CN101588526B - Directivity optimization method of loudspeaker array - Google Patents

Abstract

The invention provides a directivity optimization method of loudspeaker array, the method includes following steps, a loudspeaker array with n loudspeaker units uniformly disposed on a straight line is provided, such that space between two adjacent loudspeaker is 1, total length L of the loudspeaker array is (n-1)*1; a test point p is provided, such that distance between the test point p and central point of the loudspeaker array is r, the level angle of the the test point p and central point of the loudspeaker array is theta, supposes distances between each loudspeaker unit and the test point p are respectively r1, r2, ...rn; determining sound pressure and reference sound pressure of the soundspeaker at one point in space; finally determining vertical directivity function of the soundspeaker array; setting directivity optimization condition of loudspeaker array, thereby optimized power coefficient is obtained. The directivity optimization method of loudspeaker array according to the invention can implement directivity widening of the loudspeaker array with simple design.

Description

The directivity optimization method of array speaker

[technical field]

The present invention relates to a kind of optimization method of array speaker, relate in particular to a kind of directivity optimization method of array speaker.

[background technology]

Array speaker has a wide range of applications, and also is the focus of electroacoustic area research.About the directivity optimization measure of array speaker, mainly contain logarithm spatial separation arranged array loud speaker at present, utilize quadratic residue sequence to give each loudspeaker unit different time delay signal.The directive property that realizes array speaker strengthens.

But last optimized Measures complex design, radiation efficiency is low, perhaps in shortcomings such as some frequency range inefficacies.

Therefore, be necessary in fact to propose a kind of directivity optimization method of new array speaker.

[summary of the invention]

The technical problem that the present invention solved provides the directivity optimization method of the array speaker that a kind of directive property that realizes array speaker strengthens.

According to the above-mentioned technical problem that needs solution, designed a kind of directivity optimization method of array speaker, this method comprises the steps:

Step S001: provide one to be evenly distributed on the array speaker on the straight line by n loudspeaker unit, make that the spacing of two adjacent loudspeaker units is l, the total length of array speaker is L=(n-1) * l;

Step S002: a test point p is provided, and the distance that makes its distance arrays speaker center point is r, with the level angle of array speaker central point be θ, the distance of establishing each loudspeaker unit distance test point p is respectively r ₁, r ₂,, r _nObtain loudspeaker unit at test point p, reference sound pressure during θ=0 ° and loudspeaker unit are in the synthetic total acoustic pressure of test point p

$\mathrm{Pn}=\mathrm{Wn}./\mathrm{Rn}.*\mathrm{Exp}(-i*2\mathrm{\π\; f}*\mathrm{Rn}/c).*\mathrm{Exp}(-i*2\mathrm{\π\; f}*\mathrm{Tn}).*\mathrm{Exp}(-i*\mathrm{Pn})*\frac{2J_1\left(k\frac{d}{2}\mathrm{Sin}\mathrm{\θ}\right)}{k\frac{d}{2}\mathrm{Sin}\mathrm{\θ}},$ Wherein, f is a signal frequency, and c is the velocity of sound, and rn is signal delay time, and pn is a signal phase, and wn is the loud speaker source strength, and k is a wave number, and d is the loudspeaker unit bore, and the directivity optimization method of array speaker is chosen tn=0, pn=0; The final vertical directivity function of confirming array speaker; Through conversion loud speaker source strength wn; In conjunction with the output result of the vertical directivity of array speaker, confirm the vertical directivity of one group of array speaker of optimizing, try to achieve power match coefficient Wn=wn according to the source strength wn of loud speaker ²

Step S003: the optimal conditions of the directivity optimization method of setting array loud speaker, thus draw the power coefficient of optimization;

Wherein among the step S003, the optimal conditions of the directivity optimization method of array speaker comprises:

Step K 001: set and optimize exponent number, time of delay, signal phase, the loud speaker source strength provides a comparison module;

Step K 002: set first group of loud speaker source strength; Confirm first group of power coefficient; In ° scope of-90 °～θ～90; Draw first group of array speaker directive property curve under the power coefficient, the directive property value when from the array speaker directive property curve of first group of power coefficient, finding out θ=0 °, promptly first with reference to the directive property value with utilize comparison module to find out the maximum of directive property in-90 °～θ～-45 ° and 45 °～θ～90 ° scope; Promptly the first directive property value is calculated the first directive property difference;

