Shure (OEM) Spec 2

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Title: Shure OEM Spec 2Introduction:This document provides the specifications for the second version of Shure original equipment manufacturer (OEM) microphone capsules in accordance with Shure's internal design standards. These specifications cover electrical, mechanical, and acoustical aspects of the product and provide requirements for materials, testing, and measurement.Electrical Specifications:1. Polarity: Positive pressure on the diaphragm results in a positive voltage on the output pin.2. Output Impedance: 100 ohms ±10%.3. Maximum Output Level: 1.1 volts RMS at a frequency of 1,000 Hz, impedance in the low impedance configuration no greater than 100 ohms or, in the high impedance configuration, no greater than 400 ohms.4. Equivalent Noise Level (EIN): Less than -127 dBV with a bandwidth of 1 Hz at a temperature of 23 degrees Celsius with a low-noise preamp provided to the capsule input.5. Frequency Response:- Low Impedance Configuration: Within ±1.5 dB from 20 Hz to 20 kHz at a distance of 5 millimeters from the capsule's center.- High Impedance Configuration: Within ±3 dB from 20 Hz to 20 kHz at a distance of 5 millimeters from the capsule's center.6. Common Mode Rejection Ratio (CMRR):- Low Impedance Configuration: Greater than 70 dB from 50 Hz to 8 kHz.- High Impedance Configuration: Greater than 55 dB from 50 Hz to 8 kHz.Mechanical Specifications:1. Diameter: 14 millimeters + 0/- 0.1 millimeters.2. Overall Length: 14.6 millimeters + 0/- 0.1 millimeters.3. Weight (Without French Fit Mount): Less than 1 gram.4. Diaphragm Diameter: 6 millimeters + 0/- 0.1 millimeters.5. diaphragm Material: 1 micron thickness PVDF (Polyvinylidene Fluoride) membrane.6. Backplate Material: Nickel-plated brass.7. RFI Shielding: Conformal coating applied to protect against ESD, RFI, and humidity ingress.Acoustical Specifications:1. Frequency Response: See Electrical Specifications.2. Polar Patterns:- Cardioid: Frequency response varies by azimuth and offset angle relative to the diaphragm center axis. - With the cardioid response aligned within ± 5-degrees of the front, the frequency response is omnidirectional above ±90-degrees from the front and 6 dB down in cardioid response below ±90-degrees from the front. Within this zone, the azimuth response varies ±2 dB.- Hypercardioid: Frequency response varies by azimuth and offset angle relative to the diaphragm center axis. Frequency response is uniform across both the back and front hemispheres with the maximum sensitivity at the center of the front hemisphere, where the response is flat within ±1.5 dB. The response is less sensitive to angles between ± 20-degrees and ± 160-degrees from the center axis, where the response is flat within ±2.5 dB. The response is less sensitive to angles between ± 160-degrees and ± 200-degrees from the center axis, where the response is flat within ±3.5 dB.Testing and Measurement:1. All microphone capsules shall be 100% tested during acceptance and final production inspection using automated instruments and specific Shure test fixtures.2. The maximum permissible voltage rating for the OEM capacitor is 50 volts RMS for a duration of 4 hours with lifetime duty cycles between 15 and 30 hours.3. The conductivity of the diaphragm material shall meet a minimum value of 10^16ohm-cm (1 Ω-cm).4. The distance from top/center point of the gold-plated pin to the diaphragm shall not exceed ±1.0 millimeters, measured directly or diagonally.5. Touch-proof voltage rating of the backplate and body contacts (base) ought to be more than 750 volts at 60 Hz for a duration of 1 minute without any permanent damage on these components.6. Every OEM capacitor undergoes a 15-minute high-temperature, open-circuit leakage test; for this process, a voltage source near 300 Volts DC will be applied through the terminal pin of the OEM capacitor. This test is meant to evaluate the capacitor's hermeticity conditions under corresponding high-temperature processing. The capacitor's hermeticity will be tested during incoming inspection and final production