Abstract: this paper discusses a kind of through the use of the means of timbre regulator to adjust the cone speaker unit 2, 3 times the method of harmonic distortion. This paper discusses the different types of sound regulator are evenly coated in low-frequency speaker cone basin after surface and dry, observe its for two or three times the different effects of harmonic distortion, is obtained using the method can effectively regulate the speaker unit 2, 3, the conclusion of time harmonic distortion. For different types of sound regulator in speaker unit after its evaluation of the impact of subjective listening opinion also has carried on the induction analysis, this paper discusses the objective parameter change on the influence of subjective listening characteristics. Lists several practical application cases for reference.

　　Key words: adjust; Low-frequency loudspeaker unit; 2, 3 times harmonic distortion; Objective parameters; Subjective listening

　　The introduction

　　Speaker unit and a speaker system of 2, 3 times harmonic distortion is direct and obvious impact on listening [1].

　　How to effectively regulate simple low-frequency loudspeaker unit 2, 3, harmonic distortion, is the focus of this paper.

　　This article will use the three types of "sound regulator" of low-frequency basin speakers sound cone surface coating, measured before and after coating tone regulator of the low-frequency loudspeaker unit 2, 3 times harmonic distortion of objective parameters to analyze the regulation of its actual effect; Also on the subjective listening, in order to investigate their influence on subjective listening characteristics.

　　1 coating tone regulator for low-frequency speakers after 2, 3 times the influence of harmonic distortion characteristics

　　1-1, after coating tone regulator for each unit of 2, 3, the influence of harmonic distortion

　　USES three same 12 inch speaker unit, the paper plates elastic wave, etc. Are all made in China, in its sound plate surface evenly coated respectively 5 g sound regulator, dry after 10 days 2 and 3 of harmonic distortion measurement, the result is shown below.

　　(note, this article measured input voltage is 2.83 V, measurement microphone distance is 1 m, anechoic chamber volume is 240 m after.)

　　Type 1-1-1, regulating method 1, coated C010815 timbre regulator.

　　Coating method is to evenly on the face of the sound plate coating type 5 grams C010815 sound regulator, their effects on 2, 3 times harmonic distortion is shown in figure 1: adjust the method 1, coating type C010815 timbre regulator for 2 times after the influence of harmonic distortion; Figure 2: adjust method 1, coating type C010815 timbre regulator for three times after the influence of harmonic distortion. Visible, generally two harmonic distortion at various frequencies increase; In addition to three harmonic distortion in 55 hz, there were notable increases from 400-800 hz frequency range, mostly in the rest of the band is reduced.

　　1-1-2, can be seen from the figure 1, the frequency response characteristics of the unit before and after the adjustment basically remain unchanged. (note, although there is no mark in the following figure 3-6 frequency response characteristics, but also has the characteristics of)

Figure 1 adjustment method 1, coating type C010815 timbre regulator for 2 times after the influence of harmonic distortion

　　Type 1-2-2, regulating method 2, coated D11B0420 timbre regulator.

　　Coating method is to evenly on the face of the sound plate coating type 5 grams D11B0420 sound regulator, their effects on 2, 3 times harmonic distortion is shown in figure 3: adjust method 2, coating type D11B042 timbre regulator for 2 times after the influence of harmonic distortion; Figure 4: adjusting method 2, coated D11B0420 type sound regulator for three times after the influence of harmonic distortion. Visible, total harmonic distortion in a downward trend, 2 times 3 times harmonic distortion in the vicinity of 500-600 hz frequency increase, the rest of the band basic is declining.

Figure 3 adjustment method 2, coated type D11B042 timbre regulator for 2 times after the influence of harmonic distortion

　　Figure 4 adjustment method 2, coated type D11B0420 timbre regulator for three times after the influence of harmonic distortion

　　The 1-2-3, adjust method 3, coated C14B0416. 6 type sound regulator.

　　Coating method is to evenly on the face of the sound plate coated 5 grams C14B0416. 6 sound regulator, their effects on 2, 3 times harmonic distortion is shown in figure 5: adjust method 3, coated C14B0416. 6 type sound regulator for 2 times after the influence of harmonic distortion; Figure 6: adjust method 3, coated C14B0416. 6 type sound regulator for three times after the influence of harmonic distortion. Visible, two harmonic distortion increase, 3 times harmonic distortion in more than 600 hz frequency decrease more.

