Abstract: The invention relates to a sound reinforcement system (400) comprising a loudspeaker (130) and two audio amplifiers (410, 410?), wherein: each audio amplifier (410, 410?) is equipped with an output relay (214), which extends to an amplifier output terminal (116) of the associated audio amplifier, as well as a ground output terminal (118); each of two terminals of the loudspeaker (130) is connected to one of the amplifier output terminals; the ground output terminals (118) of the two audio amplifiers (410, 410?) are connected to one another and/or to ground. The invention also relates to a method for operating a sound reinforcement system (400) of said type.

Abstract: In the field of audio amplifiers, the prior art for high output power levels is now to use class D technology. In this technology, audio signals are converted into a pulsed signal. An audio amplifier 1 is proposed, with a modulator section 4 for accepting an input signal and outputting two intermediate signals, wherein the modulator section 4 is designed to generate the intermediate signals by modulating the input signal, with an amplifier section 8 for accepting the two intermediate signals and outputting two amplified signals, wherein the amplifier section 8 is designed to generate the two amplified signals by amplifying the two intermediate signals, the amplifier section having two power stages 11;12, with an end section 21 for accepting the two amplified signals and for outputting an output signal for a loudspeaker device 2, wherein the audio amplifier 1 can be switched between parallel operation and bridge operation.

Abstract: In the field of audio amplifiers, the prior art for high output power levels is now to use class D technology. In this technology, audio signals are converted into a pulsed signal. An audio amplifier 1 is proposed, with a modulator section 4 for accepting an input signal and outputting two intermediate signals, wherein the modulator section 4 is designed to generate the intermediate signals by modulating the input signal, with an amplifier section 8 for accepting the two intermediate signals and outputting two amplified signals, wherein the amplifier section 8 is designed to generate the two amplified signals by amplifying the two intermediate signals, the amplifier section having two power stages 11;12, with an end section 21 for accepting the two amplified signals and for outputting an output signal for a loudspeaker device 2, wherein the audio amplifier 1 can be switched between parallel operation and bridge operation.

Abstract: The invention relates to a method for protecting a component (6) within an audio device (4) from the exceedance of a maximum internal temperature (TI), wherein a power loss (V) of the component (6) is determined, a measurement temperature (TM) is measured on the component (6), a temperature difference (DT) for the component (6) between the measurement temperature (TM) on the component and the internal temperature (TI) is determined from the power loss (V) by means of a thermal model (14) of the component (6), the internal temperature (TI) is determined as the sum of the measurement temperature (TM) and the temperature difference (DT), a permissible maximum value (VM) for the power loss (V) is determined on the basis of the internal temperature (TM) and known component data (16) of the component (6), and the component (6) is operated in a normal operating mode (N) if the power loss (V) does not exceed the maximum value (VM) or the component (6) is otherwise operated in reduced-power economy operating mode (S)

Abstract: The invention relates to a method for operating a class-D amplifier (2) for an audio signal (4), which class-D amplifier contains an output stage (10) and a signal-processing unit (12) in a signal path (6), wherein a voltage (U) of at least two magnitudes (U1, U2) is provided for the output stage (10), a voltage requirement (B) of the output stage (10) for the audio signal (4) is predictively determined from the audio signal (4) at a measurement location (14) before the signal-processing unit (12), a magnitude (U1, U2) that is minimally sufficient for the voltage requirement (B) is selected on the basis of the voltage requirement (B) and said magnitude is applied to the output stage (10) before the amplification.

Abstract: The invention relates to a method for operating a class-D amplifier (2) for an audio signal (4), which class-D amplifier contains an output stage (10) and a signal-processing unit (12) in a signal path (6), wherein a voltage (U) of at least two magnitudes (U1, U2) is provided for the output stage (10), a voltage requirement (B) of the output stage (10) for the audio signal (4) is predictively determined from the audio signal (4) at a measurement location (14) before the signal-processing unit (12), a magnitude (U1, U2) that is minimally sufficient for the voltage requirement (B) is selected on the basis of the voltage requirement (B) and said magnitude is applied to the output stage (10) before the amplification.

