济南汽车音响http://www.sdcarmusic.com/前级讯号控制就是在后级之前，我们一般将功放称为后级，所以在音源与功放之间，所有对于音乐讯号的处理机件，都称为前级。例如济南汽车音响主机上对于音量大小的控制，就是属于前级的部分，它控制的就是讯号的强弱度。
Jinan car stereo preamp signal control is, before the stage, we will generally be called post-stage amplifier, so between the sound source and amplifier, all the music signal processing parts are called before the class. Jinan such as car audio console for controlling the volume, that is part of belonging to the former level, the strength of which is controlled by signals.

其它音响器材中，较常看到的济南汽车音响前级控制部分，还有高音与低音的调整、左右平衡、前后音量调整、以及Loudless响度控制。此外比较复杂的还有音频均衡器(EQ)，其功能和床头音响经常见到的、具有多段频率调整音色、还会显示不同图案屏幕的功能相同。
Other audio equipment, more often seen in Jinan car stereo preamp control section, as well as treble and bass adjustment, left and right balance, front and rear volume adjustment, and Loudless loudness control. In addition there are more complex audio equalizer (EQ), its functions and bedside sound often seen with multi-frequency tone adjustment, but also show the same pattern of the screen different functions.

济南汽车音响http://www.sdcarmusic.com/数字音效处理器DSP也是许多主机的标准配备，简单说来就是模拟体育馆、舞厅或是音乐厅等空间的声音特性。总而言之，凡是有关于讯号的处理或调整的机构，就是前级。
Jinan Car Audio digital sound processor (DSP) also come standard with many hosts, simply that simulate gymnasium, ballroom, concert halls and other spaces or sound characteristics. In short, where there are about treatment or adjust the signals of the body, it is the former level.