　　Figure 5 adjustment method 3, coated C14B0416. 6 type sound regulator for 2 times after the influence of harmonic distortion

　　Figure 6 adjustment method 3, coated C14B0416. 6 type sound regulator for three times after the influence of harmonic distortion

　　2 adjust the low frequency harmonic distortion speaker unit 2, 3 times after listening

　　2-1, to judge the subjective listening in the form of a system

　　Considering the low-frequency loudspeaker unit ultimately is to appear in the form of used in the system, so in a way that is integrated into a system of the unit subjective audition is appropriate, and not just individual listen to the sound units. Use one without coating tone regulator bass unit and 3 respectively coating composed of 3 kinds of sound regulator bass unit 4 speaker system frequency response characteristic and total harmonic distortion of the features shown in figure 36 a speaker system frequency response characteristic and total harmonic distortion characteristic of [5]. The speaker system is 2 points frequency, frequency points is 1.5 k Hz.

　　To be sure, the characteristics of frequency response characteristics of the speaker system is based on data [4] and adjustment, design style is suitable for mass entertainment.

　　Figure 7 4 speaker system frequency response characteristic and the total harmonic distortion characteristics

　　2, the evaluation opinions of subjective listening

　　USES comparison method to use no coating timbre regulator unit of the system as a sample and use of coated unit system for listening, the contrast, listening opinions are given respectively, and the other on generalizations. Listen point is in the listener's work environment, such as their work, design, or audition room, etc.

　　Regulator of timbre of the three subjective listening comprehensive opinion is:

　　1, using C010815 tone adjustment materials: low frequency dive deep and intermediate frequency with the feeling of stability, the overall tone coherence and bright. More music taste as a whole.

　　2, using D11B0420 tone adjustment materials: low-frequency a sense of strength and elasticity, and clear sense of low frequency and intermediate frequency. Feel the smell of entertainment as a whole.

　　3, using C14B0416. 6 tone adjustment material: overall owe smooth feeling, intermediate frequency slightly clean and loose, vocal performance particularly plump. When singing more "fruity, full" feeling.

　　3 adjust the low frequency harmonic distortion speaker unit 2, 3 times after conclusion and discussion of the impact of the subjective and objective parameters objective parameter change on the influence of subjective listening characteristics

　　3-1, the influence of objective parameters

　　A moderate amount of coated paper cone surface sound regulator on the total harmonic distortion and after 2, 3 times harmonic distortion produced significant influence, different timbre of the regulator on the influence of different frequencies have different characteristics.

　　3-2, the conclusion of the impact of subjective listening

　　Different models of timbre regulator after coating in low-frequency loudspeaker unit sound basin, the different influence on its subjective listening, these effects on both the overall tone change, there is also a partial tone adjustment.

　　3-3, analysis after the speaker sound cone surface coated timbre regulator objective parameter change on the influence of subjective listening characteristics

　　C010815 type sound regulator in the increase of its two harmonic distortion and the decrease of the harmonic distortion, 3 times mean that subjective listening easier to accept its overall sound performance?

　　Listening D11B0420 type of low-frequency dynamics sense is stronger, but owe music; Most of the audience think its suitable for use in a karaoke bars and other places of entertainment. On the technical parameters, including frequency has increased the total harmonic distortion of also have reduced frequencies, two harmonic distortion is basically increased, harmonic distortion in 3 times more than 600 hz frequency decrease.

　　C14B0416. 6 sound regulator, listening on the unit's spectrum is clean and loose, good vocal accept, this is an objective parameter corresponding to the benefits of low distortion. On the objective indicators, it twice harmonic distortion increase; But three significantly lower harmonic distortion, especially near the 1 k Hz frequency harmonic distortion reduce the proportion of 3 times larger. On this basis, might as well reference [1]

　　In the analysis of the NTH harmonic distortion: for general people, the odd harmonic distortion more easily than even order harmonic distortion.

　　4 introduce some cases for your reference

　　4-1, guangzhou a company (the company to operate the entertainment sound engineering design and installation debugging) using the production of E? A 12 inch low frequency speaker unit, the unit of paper cone slants thin, medium frequency good sweet degree; User request improvement is: 1, low frequency more resilient, drums "cartridge" give more powerful; 2, intermediate frequency strong some, especially in the "up" when you sing.

　　Tone adjustment scheme 1 is, on the edge of the paper cone back with 1.5 g C010415 type regulator, inside the dust cap with 1 g C14B0416. 6 type regulator; Listening is low frequency has good elasticity, intermediate frequency and 800 hz 100 thick warm, but feel a concave 400 hz. So try to plan 2: on the edge of the paper cone back with 1.5 g D11B0420 sound regulator, inside the dust cap with 1 g C14B0416. 6 type regulator; Listening is: 400 hz not concave. End customer to see the two purposes, respectively, in order to meet with the need of the use of different occasions and peripheral equipment performance. As to the flaws in 1 package, for 400 hz listening sag (actual frequency response characteristic is no sag) appears to owe the problem of "small bottom spirit", the use quantity of users by adjusting the tone regulator and coating position is solved.

