EP 3225038 B1 20180905 - LOW FREQUENCY ACTIVE ACOUSTIC ABSORBER BY ACOUSTIC VELOCITY CONTROL THROUGH POROUS RESISTIVE LAYERS
Title (en)
LOW FREQUENCY ACTIVE ACOUSTIC ABSORBER BY ACOUSTIC VELOCITY CONTROL THROUGH POROUS RESISTIVE LAYERS
Title (de)
NIEDERFREQUENTER AKTIVER SCHALLABSORBER DURCH AKUSTISCHE GESCHWINDIGKEITSSTEUERUNG DURCH PORÖSE RESISTIVE SCHICHTEN
Title (fr)
ABSORBEUR ACOUSTIQUE ACTIF BASSE FRÉQUENCE PAR COMMANDE DE LA VITESSE ACOUSTIQUE À TRAVERS DES COUCHES RÉSISTIVES POREUSES
Publication
Application
Priority
- GB 201421213 A 20141128
- IB 2015059029 W 20151123
Abstract (en)
[origin: GB2532796A] A device for wide band low frequency absorption comprises at least one electroacoustic transducer 1, mounted on an acoustic baffle 2, separating a closed rear volume 3 and a front volume 4. The front volume is closed by an acoustic fabric 5 of determined acoustic air-flow resistance. A power amplification electronic 6 with feedback control 7 is configured to obtain a transducer membrane velocity proportional to an input voltage, coming from a microphone 8 located in front of the acoustic fabric on a side opposite from the front volume. The microphone is connected to a preamplifier 9 and a feedforward control 10, with adjustable gain and band-pass filter, taking a first pressure signal coming from the microphone preamplifier and driving the power amplifier input. The feedforward control gain is equal to where Af is the fabric area, Als the projected transducer membrane area, R the fabric air-flow resistance and G1 the preamplifier gain, minimizing the acoustic pressure in the front volume, thus having a specific impedance, defined as pressure/velocity ratio, in front of the acoustic fabric equal to the determined air-flow resistance of the acoustic fabric.
IPC 8 full level
H04R 3/00 (2006.01); H04R 29/00 (2006.01)
CPC (source: EP GB US)
G10K 11/16 (2013.01 - GB); G10K 11/1781 (2017.12 - EP US); G10K 11/17857 (2017.12 - EP US); G10K 11/17861 (2017.12 - EP US); G10K 11/17881 (2017.12 - EP US); H04R 1/2869 (2013.01 - GB); H04R 3/002 (2013.01 - EP GB US); G10K 2210/12 (2013.01 - EP); G10K 2210/3026 (2013.01 - EP); G10K 2210/3027 (2013.01 - EP); G10K 2210/3212 (2013.01 - EP); H04R 29/001 (2013.01 - EP)
Designated contracting state (EPC)
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
DOCDB simple family (publication)
GB 201421213 D0 20150114; GB 2532796 A 20160601; EP 3225038 A1 20171004; EP 3225038 B1 20180905; WO 2016083971 A1 20160602
DOCDB simple family (application)
GB 201421213 A 20141128; EP 15810768 A 20151123; IB 2015059029 W 20151123