Step K 003: set second group of loud speaker source strength; Confirm second group of power coefficient; In ° scope of-90 °～θ～90; Draw second group of array speaker directive property curve under the power coefficient, the directive property value when from the array speaker directive property curve of second group of power coefficient, finding out θ=0 °, promptly second with reference to the directive property value with utilize comparison module to find out the maximum of directive property in-90 °～θ～-45 ° and 45 °～θ～90 ° scope; Promptly the second directive property value is calculated the second directive property difference; And the like, set N ⁿGroup loud speaker source strength is confirmed N ⁿThe group power coefficient draws N ⁿArray speaker directive property curve under the group power coefficient is from N ⁿDirective property value when finding out θ=0 ° in the array speaker directive property curve of group under the power coefficient, i.e. N ⁿWith reference to the directive property value with utilize comparison module to find out the maximum of directive property in-90 °～θ～-45 ° and 45 °～θ～90 ° scope, i.e. N ⁿThe directive property value is calculated N ⁿThe directive property difference;

Step K 004: utilize comparison module to find out first directive property difference to the N ⁿThe maximum of directive property difference, thus confirm the power coefficient that this maximum is corresponding, the power coefficient of promptly optimizing.

Preferably; The directivity optimization method of said array speaker also comprises according to the power coefficient of optimizing; Obtain the array speaker directive property curve after the optimization under the different frequency; Thereby whether the initial selected optimization initial frequency of checking is optimum frequency, and then confirms that the power coefficient of optimizing is optimal selection.

Preferably, said is the directivity function of single loudspeaker unit.

The directivity optimization method of array speaker of the present invention can realize that the directive property of array speaker strengthens and simplicity of design.

[description of drawings]

The directive property comparison diagram of the array speaker before and after the optimization that Fig. 1 draws for the directivity optimization method of array speaker of the present invention.

The directive property comparison diagram of the array speaker of the optimization power coefficient that the directivity optimization method of Fig. 2 array speaker according to the present invention draws before and after frequency is optimized during for 2250HZ.

The directive property comparison diagram of the array speaker of the optimization power coefficient that the directivity optimization method of Fig. 3 array speaker according to the present invention draws before and after frequency is optimized during for 3000Hz.

The directive property comparison diagram of the array speaker of the optimization power coefficient that the directivity optimization method of Fig. 4 array speaker according to the present invention draws before and after frequency is optimized during for 4500Hz.

The directive property comparison diagram of the array speaker of the optimization power coefficient that the directivity optimization method of Fig. 5 array speaker according to the present invention draws before and after frequency is optimized during for 10000Hz.

The directive property comparison diagram of the array speaker of the optimization power coefficient that the directivity optimization method of Fig. 6 array speaker according to the present invention draws before and after frequency is optimized during for 15000Hz.

[embodiment]

Below in conjunction with accompanying drawing, the directivity optimization method of array speaker of the present invention is elaborated.

As shown in Figure 1; The directivity optimization method of array speaker of the present invention; Wherein array speaker is made up of n loudspeaker unit that is evenly distributed on the straight line, and the spacing of two adjacent loudspeaker units is l, and the total length of array speaker is L=(n-1) * l.The distance of test point p distance arrays speaker center point of the present invention is r, and the level angle of itself and array speaker central point is θ.The distance of in addition, establishing each loudspeaker unit distance test point p is respectively r ₁, r ₂,, r _nAny synthetic total acoustic pressure is P to loudspeaker unit in the space.

Utilize the cosine law, then

r1＝((L/2-L/(n-1)*0))^2+r^2-2*(L/2-L/(n-1)*0)*r*sin(θ))^0.5；

r2＝((L/2-L/(n-1)*1))^2+r^2-2*(L/2-L/(n-1)*1)*r*sin(θ))^0.5；

·

·

·

... (needing reversion after having crossed the array speaker central point)

·

·

rn＝((L/2-L/(n-1)*0))^2+r^2+2*(L/2-L/(n-1)*0)*r*sin(θ))^0.5

Vertical angle is that the acoustic pressure that the some test point of θ produces is to single loudspeaker unit at distance arrays loud speaker r place:

$\mathrm{Pn}=\mathrm{wn}./\mathrm{rn}.*\exp (-i*2\mathrm{\πf}*\mathrm{rn}/c).*\exp (-i*2\mathrm{\πf}*\mathrm{tn}).*\exp (-i*\mathrm{pn})*\frac{2J_1\left(k\frac{d}{2}\sin \mathrm{\θ}\right)}{k\frac{d}{2}\sin \mathrm{\θ}}$

F is a signal frequency, and c is the velocity of sound, and tn is signal delay time, and pn is a signal phase, and wn is the loud speaker source strength.

is the directivity function of single loudspeaker unit; K is a wave number, and d is the loudspeaker unit bore.