　　4-2, foshan city, guangdong province a company (the company produce the speaker system) using production of B in Spain? Card of a 12 inch bass unit, the unit is half SongYa paper cone, the outer surface of the sound basin has by basin of base paper production plants with waterproof coating. The department to improve the product's market competitiveness and meet the personalized and differentiated to timbre of high-grade products, to put forward the improvement of the unit requirements are: 1, lower frequencies in the dry, thick is better to run a bit, in order to more adapt to the entertainment market (singing megaphones, etc.); 2, low frequency increase elasticity.

　　Sound of the bass unit to adjust the test plan is for the first time: plan 1, in the sound basin type surface besmear C010215 timbre regulator; Scheme 2, in the basin type surface besmear D11A0420 timbre regulator. Listening as a result, the plan 1 tone color is bright, medium frequency careful, low-frequency dive deeper, music expressive features; Low frequency plan 2 more flexibility and strength, the thickness of the medium frequency strong feeling. More than just a test for the first time, in the actual product type test, change department, creative use of the performance of the unit paper plates and material characteristics of different sound regulator, achieve success together. This product has first batch production, the supply of high-end market.

　　4-3, guangzhou panyu area a company (the company is production loudspeaker unit also produces the speaker system) in the production of a certain type of 12 inch bass unit, use the UKM brown paper bowl, the paper pot handle hard. Adjust the sound requirement is: 1, the low-frequency unit itself is powerful, but tight; 2, the convergence of the frequency of penetration (producer sic, meaning refers to the "medium frequency cacophony"); 3 enhance the music.

　　Solutions, coating type C010215 sound regulator, weight? G on disk. The products have been batch production.

　　4-4, guangzhou D12 from a production - 4 l 12 inch bass unit, its use in the UK UKM black paper cone, the thickness of 0.7 mm. Adjust the sound requirement is: 1, the extension of low frequency, best can increase the elasticity; 2, the promotion music expression.

　　Solution: in the basin of sound surface evenly coated type 6 grams C010415 timbre regulator. The unit also coated C010815 and in the process of test C010215 and D11B0420 sound regulator, but ultimately chose C010415 tone regulator.

　　After a period of time after use, in order to expand the unit USES, main is to let the unit in the band more "highlight" to adapt to the taste of the Chinese entertainment market. In dust cap with 1 g C14B0416. After six sound regulator, listen to the feeling of intermediate frequency plumpness improve, have the feeling of convex rise, low frequency than before more "focused" feeling. 1204 the lda model unit in the unit (see data [4] P40, 6).

　　Four to five, a company in guangzhou, the company specializing in the production of the speaker unit) production of a certain type of 12 inch bass unit, make the LC paper plates, the thickness of thin. The unit and analytical ability and good music, put forward the improvement of user demands is: 1, increase the thickness of the medium frequency sense; 2, to improve the amount of low frequency and elastic.

　　Solution: 1, the use of C14B0416. 6 type thick sound regulator of intermediate frequency run, weight? G in a certain position; Type 2, use A16B0416. 6 sound regulator improve the amount of low frequency, quantity? G to sound plate; Type 3, use D11B0420 timbre regulator active feeling, enhance the flexibility of low frequency and the overall weight? G apply plate back a certain position. The product has been mass production, the main supply of high-end entertainment market.

　　4-6, a company in guangzhou from abroad (the company produce the speaker system) the use of custom of a certain type 12 inch low-frequency speaker unit

　　Speaker system for China's entertainment market, the company was impressed with the accuracy of the system of sound, but also because the system owes low-frequency elastic feeling and intermediate frequency active feeling, there has been no finalize the design. The bass unit China agent in conjunction with foreign manufacturers of designers repeatedly to the department of information and provide the improved sample, but failed to satisfy the user.

　　Solution: surface evenly coated in sound set? G type D11B0420 sound regulator, coated outside the sound plate back? G type C010815 timbre regulator. The company satisfied with the improved effect.

　　5 conclusion

　　Such as the need to set or close to finalize the design phase of the speaker unit or speakers adjust sound, can consider using sound regulator to adjust the 2, 3 times harmonic distortion so as to achieve the purpose of changing listening.

　　References:

　　[1] yi-zhen wang. Practical speaker technology handbook [M]. Beijing national defence industry press, 2003.

　　[2] of the People's Republic of China national standard system equipment Part 5 speakers main performance testing methods of GB/T 12060.5 2011

　　[3] YuJin yuan. The speaker design and production of [M]. Guangzhou guangdong science and technology press, 2006.

　　[4] han-bo deng. Entertainment rooms with speaker system design and the use characteristic study [J]. Journal of electroacoustic technology, 2013 (12) 35 to 41

　　[5] han-bo deng. Sound regulator effects on speaker features. The audio engineering academic exchange conference of 2015"