An impedance conversion device includes: a first input terminal to which a first analog signal output from an electric musical instrument is input; a splitter configured to split the first analog signal into a second analog signal and a third analog signal; a first output terminal from which the second analog signal is output; an impedance conversion circuit configured to convert an impedance of the third analog signal; and a second output terminal from which an analog signal obtained by converting the impedance is output. An input impedance of the impedance conversion circuit is approximately 1 G or more.

An input musical sound signal is input to band pass filters, and pass musical sound signals for each sound pitch are acquired. Total level ratios based on a total of levels of a sound pitch lower than those of the pass musical sound signals are calculated from the levels that are levels of the pass musical sound signals, and output coefficients are acquired on the basis of the total level ratios. Levels of octave musical sound signals acquired by converting the pass musical sound signals into sound pitches lower than those of the pass musical sound signals by one octave are multiplied by the output coefficients. In accordance with this, the octave musical sound signals of a low sound pitch can be extracted from among the octave musical sound signals.

A device includes a sensor circuit configured for installation in a stringed instrument such that the sensor circuit is electrically distinct from a pickup circuit of the stringed instrument, the pickup circuit including a pickup disposed proximate a string of the stringed instrument and configured to produce an audio signal of the stringed instrument in response to a movement of the string, and the string, the sensor circuit including a capacitive sensor and a sensor processing circuit in electronic communication with the capacitive sensor configured to produce a data signal based on a state of the capacitive sensor.

A musical instrument pickup, in particular for a plucked string instrument and/or a bowed string instrument. The pickup comprises at least one sensor which is designed to convert soundwaves detected by the sensor into electric signals. The pickup has a digital audio bus interface which is designed to transmit electric signals and supply an electric current to at least parts of the musical instrument pickup via a connection cable which can be releasably connected or captively connected to the digital audio bus interface and which only has two wires or at least two wires. The musical instrument pickup system can be equipped with the musical instrument pickup and can be used as an automotive audio bus for or as an audio bus interface of the pickup.