# US 2020/0396554 A1 · System and a method for detecting loudspeaker chain failure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0396554 A1 - Document ID: US20200396554A1 - Status: Published application - Kind: A1 - Application number: 16/899,364 - Filed: 2020-06-11 - Published: 2020-12-17 - Earliest claimed: 2019-06-13 - Assignees: SystèMes De ContrôLe Actif Soft Db Inc. - Applicants: Soft Db Inc. - Inventors: DAVID CASTONGUAY; ALEX BOUDREAU - Web page: https://patentgrep.com/patent/US20200396554A1 ## CPC - H03F 3/68: Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics {(power amplifiers using a combination of several semiconductor amplifiers H03F3/211; combinations of amplifiers using coupling networks with distributed constants H03F3/602)} - H04R 29/001: {for loudspeakers (H04R29/007 takes precedence)} - H03F 3/183: with semiconductor devices only - H03F 3/187: in integrated circuits - H03F 3/72: Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal - H04R 29/007: {for public address systems (public address systems per se H04R27/00)} - H03F 2200/03: the amplifier being designed for audio applications - H03F 2200/321: Use of a microprocessor in an amplifier circuit or its control circuit - H03F 2200/462: the current being sensed - H03F: AMPLIFIERS - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) ## Abstract A method and a system for monitoring operation of at least one loudspeaker in a system comprising a plurality of loudspeakers connected in series on a same amplifier output in at least one loudspeaker chain driven by an amplifier board, the method comprising measuring a current consumed by the amplifier in an operating position of the plurality of loudspeakers, yielding a reference current; stopping the masking system into an idle position; emitting the reference signal, measuring an idle current consumed by the amplifier; and comparing the idle current with the reference current. The system comprises a microprocessor unit and a current measurement module, wherein the current measurement module is configured to measure a current drawn by the amplifiers and feed a resulting signal to the microprocessor unit; and the microprocessor unit generates an output signal to respective output channel. ## Claims ### Claim 1 A controller/amplifier board for loudspeaker chains, comprising: a number of output channels to as many loudspeaker chains; an amplifier for each one of the output channels; a microprocessor unit; and a current measurement module; wherein said current measurement module is configured to measure a current drawn by the amplifiers and feed a resulting signal to said microprocessor unit; and said microprocessor unit generates an output signal to the respective output channel. ### Claim 2 (depends on 1) The controller/amplifier board of claim 1, wherein said current measurement module comprises a current sensor inserted on a main DC amplifier supply line; the microprocessor unit receiving a signal from the current sense amplifier and generating the output signal to the respective output channel. ### Claim 3 (depends on 1) The controller/amplifier board of claim 1, wherein said current measurement module comprises a current sense amplifier and said current sense amplifier amplifies a voltage drop across the current sensor with a fixed gain. ### Claim 4 A method for monitoring a loudspeaker chains system, comprising: measuring a reference idle current Iidle in an idle position of the system; generating an output signal Voutput to each loudspeaker chain of the system and measuring a current Im on each loudspeaker chain; subtracting the reference idle current Iidle to the current Im measured at each loudspeaker chain to determine a current drawn by each loudspeaker chain and obtaining a measured impedance of each loudspeaker chain; and comparing of the measured impedance of each loudspeaker chain with a reference impedance value of each loudspeaker chain. ### Claim 5 (depends on 4) The method of claim 4, comprising determining the impedance of the loudspeaker chains from a supply voltage of the system (Vsupply), the output signal Voutput, the current Im measured at each loudspeaker chain, the reference idle current Iidle and an efficiency of the loudspeaker chains of the system. ### Claim 6 (depends on 4) The method of claim 4, comprising selecting a low frequency output signal Voutput in combination with an impedance range. ### Claim 7 (depends on 4) The method of claim 4, wherein said determining the impedance of the loudspeaker chains of the system comprises using the following relation: Impedance=Voutput/Ioutput with Ioutput=(Vsupply/Voutput)*(Im-Iidle)*Ampeff; where Vsupply is the DC supply voltage of the amplifier; and Ampeff is the efficiency of amplifiers of the loudspeaker chains. ### Claim 8 (depends on 4) The method of claim 4, wherein the reference impedance value of each loudspeaker chain is specified by manufacturers. ### Claim 9 (depends on 4) The method of claim 4, comprising, after