Audio lines are generally used for Line In and Line Out. They pass signals with low current and low power, and have high impedance and are easily disturbed. Therefore, they are generally shielded lines, but the lines are generally thinner; speaker lines
, It is the wire used to connect the final stage of the power amplifier to the speaker, directly passing the power signal, and because of the large current, the wire is usually very thick, and in order to ensure high-frequency passage and reduce resistance attenuation, most of them are silver-plated, gold-plated copper or copper-silver alloy Wire.
Note that the thickness of the wire mentioned here does not refer to the sheath, but to the effective wire core in the middle.
The current signal circulating in it is much larger than the video line and audio line mentioned above. Because of the large signal amplitude, this type of line often has no shielding layer. For this type of wire, the key is to reduce its resistance, because the output impedance of modern power amplifiers Very low, so the requirements for speaker wires are also increased, such as the selection of large cross-sectional areas or multi-strand wires. Wires range from pure copper to silver wires. The more expensive speaker wires are oxygen-free copper speaker wires. few.
HIFI speakers are used to restore the recording sound field with high fidelity, so there must be sufficient guarantee for the lossless transmission of audio signals. Generally, transmission lines have different impedances for different frequency signals. This characteristic is manifested in poor sound quality in sound restoration. For this reason, people have produced a high-end speaker connection line called an intelligent signal line. The characteristics of this line are The signal is divided into two channels according to the frequency. The outer layer of a certain thickness passes the signal above 5KHZ, and the signal below 5KHZ is transmitted through the inner layer of the line. This greatly improves the frequency characteristics of the transmission line and makes the replayed sound The effect is good. However, the price is also very expensive. Most of the audio cable brands mentioned above also produce fever speaker cables.
Look at the choice of speaker wires from a technical point of view. A wire that is too thin will obviously not have a good result, because the resistance of a thin wire is high, and more power will be consumed on the resistance of the wire, especially the loss of bass. Although the resistance of the wire that is too thick is small, it causes a waste of materials and money. It is generally considered that the loss on the wire (insertion loss) is tolerable below 0.5dB. In this part of the circuit from the power amplifier output to the speaker, the impedance of the speaker, the length of the wire, and the thickness of the wire are all important. The general method is to calculate the thickness of the wire based on the length of the wire and the impedance of the speaker. There are many types of wire rods in the market, and the prices vary greatly. Generally, high-quality oxygen-free copper is used. In particular, we remind everyone to pay attention to the fact that there are many counterfeit wire rods on the market, so you must pay attention when purchasing. We can distinguish from the structure, material and appearance of the wire: the fever-grade wire is made of relatively high-purity ES-OCC (oxygen-free single-crystal copper) or OFEC (oxygen-free electrolytic copper) to make conductor copper wire, which has It has the characteristics of flexibility, tensile strength and bending resistance, while the counterfeit wires use ordinary copper thin wires as the conductor material. In addition, the authenticity of the wires can be correctly judged from the appearance of the wires. Generally, authentic brands of fever wires It has a trademark and a typeface printed very clearly, and it is difficult to rub off. The appearance of the craft is exquisite and standardized.