GRAS EQ 40PM EQset™ Micrô cho dây chuyền sản xuất

1. Introduction

EQ 40PM with EQset is designed for use in production line environments, and it provides many benefits over traditional production line- or array-style microphones. Designed to be cost-effective, easy to use, resistant to errors, and environmentally stable, EQ 40PM is the best production line microphone option on the market. Each EQ 40PM microphone has a flat response curve and fixed sensitivity. The tolerance for individual microphone sensitivities is less than ±0.2 dB, and frequency-response variation is less than ±0.5 dB up to 10 kHz. And because EQ 40PM is dimensionally identical to the traditional production line microphones, it can easily replace them in existing setups.

EQset technology

EQset microphones all have a uniformly fixed sensitivity and flat curve. This reduces measurement uncertainty and greatly simplifies microphone setup, monitoring, replacement, and corrections. EQset means that everything can happen quickly and easily without any individual microphone adjustments or corrections. The simplification of setup and other tasks saves both time in the setup itself and time in operator training. There is, however, one additional benefit that outshines the time savings: EQset all but eliminates the inherent risk of false passes on production lines or correction error for frequencies outside the calibrated frequency in R&D—common issues with other microphones in the market.

Another benefit of the uniformly fixed sensitivity and flat response curve of each EQset microphone is that because there is no need to make individual corrections for each microphone, there is, therefore, no need to store that correction information on the microphones via TEDS. This enables EQset microphones to be used effectively with systems based on audio sound cards using 48 V phantom power as well as any CCP-based system already in use, so there is no need for price-prohibitive new equipment or retooling of existing CCP-based systems.

Environmental stability

The unique design of the EQ 40PM provides this range of microphones with unmatched environmental stability. The deviation on a typical production line is less than ±0.3 dB, so there is no need for corrections due to temperature or humidity over the course of a normal day in a typical production-line environment.

Typical applications and use

Production-line testing of audio devices such as drivers, receivers, micro-speakers, and miniature microphones
Measurements in confined spaces

When starting up, these microphones have a settling time of approximately 5 seconds for accuracy better than 0.1 dB or 1 minute for full accuracy.

2. Key Features

2.1. Design

The GRAS EQ 40PM is a robust, cost-effective microphone designed for use in production line testing of loudspeakers and acoustic transducers. It has a wide frequency range, from 20 Hz to 20 kHz, and a dynamic range from 30 dB (A) to 120 dB.

The cost-effectiveness of the EQ 40PM is a key consideration when setting up multiple production lines. Each EQ 40PM is interchangeable with any other EQ 40PM without the need for recalibration or additional corrections.

EQ 40PM is a 34 mm long ¼″ microphone that can be used in space-challenged setups where larger microphones would not fit or provide difficulties in testing. Additionally, its small aperture provides an advantage in testing micro-speakers, or miniature microphones. It is good practice to use a microphone with a diameter similar to or smaller than the device to be measured.

2.2. Compability

This range of microphones is fully compatible with 48 V phantom power setups and CCP-based setups. As such the EQ 40PM can be used in new cost-saving production-line setups or as replacements for less accurate TEDS-based microphones in existing CCP setups.

Using a phantom power setup along with an analyzer such as the APx500 Flex Audio Analyzer will create a budget-friendly setup that can be expanded or upgraded easily as need arises.

2.3. Calibration - measurement chain

GRAS EQ 40PM microphones can be calibrated to ensure that down-stream equipment (such as a sound card) is correctly set up using a pistonphone like GRAS 42AP or a hand-held calibrator like the GRAS 42AG Multifunction Sound Calibrator.

2.4. Quality and Warranty

GRAS microphone sets are made of components from our proven standard portfolio and are all manufactured of high-quality material and branded parts that were chosen and processed to ensure life-long stability and robustness.

All parts are manufactured and assembled at the factory in Denmark by skilled and dedicated operators.

Thanks to the high quality, our warranty against defective materials and workmanship is two years.

3. Specifications


Polarization/Connection	0 V / CCP
Pressure response (±0.5 dB)	20 Hz to 10 kHz
Frequency range (±2 dB)	10 kHz to 20 kHz
Dynamic range w/ GRAS CCP preamplifier	30dB (A) to 120dB
Sensitivity	25 mV/Pa (250Hz, ±0.2 dB)
Output impedance	< 50 Ω
Output Voltage Swing, min. @ 24-28 V CCP voltage supply	8 Vp
Power supply min. to max.	4 to 10 mA
Power supply min. to max. (single/balanced)	N/A
DC bias voltage, typ.	13.7 V ±0.5
Microphone venting	Front
IEC 61094-4 Designation	WS2P
Temperature range, operation	-10 to 55 °C
Temperature range, storage	-25 to 70 °C
Humidity range non condensing	0 to 90 % RH
Connector type CE/RoHS compliant/WEEE registered Weight	SMB Yes/Yes/Yes 3.5 g
Max cable length	10m (at 4mA)