A waveform correction processor corrects the waveform of a first digital audio signal (a CD signal, for example) having a first sampling frequency. A bit depth and sampling frequency converter converts the first digital audio signal with the waveform corrected by the first waveform correction processor to a second digital audio signal (a high-resolution digital audio signal, for example) having a second sampling frequency, which is higher than the first sampling frequency. The waveform correction processor corrects the waveform of the second digital audio signal.

A waveform correction processor corrects the waveform of a first digital audio signal (a CD signal, for example) having a first sampling frequency. A bit depth and sampling frequency converter converts the first digital audio signal with the waveform corrected by the first waveform correction processor to a second digital audio signal (a high-resolution digital audio signal, for example) having a second sampling frequency, which is higher than the first sampling frequency. The waveform correction processor corrects the waveform of the second digital audio signal.

A system capable of self-adjusting both sound level and spectral content to improve audibility and intelligibility of electronic device audible cues. Audible cues are stored as sound files. Ambient noise is detected, and the output of the audible cues is altered based on the ambient noise. Various embodiments include processed sound files that are more robust in noisy environments.

A local extremum calculator detects a local maximum sample and a local minimum sample of a digital audio signal. A number-of-sample detector detects a sample interval between the local maximum sample and the local minimum sample. A difference value calculator calculates difference values between adjacent samples. A correction value calculator calculates a first correction value by multiplying the difference value between the local maximum sample and a first adjacent sample by a coefficient and calculates a second correction value by multiplying the difference value between the local minimum sample and a second adjacent sample by the coefficient. When a periodic signal detector detects that the digital audio signal is a single sine wave, an adder/subtractor does not add the first correction value to the first adjacent sample, and does not subtract the second correction value from the second adjacent sample.

A local extremum calculator detects a local maximum sample and a local minimum sample of a digital audio signal. A number-of-sample detector detects a sample interval between the local maximum sample and the local minimum sample. A difference value calculator calculates difference values between adjacent samples. A correction value calculator calculates a first correction value by multiplying the difference value between the local maximum sample and a first adjacent sample by a coefficient and calculates a second correction value by multiplying the difference value between the local minimum sample and a second adjacent sample by the coefficient. When a periodic signal detector detects that the digital audio signal is a single sine wave, an adder/subtractor does not add the first correction value to the first adjacent sample, and does not subtract the second correction value from the second adjacent sample.

An even-numbered harmonic adder adds a correction value to a first adjacent sample that is the next sample after a first local minimum sample, and subtracts a correction value from a second adjacent sample that is one sample before a local maximum sample. The even-numbered harmonic adder adds a correction value to a third adjacent sample that is the next sample after the local maximum sample, and subtracts a correction value from a fourth adjacent sample that is one sample before a second local minimum sample. An odd-numbered harmonic adder subtracts a correction value from the first local minimum sample and the second local minimum sample, and adds a correction value to the local maximum sample.

An even-numbered harmonic adder adds a correction value to a first adjacent sample that is the next sample after a first local minimum sample, and subtracts a correction value from a second adjacent sample that is one sample before a local maximum sample. The even-numbered harmonic adder adds a correction value to a third adjacent sample that is the next sample after the local maximum sample, and subtracts a correction value from a fourth adjacent sample that is one sample before a second local minimum sample. An odd-numbered harmonic adder subtracts a correction value from the first local minimum sample and the second local minimum sample, and adds a correction value to the local maximum sample.

An exemplary system includes a processor communicatively coupled to a memory and configured to execute instructions to generate a modified audiogram for a user of a hearing device. The modified audiogram may be based on a frequency lowering scheme that maps at least some audio frequencies included in a first set of audio frequencies to relatively lower audio frequencies to form a second set of audio frequencies. The modified audiogram may indicate a set of modified hearing thresholds of the user at the first set of audio frequencies. The generating of the modified audiogram may include applying an inverse of the frequency lowering scheme to the set of modified hearing thresholds at the second set of audio frequencies to obtain the set of modified hearing thresholds of the modified audiogram at the first set of audio frequencies.

An exemplary system includes a processor communicatively coupled to a memory and configured to execute instructions to generate a modified audiogram for a user of a hearing device. The modified audiogram may be based on a frequency lowering scheme that maps at least some audio frequencies included in a first set of audio frequencies to relatively lower audio frequencies to form a second set of audio frequencies. The modified audiogram may indicate a set of modified hearing thresholds of the user at the first set of audio frequencies. The generating of the modified audiogram may include applying an inverse of the frequency lowering scheme to the set of modified hearing thresholds at the second set of audio frequencies to obtain the set of modified hearing thresholds of the modified audiogram at the first set of audio frequencies.

A mixing apparatus having a stereo output includes: a first signal processor that mixes a first signal and a second signal in a first channel; a second signal processor that mixes a third signal and a fourth signal in a second channel; a third channel that processes a weighted sum of a signal of the first channel and a signal of the second channel; and a gain deriving part that generates a gain mask commonly used in the first channel and the second channel, wherein the gain deriving part determines a first gain commonly applied to the first signal and the third signal, and a second gain commonly applied to the second signal and the fourth signal, so that predetermined conditions for simultaneous gain generation are satisfied at least at the first channel and the second channel among the first channel, the second channel, and the third channel.