Embodiments relate generally to hearing protection devices which incorporate a calibration mode which allows the user to perform a calibration test to determine an individualized hearing threshold. Embodiments of the device may also comprise a normal mode to prevent input signals greater than the individualized hearing threshold from being transmitted to the user's ear canal. In addition, embodiments may comprise a normal mode configured to limit input signals to less than or equal to a standard industry threshold in the case no calibration test has been completed by the user. This may increase user comfort and prevent hearing damage.

Embodiments relate generally to hearing protection devices which incorporate a calibration mode which allows the user to perform a calibration test to determine an individualized hearing threshold. Embodiments of the device may also comprise a normal mode to prevent input signals greater than the individualized hearing threshold from being transmitted to the user's ear canal. In addition, embodiments may comprise a normal mode configured to limit input signals to less than or equal to a standard industry threshold in the case no calibration test has been completed by the user. This may increase user comfort and prevent hearing damage.

A portable speaker system for an electric string instrument such as a guitar. The portable speaker system has a housing including an audio jack for receiving a raw audio signal from a guitar, an amplifier, a speaker, and a power supply. The portable speaker system attaches to the guitar by a button connector which releasably attaches to a strap button of the guitar, and a stabilizer for inhibiting rotation of the portable speaker system when attached to the guitar. The portable speaker system portably generates output sound from the raw audio signal. The portable speaker system can couple with a portable computing device, which can process the raw audio signal and provide a supplementary audio signal, from which the portable speaker system can portably generate output sound.

A portable speaker system for an electric string instrument such as a guitar. The portable speaker system has a housing including an audio jack for receiving a raw audio signal from a guitar, an amplifier, a speaker, and a power supply. The portable speaker system attaches to the guitar by a button connector which releasably attaches to a strap button of the guitar, and a stabilizer for inhibiting rotation of the portable speaker system when attached to the guitar. The portable speaker system portably generates output sound from the raw audio signal. The portable speaker system can couple with a portable computing device, which can process the raw audio signal and provide a supplementary audio signal, from which the portable speaker system can portably generate output sound.

A device includes a sensor signal input node and a high-pass filter stage. The high-pass filter stage includes an operational amplifier and a feedback integrator. The operational amplifier includes an input node coupled to the sensor signal input node. The feedback integrator is coupled between an output node of the operational amplifier and the input node of the operational amplifier to set a high-pass pole frequency of the high-pass filter stage.

Example embodiments provide a process that includes one or more of receiving an audio signal at a feedback compressor circuit, determining how much to attenuate the audio signal when a power level of the audio signal exceeds a threshold power level, combining the audio signal with an auxiliary attenuation signal from an auxiliary attenuation source and a compressed attenuation signal from the feedback compressor circuit to create a combination signal, and generating an audio output signal of the feedback compressor circuit based on the combination signal.

A combined ambient sound and secondary audio system comprises at least one microphone for receiving ambient sound, at least one receiver for receiving secondary audio from a secondary audio source not audible in the ambient sound. The system further includes a memory storing one or more sets processing parameters comprising instructions for processing the ambient sound and the secondary audio and a processor coupled to the memory, the microphone, and the receiver configured to generate combined ambient and secondary sound by combining the ambient sound and the secondary audio as directed by a selected set of processing parameters retrieved from the memory.

A combined ambient sound and secondary audio system comprises at least one microphone for receiving ambient sound, at least one receiver for receiving secondary audio from a secondary audio source not audible in the ambient sound. The system further includes a memory storing one or more sets processing parameters comprising instructions for processing the ambient sound and the secondary audio and a processor coupled to the memory, the microphone, and the receiver configured to generate combined ambient and secondary sound by combining the ambient sound and the secondary audio as directed by a selected set of processing parameters retrieved from the memory.

Various implementations include a common mode voltage controller for a self-boosting push pull amplifier. In some implementations, input signal are processed by: calculating, based upon the input signal, a maximum duty cycle to achieve a target differential in an output of the self-boosting push pull amplifier; calculating, based on the input signal, a set of control parameters associated with adjusting a common mode voltage of the output; and generating, based on the input signal, a pair of signals configured to adjust the common mode voltage of the output, wherein the pair of signals include a gain adjustment and offset based on the maximum duty cycle and the set of control parameters, and wherein the pair of signals are configured to maintain the target differential in the output of the self-boosting push pull amplifier as the common mode voltage is adjusted to a different operating point.

application relates to an amplifier selectively operable in first or second modes. The first mode is a BTL mode with first and second output drivers (103p, 103n) both active to generate respective driving signals that vary with an input signal. The second mode is an SE mode, where the first output driver (103p) is active to generate a driving signal at and the output of the second driver (103n) is held constant. A controller (201) selectively controls the mode based on an indication of output signal amplitude. In the first mode, a ratio of magnitude of the two driving signals varies with the indication of output signal amplitude, i.e. the magnitudes of the two driving signals may vary so as to be not equal.