Weak current College】 【AV system and the differences between a HI-FI system.

First, the specification of different examination

1 frequency response range: HI-FI system requirements 20HZ ~ 20KHZ +/--3dB for AV system, Dolby AC-3DTS each channel should be 35HZ ~ 18KHZ subwoofer frequency range of 20 ~ 200HZ

2-to-noise ratio (S/N audio system for playback of music, in addition to the musical signal, there are no expected voice, call it noise, including thermal noise and ripple noise and mechanical noise, etc. SNR is the power of the signal level and noise level power ratio, the higher the value, the better. HI-FI system requirements in more than 90 decibels, AV system reaches 85 decibels on it

3 dynamic range: dynamic range refers to the audio system when you replay the biggest mupo and static system noise power output when the ratio of the value, expressed in decibels. For HI-FI system requirements 90 decibels or higher, AV system is more than 100 DB.

4 distortion: distortion is the enemy of HI-FI system. In a sense, the importance of even well beyond the first three indicators. In General, HI-FI system total distortion should be less than 1.5% AV system total distortion also should not be greater than 3%

Second, the power amplifier

AV system amplifier in the structure and function and HI-FI amps are completely different. AV amplifier features larger capacity, to meet with wide dynamic range compression, loud program requirements. HI-FI amplifier design concise, so as not to cause modulation distortion; minimize the zoom factor. AV amplifier and HI-FI amplifier in timbre and sound are also significant differences. HI-FI amplifier is to resolve outstanding, beautiful tone color force, music that force is famous for its rich and AV amplifier is a large dynamic feet do not have a soft, low frequency, powerful sound field. Both have their advantages, not replace each other.

3. speaker

HI-FI system, although only two speakers, but also pay attention to the quality of life and perfect, require a high level of fidelity and transient response. And AV speakers is rendering large scenes representing large dynamic, and therefore do not emphasize the timbre nuanced, with great accuracy. But sensitivity on AV speakers require higher because AV systems require powerful sound pressure, such as HI-FI speakers because the sensitivity low and unable to reach zoom dynamic signals easy clipping distortion. AV speakers generally exceed 90 DB sensitivity, some even have 92 DB.

15th set power amplifier and speaker system adaptation


Amplifier and speaker system adapter, principally in impedance adaptor, power adapter, sensitivity adaptation and timbre matching, etc.

First, the impedance adapter

Power amplifier and speakers to adaptation, impedance matching is the most important sound of nominal impedance should and amplifier rated output impedance equal or similar. Transistor amplifier is low impedance output circuit; electron tube amplifier is a high-impedance output circuits of the speaker impedance value requires very strict. But transistor low impedance output amplifier still load impedance values presented a de facto requirement. For example, the original design of the amplifier output load should be 8-Europe, tend to be the ideal amplifier circuit, and with 16 European speakers, its output power approximately halved, but with 4 Europe speakers, the output power is doubled. But most of the power amplifier are not the ideal top-tier device, the output resistance are not possible infinite loop in small, zoom is not possible to provide adequate current gain, regulated power supply is not possible to provide adequate operating current. When this power amplifier access too low-impedance speaker, transient characteristics go bad, the distortion level increases, the greater the power output, but the value is not caused by power. When the amplifier connection higher than the rated load impedance speakers, rated output power is reduced, the impact on other performance indicators is not great; but if the power voltage margin is not big, you may follow not reached at rated power, has occurred overload distortion.

2. power adapter

Amplifier's rated output power and speaker of the rated input power should be adapted to each other. Amplifier power rating should be slightly larger than the speakers of the rated power of 1/4 for example, 125W power amplifier to drive the speakers around 100W. Practical speaker has certain overload capacity, its allowed values are rated on drop 1.5 times. Transistor amplifier overload ability strong, overload, its variation is less distortion.

3. sensitivity adaptation

Amplifier output power is not the same as the driving force for sound. Powerful driving force and power amplifier output power, also with other factors, especially with the sensitivity of the sound. Speaker sensitivity is decision power amplifier output power value. Currently, the high sensitivity of the speaker has reached 95dB/W/m are even beyond 100dB/W/m sensitivity and low sound only 82 ~ 86dB/W/m many used to listen to music in HI-FI sound sensitivity is low (about 82 ~ 84dB/W/mAV amplifier should, as far as possible, with high sensitivity (90dB/W/m left and right) speakers. But sensitivity is too high, the tone color of thin, too bright, reproduce music details and charm. Speaker sensitivity disparity on speaker driver requirements of Suzhou has a significant impact. Speaker sensitivity each 3dB reduction in order to achieve the same sound intensity, power amplifier output power is doubled. For example, the speaker sensitivity by 90dB/W/m drops to 87dB/W/m original use 50W amplifier, the power amplifier 100W power increased to sound the same, to produce the same sound pressure level, drive power should be increased to 16 times; when speaker sensitivity are not identical, the drive power is not the same; the high sensitivity of the speakers can use a smaller drive power, can achieve the required volume. Audio equipment collocation, speaker sensitivity adaptation issues is very important.

4. sound adapter

Equipment of timbre subjectivity, different people like different timbres. Timbre matching need to consider several factors, often requireListen carefully, more taste, the ability to accurately feel the sound characteristics of timbre.