Abstract: The invention relates to a method for protecting a component (6) within an audio device (4) from the exceedance of a maximum internal temperature (TI), wherein a power loss (V) of the component (6) is determined, a measurement temperature (TM) is measured on the component (6), a temperature difference (DT) for the component (6) between the measurement temperature (TM) on the component and the internal temperature (TI) is determined from the power loss (V) by means of a thermal model (14) of the component (6), the internal temperature (TI) is determined as the sum of the measurement temperature (TM) and the temperature difference (DT), a permissible maximum value (VM) for the power loss (V) is determined on the basis of the internal temperature (TM) and known component data (16) of the component (6), and the component (6) is operated in a normal operating mode (N) if the power loss (V) does not exceed the maximum value (VM) or the component (6) is otherwise operated in reduced-power economy operating mode (S)

Abstract: The invention relates to an audio amplifier (1) for amplifying an input signal into an output signal, comprising an output amplification stage (6), wherein the output amplification stage (6) for the amplification of an intermediate signal into the output signal is designed as an amplifier operating in switching operation, and further comprising a limiter device (4), which from a programming and/or a circuit design point of view is designed to generate the intermediate signal on the basis of the input signal, wherein the level of the intermediate signal is always limited by a maximum load as a function of a settable maximum output and a load impedance which is coupled and/or can be coupled the audio amplifier or equivalent parameter thresholds such that the output signal does not exceed the maximum load at the load impedance, or the equivalent parameter thresholds, independently of the input signal.

Abstract: The invention relates to a cover (2) for a portable electronic mixer amplifier (1), said cover (2) comprising at least: a cover shell (4) having a front side (4.1) and a rear side for being mounted on a lower device part (3) of the mixer amplifier (1), closure devices (8) for locking the cover (2) to the lower device part (3), wherein the closure devices (8) can be adjusted between an open and a locked position. According to the invention, the cover (2) comprises a carrying device (6) which allows a user to carry the device, and closure recesses (10) are designed in the cover shell (4) in which the closure devices (8) are accommodated. The closure recesses, in particular actuatable closure parts (20), are preferably aligned in the locked position with the front side (4.1) of the cover shell and protrude when in the open position.

Abstract: The invention relates to an optical waveguide system (20) for a display device (1) and to such a display device (1), wherein the optical waveguide system (20) comprises at least one optical waveguide group (20-1, 20-2, 20-3, 20-4, 20-5, 20-6), wherein at least one of the optical waveguide groups (20-1, 20-2, 20-3, 20-4, 20-5) comprises: several optical waveguides (18) made of a material that is transparent to the light of a LED (14), spacers (34) for adjusting a distance of an interspace (30) between a circuit carrier (12) and a front panel (2), and a housing (22) which is made of a material that is intransparent to the light, surrounds each of the several optical waveguides (18) and connects the optical waveguides (18) and the spacers (34) among each other and to each other.

Abstract: The invention relates to a cover (2) for a portable electronic mixer amplifier (1), said cover (2) comprising at least: a cover shell (4) having a front side (4.1) and a rear side for being mounted on a lower device part (3) of the mixer amplifier (1), closure devices (8) for locking the cover (2) to the lower device part (3), wherein the closure devices (8) can be adjusted between an open and a locked position. According to the invention, the cover (2) comprises a carrying device (6) which allows a user to carry the device, and closure recesses (10) are designed in the cover shell (4) in which the closure devices (8) are accommodated. The closure recesses, in particular actuatable closure parts (20), are preferably aligned in the locked position with the front side (4.1) of the cover shell and protrude when in the open position.

Abstract: The invention relates to an optical waveguide system (20) for a display device (1) and to such a display device (1), wherein the optical waveguide system (20) comprises at least one optical waveguide group (20-1, 20-2, 20-3, 20-4, 20-5, 20-6), wherein at least one of the optical waveguide groups (20-1, 20-2, 20-3, 20-4, 20-5) comprises: several optical waveguides (18) made of a material that is transparent to the light of a LED (14), spacers (34) for adjusting a distance of an interspace (30) between a circuit carrier (12) and a front panel (2), and a housing (22) which is made of a material that is intransparent to the light, surrounds each of the several optical waveguides (18) and connects the optical waveguides (18) and the spacers (34) among each other and to each other.