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ANC-Labo is a company specializing in Active Noise Control.

TEL. +81-78-747-2722

5-12-44,Hiyodori-dai,Kita-ku,KOBE,651-1123,JAPAN

Japanese

ANC siteANC Application

Duct noise

Construction site of hospital

Construction site of highway

Test bench for engines

Pile driving ship

Virtual point control

Tobacco-manufacturing plant


Duct noise

An application example for duct noises as a basic model.


ANC-Duo Duct_site

If any countermeasures have not been taken, the ventilation noise would go out into the neighboring high-rises. In such concrete fields, noises keep going without attenuation.


ANC-Duo Duct indside

This picture shows the inside of the duct. The two speakers output control sounds to cancel low-frequency noises from the duct fan. Because of random signal noises, feedforward control is applied.


Construction site of hospital

The photo shows Okayama university Hospital. It is an ANC application to the construction site.
(Being constructed by Shimizu corporation)


ANC-Duo okayama_site

The construction of an additional word is going on in the hospital premises, even though there are many hospitalized patients. So low-frequency noises must be treated.


ANC-Duo okayama_7090

Feedback control is used because the noise from the crane engine is periodic.


Hospital construction site

Video clip of the ANC result
The result shows the 100Hz periodic sound is suppressed by 20dB.

Caution) The relevant sound is 100Hz. Use a woofer speaker to play. Normal PC speakers or headphones can not reproduce the sound.

ANC result


Construction site of highway

ANC is used to suppress exhaust gas noises from the machinery engines at a highway construction site.


ANC-Duo shinmeishin_site_1

This site is vast and open, but Low-frequency noises reach to the end of the site. The construction crews use ANC systems with consideration for the neighboring residents.


ANC-Duo shinmeishin_site_2

Feedback control is applied

ANC result


ANC-Duo shinmeishin_site_3

ANC system is installed on the backhoe too.


Test bench for engines

ANC system is installed to cover silencers at diesel engine manufacturing plants.


ANC-Duo diesel_test_bench_1

The exhaust pipe for engines test bench has a silencer, but low-frequency sounds below 100Hz can not be attenuated. So ANC system is used with consideration for the neighboring residents.


ANC-Duo diesel_test_bench_2

The control speakers are moved closer to increase the ANC effect in case of a bigger power engine.


ANC-Duo diesel_test_bench_3

Tested engines got even more powerful. so more powerful speakers have been installed.
The work was done in the blazing sun. (*_*);

ANC result


Pile driving ship

ANC examples for several diesel engines on a pile driving ship.


ANC-Duo crane_ship_1

ANC is applied for an exhaust gas outlet from the generator engine. The engine has a silencer, which can not suppress very low frequency noises under 100Hz.


ANC-Duo crane_ship_2

Low-frequency sounds carry far on the sea and reach the shore.
The crew use ANC with consideration for residents around the bank protection work site.


ANC-Duo crane_ship_3

The crew install the control speakers at the exhaust gas outlet of the hydraulic pump for the pile driver.
The continuous engine low-frequency sound is more annoying than the pile hammering sounds.
(Photo of hydraulic pump from the above.)


ANC-Duo crane_ship_4

This treatment of this ship is a perfect case.
The sound insulating boards are for high-frequency noises.
And for low-frequency noises....


ANC-Duo crane_ship_5

Of cause, Active noise control system is involved. Those are the basics for noise control.
(Photo of ANC speakers inside the sound insulating boards from the above.)

(Penta-ocean construction style)


Virtual point control

The sound field near control speakers is linearly turbulent. In this method, it controls the near-field as if it controls far-field. (Kajima corporation style)


ANC-Duo anc virtual mic

Sorry for no photos.
(Photos of sites using the virtual point control method are not allowed to be posted.)
Technical brief


Tobacco-manufacturing plant

ANC system used at the area requiring ear-plugs in a Tobacco-manufacturing plant


ANC-Duo tabacco_plant_1

To protect the workers in front of the machine from damaging their ears.

They take good measures to contain noises inside, but some noises leak from apertures which are needed to operate lines.
The worker damage their health by low-frequency noises without putting ear-plugs.


ANC-Duo tabacco_plant_2

ANC system suppresses harmonic sounds (60Hz fundamental) from the gears in the product line.



The sound repeats ANC ON/OFF every 10 sec.
(Play back via a woofer speaker.)


バナースペース

ANC-Labo Co.,LTD.

5-12-44, Hiyodori-dai, Kita-ku
KOBE, 651-1123, JAPAN

TEL +81-78-747-2722 (S.Awata)
FAX +81-78-747-2723