Impedance is the resistance of the headset itself, in ohms. The smaller the impedance, the easier it is to drive the earphone, and the larger the impedance, the harder it is to drive. The general walkman earphone impedance is 16Ω-64Ω. Typically, headphone impedance is larger at low frequencies, so low frequencies are less attenuated than high frequencies;noise cancelling earbuds and earphones， for most numbers, increasing the output impedance will make the sound darker and more mixed (the power amplifier will also have less control over the headphone's driver unit) ). But some headphones require high impedance to hear better. The sound of headphones with too much resistance will sound a bit mixed, and for various portable players, such as CD, MD or Mp3, low-impedance headphones (usually below 50 ohms) are generally used. Impedance headphones are easier to drive, and at the same time, pay attention to the high sensitivity. For Walkman, Mp3, Mp4, and CD, the sensitivity index is more important. Of course, headphones with higher impedance will sound better when paired with a sound source with high output power.
The size of the headphone impedance is also closely related to the sound quality of the headphone. The impedance changes with the frequency. The impedance of the headphone is larger at low frequencies and smaller at high frequencies. Therefore, for most headphones, increasing the system impedance will cause The voice became even more dim.
Basic Concepts of Impedance
When describing impedance, several terms should be understood.
When viewed as a simple electronic circuit, the impedance of the audio source can be written as the output (or source) impedance, while the impedance of the headphone can be viewed as the load impedance.
Headphone impedance is usually between 8-600 ohms, with the standard around 32 ohms becoming more common.
The impedance of the audio source is usually very low, usually less than 4 ohms, and in many cases close to 0 ohms,
But for dedicated tube amplifiers, especially output transformerless (OTL) types, it can go up to 120 ohms or more.