IEEE 661. Its main function is to accurately simulate the sound field distribution of a human mouth in the near field. It is primarily used to test the frequency response and distortion of acoustic parameters such as those of telephone transmitters, various microphones, and communication terminals, and is a key component in building standardized electroacoustic testing systems.
Its design goal is to provide a stable standard sound pressure level output while maintaining extremely low distortion, suitable for laboratory R&D verification and production line testing of high-end audio products. Below, we will explain it from the perspectives of specifications and applications:
II. Core Functions and Technological Advantages of the Product
The AM 581 is designed with high sensitivity and wide bandwidth transduction efficiency in mind. Its core technological advantages are reflected in the following data indicators:
1. Excellent low distortion performance
- At a typical test distance, i.e., 8cm from the mouth reference point (MRP), when outputting a sound pressure level of 94dB SPL, the total harmonic distortion (THD) is less than 1% in the frequency band from 200Hz to 10kHz .
- Even at a working distance of 10cm, it can maintain an extremely low level of distortion, ensuring the purity of the test signal and avoiding the influence of nonlinear distortion of the excitation source itself on the measurement results.
2. Stable frequency response and output capability
- Frequency response curve: In the range of 100Hz – 10kHz, the compensated output sound pressure level can be stably controlled at 94dB ± 0.1dB .
- Power handling: Impedance of 4 ohms, supporting a continuous maximum power input of 10W . Sufficient dynamic headroom is available for high SPL testing at typical test distances.
3. Physical structure conforming to international standards
- Sound outlet diameter: 20mm, strictly following the physical dimensions of a simulated artificial mouth opening.
- Lip ring design: Equipped with a lip ring with an outer diameter of 48mm and a height of 11mm to ensure the accuracy of test distance positioning and that the sound field boundary conditions meet the requirements of ITU-T P.51.
- Connector: It adopts a universal BNC interface, which is convenient for connecting to various power amplifiers or audio analyzers.
III. Usage Scenarios
The AM 581 is suitable for various electroacoustic testing scenarios that require a “standard speech source”:
- Communication terminal sending direction test: used to test the frequency response, sensitivity and noise suppression capability of the microphone of devices such as smartphones, traditional telephone handsets, and walkie-talkies.
- Electroacoustic component testing: As a standard sound source, frequency response and distortion scanning were performed directly on electret microphones (ECM) and MEMS microphone units.
- High-end audio product testing and R&D: Microphone array testing for Bluetooth headsets and smart speakers to verify their sound pickup consistency. Combined with the MegaSig PM series audio analyzer, it can form a complete excitation and acquisition system.
IV. Specifications
| Overall parameters | |
| Distortion | 200Hz – 10kHz: Factory standard less than 1% (94dB SPL, at 80mm MRP) |
| Frequency response curve | After compensation, the output sound pressure level is 94dB ± 0.1dB (100Hz – 10kHz) |
| Impedance | 4ohm |
| Continuous maximum power | 10W |
| Sound aperture | Φ20mm |
| Lip ring | Outer diameter: Φ48 mm Height: 11mm |
| Diameter | Φ104mm |
| High | 100mm |
| Weight | 1276g |
| interface | BNC |
Compensated 94 dBSPL Frequency Response Curve @ 80mm MRP
Compensated 94 dBSPL Typical Distorsion Curve @ 80mm MRP
V. Conclusion
If you are looking for a test source that accurately reproduces the characteristics of human vocalization and fully complies with IEEE and ITU-T international standards, the MegaSig AM 581 is currently the most cost-effective option on the market. Years of customer experience have further proven its excellent long-term operational stability. Whether for precise analysis during the R&D phase or for consistency control during the production line phase, the AM 581 provides a solid physical foundation for your acoustic testing.
If you require further planning consultation for your project, please feel free to contact us for technical exchange.