The Enhancement Algorithm Of Speaker Abnormal Sound And Its Feature Analysis

Speaker is a common electroacoustic transducer,it include a wide range of items and be applied extensively in different fields.As people's living standard enhances unceasingly,the requirements of speaker sound quality are also rising.Speaker abnormal sound test is a measurement and listening check process of speaker's sound quality while designing and producing.The test result directly related to speaker's sound quality and product quality.At present,main speaker abnormal sound test way of domestic speaker manufacturers is listening speaker's sound directly by human.But because of the individual subjective differences of listeners and the noise influence of work environment,it is difficult to ensure accuracy and stability of test result.Therefore this thesis proposes an enhancement algorithm of speaker abnormal sound.While keeping normal harmonic response signal of speaker,enhance abnormal sound signal due to speaker's defect.So that the human ear can distinguish abnormal sound of fault speaker more easy.On the one hand it can reduce the working strength of listener,on the other hand it also can ensure the accuracy and consistency of test result.After characteristics analysis and pattern recognition of enhanced abnormal sound signal,the fault reason of abnormal speaker can be preliminary judged.Consequently the speaker produce ways will be improved.This thesis first introduces the basic structure,working principle and main performance index of speaker.Then introduces the common fault types and its causes of abnormal sound speaker.Combining previous scholars research results,the basic principles of speaker abnormal sound test technology are introduced.Secondly,the enhancement algorithm of speaker abnormal sound based on fundamental frequency offset is proposed.The basic principle,technique process,experiment platform of abnormal sound enhancement technology and the selection of speaker abnormal sound test stimulate which include step sweep signal and chirp signal are introduced.Aiming at fundamental frequency information of speaker response signal which used in this algorithm,multiple fundamental frequency extract algorithm have been researched by time domain and frequency domain analyze method.Frequency,amplitude and phase information of speaker response have been received successfully.Finally,combining with specific example,the abnormal sound enhancement algorithm of speaker response stimulated by pure tone signal and sweep signal are introduced.And the endpoint detection algorithm used in speaker abnormal sound test is introduced,endpoint information of speaker response signal have been extracted successfully by various methods.After abnormal sound enhancement process to normal loudspeaker and abnormal loudspeaker response signal,fundamental frequency signal have been offset successfully and abnormal sound of speaker have been enhanced.By analyzing enhanced abnormal sound signal of fault speaker,some common fault type speaker abnormal sound's time domain and frequency domain characteristics have been achieved.Consequently,it prepared theoretical knowledge for fault recognition algorithm of speaker abnormal sound.