In professional audio systems, the matching of professional power amplifiers and professional speakers, in addition to the soft timbre (timbre collocation is often said to be soft and hard, it is based on the designer's design and materials for the tone color, and has the characteristics and personality ), there are some hard collocations on technical indicators. Soft collocation is based on accumulated experience and personal preference, while hard collocation is determined by data and basic technical common sense. The following is a brief description of the four major "hard collocation" related aspects.
1. Impedance matching
1. When the tube amplifier (tube amplifier) is matched with the speaker, the output impedance of the amplifier should be equal to the impedance of the speaker, otherwise it will reduce the output power and increase the distortion. Fortunately, most amplifiers have variable output impedance matching interfaces such as 4-8-16 ohms, and impedance matching with speakers has become simpler.
2. For the matching of transistor power amplifier (stone machine) and speaker impedance
① When the speaker impedance is higher than the output impedance of the power amplifier, there is no other effect except for the different degree of reduction of the output power.
② When the speaker impedance is lower than the output impedance of the power amplifier, the output power will increase proportionally, and the distortion will generally not increase or the increase is negligible. But the speaker impedance cannot be too low during matching, such as as low as 2 ohms (referring to when two 4 ohm speakers are connected in parallel). At this time, only the power amplifier has a large margin, and the high-power tube and multi-tube parallel push-pull with good performance should be used. It has no effect on such power amplifiers.
On the contrary, ordinary power amplifiers are not rich, and the pcm and lcm of the power amplifier tubes are not large. When the volume is turned on again, the distortion will increase significantly, and the box will be destroyed in serious cases. Pay attention.
2. Power matching
1. In principle, when the rated power of the speaker is inconsistent with the rated power of the power amplifier, for the power amplifier, its power is only related to the speaker impedance, and has nothing to do with the rated power of the speaker. Regardless of whether the speaker power is the same as the power amplifier power, it has no effect on the work of the power amplifier, but is only related to the safety of the speaker itself.
2. If the speaker impedance meets the matching requirements, and the withstand power is less than the power of the amplifier, then the driving power is sufficient, which sounds very comfortable. This is what it is often said that the reserve power of the power amplifier must be large in order to fully express all the connotations of music, especially the low frequency part of the music, which is more vivid and powerful. This is a good match.
3. If the rated impedance of the speaker is greater than the rated power of the power amplifier, although both can work safely, at this time, the power amplifier is not enough to drive the power, and the loudness will be insufficient. It often appears that it has been turned on to a saturated state, and the distortion is aggravated. Powerless. This is a poor match.
Three, match according to the damping coefficient
For selecting a pair of hi-fi speakers, there should be the best specific resistance requirements (responsible speaker manufacturers should provide this data, which refers to the requirements for the damping coefficient of the power amplifier. The point is to make it clear that this is the case. For speakers, what is the damping coefficient of the power amplifier required?).
In general, it is better for the damping coefficient of the power amplifier to be higher. When the damping coefficient of the low-end power amplifier is less than 10, the low-frequency characteristics, output characteristics, and high-order harmonic characteristics of the speaker will be deteriorated. (The damping number of household power amplifiers is generally between tens to hundreds).
Fourth, the matching of wires
There are many imported fever lines and nerve lines, which cost more than 10,000 yuan, followed by thousands to thousands of yuan (of course, there are also less than 100 yuan), and the effect of use is a matter of opinion. In general, a good cable will improve the lack of a certain system in audio equipment. Its transmission theory is too complicated to say, it can only be briefly described.
The material and structure of the transmission line determine three important parameters, namely resistance, capacitance, inductance (and electromagnetic effect, skin effect, proximity effect, reactance, etc.). Don’t look at the small gaps in these parameters, which will directly affect the audio system frequency. Characteristics, damping characteristics, signal rate, phase accuracy, and timbre orientation and sound field positioning, etc. Its main function is high-speed transmission (to minimize signal loss), anti-vibration, anti-noise, anti-interference (mainly radio wave rf1 radio frequency interference and em1 electromagnetic wave interference, etc.).