| 
 Test index 
 | 
Abbreviation | 
 Key function 
 | 
 Unit 
 | 
| 
 Frequency response curve 
 | 
 FR 
 | 
 Reflecting the processing ability of different frequency signals is one of the important parameters of audio products 
 | 
 dBSPL 
 | 
| 
 Distortion curve 
 | 
 THD 
 | 
 The deviation of signals of different frequency bands in the transmission process compared with the original signal or standard 
 | 
 % 
 | 
| 
 Equalizer 
 | 
 EQ 
 | 
 A kind of audio effect device, mainly used to control the output size of different frequency bands of audio 
 | 
 dB 
 | 
| 
 Power VS distortion 
 | 
 Level vs THD 
 | 
 The distortion under different output power conditions is used to indicate the output stability of the mixer under different power 
conditions 
 | 
 % 
 | 
| 
 Output amplitude 
 | 
 V-Rms 
 | 
 The amplitude of the external output of the mixer at the rated or permitted maximum without distortion 
 | 
 V 
 |