A DJ media player is provided. The DJ media player includes a display to show audio playback information; a platter used to control audio playback; one or more energy-storing devices; and a processor for responding to DJ media-player electrical-power loss. Responding to DJ media-player electrical-power loss includes storing electrical charge on energy-storing devices; sensing a disruption in electrical current supplied by a power source to the DJ media player; powering the DJ media player using the electrical charge on the energy-storing devices; and displaying a notification on a DJ media-player display that there was a disruption of power. Responding to electrical-power loss comprises performing a safe shutdown procedure for avoiding file and system corruption.

Systems and methods for selecting an audio track by performing a gesture on a track-list image are provided. The system includes a processor that performs a method including displaying the audio-track list, detecting a contact with the touchscreen display at a location corresponding to the audio track, detecting a continuous movement of the contact in a direction, detecting a length of the continuous movement, and selecting the audio track if the continuous movement has a length longer than a threshold length. The method includes shifting text associated with the audio track based on the length and direction of the continuous movement. The method includes determining that the selection is a command to queue the audio track for playback or add it to a preparation track list. This determination may be based on the direction of the continuous movement.

Systems and methods for musical tempo detection are provided. The method includes detecting peaks and their locations in a waveform of a digital audio track, and dividing the track into first measures with a first-measure length based on a first estimated tempo. The method includes determining distances between a beginning of the first measures and each peak location, and determining a first number of peaks having the same distance from the beginning of the first measures. The method includes dividing the track into second measures with a second-measure length based on a second estimated tempo; determining distances between a beginning of the second measures and each peak location; and determining a second number of peaks having the same distance from the beginning of each of the second measures. The method includes estimating an accurate tempo by comparing the first number of peaks and the second number of peaks.

Systems and methods for generating a graphical representation of audio-file playback during playback manipulation are provided. The system may include a processor that performs a method including displaying a waveform during audio-file playback by scrolling the waveform from a right to a left portion of a display. The method includes receiving a command to manipulate the audio-file playback and displaying a first half of the waveform corresponding to the manipulated audio-file playback until a command is received to resume the audio-file playback. The first half of the waveform is a portion of the waveform adjacent to a horizontal or vertical axis. The method includes simultaneously displaying a second half of the waveform and displaying the first half of the waveform corresponding to the manipulated audio-file playback. The second half of the waveform is on an opposite side of the axis from the first half of the waveform.

Systems and methods for generating a graphical representation of audio signal data during time compression or expansion are provided. The system may include a processor that performs a method including displaying a waveform during audio-signal playback at a first speed by scrolling the waveform from aright portion of a display to a left portion of the display. The method includes receiving a command to increase or decrease the audio-signal playback speed and horizontally expanding or horizontally contracting the waveform in response to receiving the command to increase or decrease the audio-signal playback speed.

A hand-held strumming device includes a hollow body, a power source, a motor, a regulator, and a strummer. The power source is disposed in the hollow body. The motor is in electrical communication with the power source. The regulator is in electrical communication with both the motor and the power source. The regulator is configured to selectively adjust a rotational speed of the motor. The strummer is rotatably disposed on the disk. The strummer is configured to be presented to strings of a stringed instrument upon rotation of the motor to strum the strings.

A method and apparatus for presenting at least a portion of a musical notation of a starting point of a song to a user, including a first note or chord to be played; indicating a tempo of the song to the user; receiving from a musical instrument played a signal indicating how the musical instrument is being played; monitoring triggers and responsively to detecting a starting trigger beginning to playback one or more backing tracks; detecting the starting trigger by determining that the user has provided a starting sign independent of the apparatus; and synchronizing the playback of the one or more backing tracks using a time when the user has provided the starting sign.

Systems and methods for musical tempo detection are provided. The method includes detecting peaks and their locations in a waveform of a digital audio track, and dividing the track into first measures with a first-measure length based on a first estimated tempo. The method includes determining distances between a beginning of the first measures and each peak location, and determining a first number of peaks having the same distance from the beginning of the first measures. The method includes dividing the track into second measures with a second-measure length based on a second estimated tempo; determining distances between a beginning of the second measures and each peak location; and determining a second number of peaks having the same distance from the beginning of each of the second measures. The method includes estimating an accurate tempo by comparing the first number of peaks and the second number of peaks.

Systems and methods for providing audio-file loop-playback functionality are provided. The system includes a processor that performs a method including setting a playback loop start-point based on a first selection of a button; setting a loop end-point, associating a loop with an audio file, and entering into the loop based on a second selection of the button; and exiting the loop based on a third selection of the button. Associating the loop with the audio file includes adding metadata to the audio file. The metadata associates the loop with a button. The method includes reentering the loop based on a fourth selection of the button and exiting the loop based on a fifth selection of the button.

A DJ media player is provided. The DJ media player includes a display to show audio playback information, a patter used to control audio playback, a light emitting element for displaying different colors, and an interface located on the media player for selecting different colors for the light emitting element. The interface is a graphical user interface on the display. The display is a touchscreen display and one or more colors are selected by making contact with the touchscreen display. The light emitting element is in a platter housing.