said measuring the current Im on each loudspeaker chain; setting the system in an operating position and measuring a current of each loudspeaker chain, yielding an operation current for each loudspeaker chain, and comparing the operation current to the reference idle current Iidle. ### Claim 10 (depends on 4) The method of claim 4, wherein said generating the output signal Voutput comprises generating a low frequency sinusoidal signal Voutput to each output channel successively. ### Claim 11 (depends on 4) The method of claim 4, wherein said generating the output signal Voutput comprises selecting a low frequency and generating a low frequency sinusoidal signal Voutput to each output channel successively. ### Claim 12 (depends on 4) The method of claim 4, wherein said generating the output signal Voutput comprises selecting a low frequency maximizing the measured current consumption of the amplifiers. ### Claim 13 A method for monitoring operation of at least one loudspeaker in a system comprising a plurality of loudspeakers connected in series on a same amplifier output in at least one loudspeaker chain driven by an amplifier board, comprising measuring a current consumed by the amplifier in an operating position of the plurality of loudspeakers, yielding a reference current; stopping the masking system into an idle position; emitting the reference signal, measuring an idle current consumed by the amplifier; and comparing the idle current with the reference current. ### Claim 14 (depends on 13) The method of claim 13, comprising measuring the idle current consumption of the amplifier, selecting a stimulation low frequency; stimulating the loudspeaker chain at the selected stimulation low-frequency; measuring an operating current consumption of the amplifier; and comparing the operating current consumption with the idle current consumption. ### Claim 15 (depends on 13) The method of claim 13, comprising measuring the idle current consumption of the amplifier, selecting a stimulation low frequency; stimulating the loudspeaker chain at the selected stimulation low-frequency; measuring an operating current consumption of the amplifier; and comparing the operating current consumption with the idle current consumption, wherein said selecting a stimulation low frequency comprises selecting a low frequency maximizing the measured operating current consumption of the amplifier. ### Claim 16 (depends on 13) The method of claim 13, comprising measuring the idle current consumption of the amplifier, selecting a stimulation low frequency; stimulating the loudspeaker chain at the selected stimulation low-frequency; measuring an operating current consumption of the amplifier; and comparing the operating current consumption with the idle current consumption, the method comprising stimulations on the loudspeaker chain at a frequency range between about 20 Hz and about 100 Hz. ### Claim 17 (depends on 13) The method of claim 13, comprising measuring the idle current consumption of the amplifier, selecting a stimulation low frequency; stimulating the loudspeaker chain at the selected stimulation low-frequency; measuring an operating current consumption of the amplifier; and comparing the operating current consumption with the idle current consumption, the method comprising stimulations on the loudspeaker chain at a frequency range between about 20 Hz and about 60 Hz. ### Claim 18 (depends on 13) The method of claim 13, comprising measuring the idle current consumption of the amplifier, selecting a stimulation low frequency; stimulating the loudspeaker chain at the selected stimulation low-frequency; measuring an operating current consumption of the amplifier; and comparing the operating current consumption with the idle current consumption, the method comprising stimulations on the loudspeaker chain in a frequency range between about 40 Hz and about 60 Hz. ### Claim 19 (depends on 13) The method of claim 13, comprising measuring the idle current consumption of the amplifier, selecting a stimulation low frequency; stimulating the loudspeaker chain at the selected stimulation low-frequency; measuring an operating current consumption of the amplifier; and comparing the operating current consumption with the idle current consumption, wherein said selecting a stimulation signal comprises selecting a frequency maximizing high current and a low acoustical emission and an amplitude maximizing current. ### Claim 20 A method for monitoring disconnection of at least one loudspeaker in a sound masking system or a public address system comprising a plurality of loudspeakers connected in series on a same amplifier output, comprising measuring a current consumed by the amplifier in an operating position of the plurality of loudspeakers, yielding a reference current; stopping the masking system into an idle position; emitting the reference signal, measuring an idle current consumed by the amplifier; and comparing the idle current with the reference current.