Advantages and disadvantages of high impedance headphones

Advantage:1. High-impedance headphones have high signal-to-noise ratio of the systemAny amplifier circuit has a noise floor, that is, the noise measured by the ...

Mar 01,2022 | Magical

Advantage:

1. High-impedance headphones have high signal-to-noise ratio of the system

Any amplifier circuit has a noise floor, that is, the noise measured by the instrument at the output end after the input end is short-circuited, basically does not change with the change of the clock position of the volume knob,noise cancelling earbuds and earphones， that is, a fixed voltage value. Therefore, according to Ohm's law, the simple result can be obtained:

High impedance: low noise power

Low resistance: high noise power

Friends who use the on-board sound card to push low-impedance headphones can confirm that they have a deep understanding of this.

2. High-impedance headphones minimize negative effects of amplifier midpoint DC bias potential

OCL

The circuit is the main structure of the power amplifier, when the input is zero, its output is not absolutely zero. Be careful friends found that when you plug in the headphones, you will find that you will hear the electricity

The presence of this midpoint offset in the amplifier manifests itself in voltages that are often in the order of a few millivolts or even tens of millivolts. Under the action of this working voltage, the voice coil of the earphone will be slightly offset and its movement in the magnetic gap will

The initial position where the effective travel of the earphone is reduced and the distortion is increased. Under the same offset voltage, the voice coil offset of high-impedance headphones is relatively small.

3. High-impedance dynamic is good. The high-impedance version of the same series of headphones has the same number of voice coil turns, but the wire is thinner, the quality of the vibration system, that is, the inertia, is reduced, and the ability to follow weak and fast signals is increased. Here, high resistance = high grade.

4. From the perspective of amplifier distortion: the high-impedance headphone has a light load, the amplifier works relatively in a low distortion state, and the sound quality is good.

5. When there are extreme and unexpected situations such as amplifier failure, volume knob suddenly turned on, high impedance headphones have better tolerance and will not burn out.

disadvantage

1. High impedance headphones are difficult to drive and have low compatibility with portable devices

portable devices can use batteries with low voltage; at the same time, it is necessary to consider the battery life, and the output signal power technology of the circuit is limited. These conditions make high-resistance headphones harder to perform on these devices.

But in reality, the portable unit is a patented earbud that's almost identical to larger diaphragm headphones. High impedance is not the only factor, or even the most important factor. The difficulty of the driven development of headphones is determined by the following main factors in order:

The larger the diaphragm area, the harder it is to push;

Sensitivity (db/mW);

Impedance

Diaphragm area ranks first. At best, the resistance has played the role of "helping the evil".

2. The high-impedance headphones have many voice coil turns and thin wires, which bring some negative factors for students

Due to the large number of coil turns and thin wires, the inductance and distributed capacitance of the voice coil increase, which brings additional distortion to the headphone system;

Manufacturing and assembly of the earphones becomes difficult due to the thin wires, and high-resistance earphones tend to break the leads of the voice coil in humid environments.