| Typical test index | 
| Frequency response | It is an important parameter of power amplifier to reflect the processing ability of different frequency signals | 
| Distortion curve | Total harmonic distortion, abbreviated as THD. The curve results are obtained by analyzing the higher harmonic distortion of the signal. | 
| Abnormal sound factor | Abnormal sound refers to the squeaking or buzzing sound of the product during the working process, which can be judged by this indicator. | 
| Single point value | The value at a certain frequency point in the result of the frequency response curve is generally used as a data point at 1kHz. It can effectively measure the working efficiency of the speaker under the same input power. |