Danish GRAS microphone grille and windshield ball

Danish GRAS microphone grille and windshield ball

Model: AM0069

1、 Introduction to GRAS Company in Denmark:

GRAS was founded in 1994 by Gunnar Ras musen, a Danish acoustics expert and pioneer in the sound and vibration industry. As an important developer and manufacturer in the field of acoustic measurement accuracy, GRAS microphones have excellent measurement capabilities and related equipment. This includes applications and solutions for customers in aerospace, automotive, audiology, consumer electronics, and other high demand industries. The measurement microphone of GRAS microphone is developed to support key areas such as research and development, sound measurement, and production, so product testing is necessary. The GRAS microphone adopts a series of "high acceleration life tests" aimed at achieving high quality, long-term durability, and high accuracy that customers expect and trust.

Danish G.R.A.S (GRAS microphone) application range:

GRAS measurement microphones can be used in various frequency ranges, dynamic ranges, and different application scenarios.

2、 Technical data of microphone hood AM0069

AM0069 includes 5 spherical windshields, specifically designed and optimized for measuring sound pressure with a 1/2 'microphone group under free field conditions, such as when wind comes from more and unpredictable directions. The windproof cover is installed by pushing it through the microphone and preamplifier as much as possible.

1. Technical Design

When the microphone is placed in laminar flow, turbulence is generated, leading to unnecessary pressure changes on the diaphragm. By using the windshield, these pressure changes will be kept as far away from the diaphragm as possible.

In theory, this supports the idea of 'bigger is better design', but in reality it is a compromise between reduced air velocity, practical size, and self induced noise. Self perceived noise is the oscillation noise generated when the windshield begins to move around the microphone.

The size of GRAS windshield has been optimized. Its special open cell foam structure and the number of holes per inch (ppi) are designed to resist humid environment, while not significantly affecting the sound pressure measurement results.

If the windshield becomes wet, it is expected to experience frequency dependent attenuation. Therefore, the windshield cannot be used as a rain cover for the microphone.

2. Other alternative options

If longer outdoor listening time is required, it is recommended that users seek GRAS semi permanent nine and permanent nine outdoor microphone solutions:

GRAS 41AC-3 CCP Outdoor Community and Airport Noise Microphone

GRAS 41AC-4 LEMO community and airport noise outdoor microphone (0 V polarity)

If the reduction of turbulence is not sufficient to meet the user's measurement type, we recommend using intensity measurement techniques that can effectively suppress background noise. GRAS has a wide range of 2D, 3D, and broadband intensity probes, supporting CCP and LEMO input modules. Please refer to GRAS intensity probes.

If users need to measure sound pressure in a well-defined laminar airflow, such as in a wind tunnel, we recommend that they look for GRAS nose cones. Or look for our surface microphone, our new embedded microphone concept, or our turbulence screen.

Danish GRAS microphone grille and windshield ball

3、 Introduction to our company, Shanghai Xingtuo Machinery Equipment Co., Ltd.:

Our company is a legitimate agent and general distributor of ELTRA in Italy. Our company can provide professional ELTRA encoder technical support, and at the same time act as a cost-effective agent to sell most of Italy's ELTRA products, such as standard incremental encoders, absolute encoders, linear encoder systems, and encoder peripheral accessories Rich on-site and practical experience is the core competitiveness of our company. Providing customers with fast delivery time, competitive prices, and excellent technical services is our commitment and pursuit to all customers who use ELTRA products.

The main advantageous brands are:

1. Pneumatic brand

German brand: Festo, FESTO, Baode, GSR, Hilong, Mahler, Samson, SAMSON

Japanese brand: CKD, Hikari, Koganei, SMC, NOK, TACO

South Korea TKC YPC TPC UK Norgren NORGREN Italy UNIVER Italy Kangmaosheng USA Newman Tec USA SUN, Taiwan, China, Taiwan, China

(These pneumatic valves are mainly divided into many small types, such as throttle valves, pressure reducing valves, check valves, oil mist devices, filters, connectors, switches, air pipes, etc.) Wilkerson, USA

ASCO (main valve category, specific online search) Baode BURKERT mainly produces solenoid valves, flow switches, sensors, conductivity, transmitters, etc

2. Hydraulic brand:

NACHI from Japan, Nippon Steel, VICKERS from the United States, PARKER from the United States, HAWE from Germany, TOYOOKI from Japan, Daikin from Japan, ATOS Atos from Italy, REXROTH from Germany,

These are hydraulic products mainly used as reference, including solenoid valves, solenoid directional valves, proportional valves, relief valves, amplifiers, hydraulic pumps, gear pumps, plunger pumps, vane pumps, servo valves, etc

MOOG in the United States only produces servo valves

3. Industrial control products

Germany's Yifumen IFM, Germany's PIL Drunken Pilz, Japan's SUNX Vision, Germany's Turck TURCK, Japan's Keyence, Germany's Pf Plus, Germany's Phoenix, Germany's SICK, Italy's Jeffren GEFRAN, Germany's Siemens, Japan's Omron, Ansen, Germany's H&D, Germany's Baruff, Germany's Marler, Germany's NOVO.

Mainly engaged in sensors, relays, switches, safety barriers, and relays

Hessman in Germany mainly produces switches

4. Instrumentation category: Danish GRAS sound level meter. Swiss E+H, RoseMount under Emerson EMERSON in the United States, Swiss G+F: mainly produces transmitters, flow meters, pressure sensors, etc.