4mm Omnidirectional Electret Microphone Insert for Hearing Aid

The ECM-B4015AML39-733 is a 4 × 1.5 mm omnidirectional microphone capsule suitable for high-quality hearing aids and lapel microphones. With a sensitivity of -39dB±2 and a signal-to-noise ratio of 74dB, it ensures excellent sound capture and clarity in various applications.

Model: ECM-B4015AML39-733
Dimensions: 4 × 1.5 mm
Directivity: Omnidirectional
Sensitivity: -39 dB ± 2
Impedance: 2 kΩ
S/N Ratio: 74 dB
Max SPL: 120 dB
Operating Voltage: 2 Vdc
Frequency Response: 50 Hz ~ 20 kHz
Current Consumption: 200 μA

Request Information / Sample

Tell us your project stage. Our engineering team will respond accordingly.

Lead Time

Samples: 1–3 weeks
Mass production: 2–4 weeks

Customization

Application-based engineering support
Structure / sensitivity / acoustic tuning

MOQ

3,000 pcs
Per model / per production batch

Certification

RoHS & UL compliant
Industrial reliability assured

Technical Specifications

Designed for hearing aids and lapel microphones, our 4015 omnidirectional microphone head is custom-made with high-end JFET, offering a high signal-to-noise ratio, low noise, and Hi-Fi sound quality.

Standard Test Circuit

ECM-B4015AML39-733 Standard Test Circuit: 15kΩ load, 2V supply, 1μF output

Tested with a 15kΩ load resistor, 2V DC supply, and 1μF coupling capacitor.

Typical Frequency Response

ECM-B4015AML39-733 Frequency Response Curve

Flat response from 50Hz to 5kHz, followed by a gradual decline, with a mild lift around 15kHz–20kHz that remains below the main level.

Dimensions (UNIT: mm)

Dimensions of ECM-B4015AML39-733: Φ4×1.5mm

Ultra-compact capsule measuring Φ4 × 1.5mm, with a front dustproof mesh and a sealed back structure.

Packaging Overview

Standard packaging: 100 pcs per small box.
10 small boxes (1,000 pcs) are combined into one medium carton.
Several medium cartons are further packed into a large outer carton.
Pin-type microphones are protected with foam inside the small box.
Other types are packed directly or sealed in anti-static bags.

Reliability Tests

High Temperature Test: Microphone subjected to +80℃ for 100 hours, followed by 3 hours at room temperature.

Low Temperature Test: Microphone subjected to -40℃ for 100 hours, followed by 3 hours at room temperature.

Humidity & Heat Test: Microphone exposed to +55℃ and 85% relative humidity for 100 hours, followed by 3 hours at room temperature.

Thermal Shocking Test: Microphone subjected to [+80℃ 0.5H → room temp 1H → -40℃ 0.5H → room temp 1H] for 10 cycles, then exposed to room temperature for 3 hours.

Vibration Test: Microphone subjected to two hours of vibration in x, y, and z directions with frequencies of 10-55Hz and a 1.52mm amplitude.

Drop Test: Microphone dropped 5 times from a height of 1.0 meter onto a slippery marble floor, without packaging, and still performs normally.

Storage and Operating Temperature Range: Suitable for environments ranging from -35℃ to +60℃.

Sampling Process

Confirm customer requirements:

Review product application, microphone capsule specifications, usage scenarios, and sound quality needs.

Recommend and specify:

Provide recommended microphone capsule models and detailed specifications for customer evaluation.

Sample provision and testing:

Deliver microphone samples for customer testing and feedback purposes.

Optimize and finalize:

Refine microphone design based on feedback, finalize samples, and proceed to mass production upon quality approval.

Quality Assurance

Conducting sampling inspections of incoming materials to ensure compliance with standard requirements.

Performing inspection audits to ensure the stability and control of the entire manufacturing process.

Conducting pre-shipment inspections to ensure that products meet established quality standards.

Acoustic Laboratory

Testing of background noise, sensitivity, frequency response curve, and directionality indicators.

Verification of the impact of different circuits, structural dimensions, materials, and processes on indicators.

Reliability testing at both the new product design stage and the mass production regular stage.

Automatic Workshop

Utilizing fully automated production lines to ensure high efficiency and consistency.

Equipped with state-of-the-art facilities, including a 10,000-level dust-free workshop.

Employing a rigorous 21-step process to guarantee product stability.