Then n loudspeaker unit the composite sound of test point arbitrarily downgrade into:

$P=\underset{n=1}{\overset{n}{\mathrm{\Σ}}}\mathrm{Pn}$

The θ angle is 0 when spending, and apart from the acoustic pressure of r place level point, also is that reference sound pressure is:

$P_{\mathrm{\θ}=0}=\underset{n=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{Pn}}_{\mathrm{\θ}=0}$

By the definition of directivity function, then the vertical directivity function of array speaker is:

$D\left(\mathrm{\θ}\right)=\left|\frac{P}{P_{\mathrm{\θ}=0}}\right|$

By above derivation, the vertical directivity function D (θ) of array speaker includes tn signal delay time, signal phase pn and loud speaker source strength wn.

The present invention; Choose tn=0 signal delay time, signal phase pn=0, through conversion loud speaker source strength wn, in conjunction with the output result of the vertical directivity of array speaker; Confirm the vertical directivity of one group of array speaker of optimizing; At last, try to achieve power match coefficient Wn, i.e. Wn=wn according to loud speaker source strength wn ²

Because the power coefficient of each loudspeaker unit all changes in the scope of definition, n loudspeaker unit has multiple power coefficient combination.As select each loudspeaker unit the definition power bracket in by N kind power coefficient combined situation, promptly optimizing exponent number is N, then the power coefficient combined situation of n loudspeaker unit has N ⁿKind.

Optimal conditions of the present invention is:

Step K 001: set to optimize exponent number and be N, time of delay tn=0, signal phase pn=0, the loud speaker source strength

provide a comparison module;

Step K 002: set first group of loud speaker source strength wn ₁, confirm first group of power coefficient Wn ₁, in ° scope of-90 °～θ～90, draw first group of power coefficient Wn ₁Under array speaker directive property curve, from first group of power coefficient Wn ₁Array speaker directive property curve in directive property value when finding out θ=0 °, promptly first with reference to directive property value D _Q1With utilize comparison module and find out the maximum of directive property in-90 °～θ～-45 ° and 45 °～θ～90 ° scope, the i.e. first directive property value D ₁, calculate the first directive property difference D _M1=D ₁-D _Q1

Step K 003: set second group of loud speaker source strength wn ₂, confirm second group of power coefficient Wn ₂, in ° scope of-90 °～θ～90, draw second group of power coefficient Wn ₂Under array speaker directive property curve, from second group of power coefficient Wn ₂Array speaker directive property curve in directive property value when finding out θ=0 °, promptly second with reference to directive property value D _Q2With utilize comparison module and find out the maximum of directive property in-90 °～θ～-45 ° and 45 °～θ～90 ° scope, the i.e. second directive property value D ₂, calculate the second directive property difference D _M2=D ₂-D _Q2And the like, set N ⁿGroup loud speaker source strength

Confirm N ⁿThe group power coefficient

Draw N ⁿThe group power coefficient

Under array speaker directive property curve, from N ⁿThe group power coefficient

Under array speaker directive property curve in directive property value when finding out θ=0 °, i.e. N ⁿWith reference to directive property value D _Q2With utilize comparison module and find out the maximum of directive property in-90 °～θ～-45 ° and 45 °～θ～90 ° scope, i.e. N ⁿThe directive property value

Calculate N ⁿThe directive property difference $D_{m{N}^n}=D_{N^n}-D_{q{N}^n};$

Step K 004: utilize comparison module to find out the first directive property difference D _M1To N ⁿThe directive property difference

Maximum, thereby confirm the power coefficient that this maximum is corresponding, the power coefficient of promptly optimizing.

Embodiments of the invention:

Selected array speaker length overall L=0.176m, loudspeaker unit diameter d=0.014m, loudspeaker unit number n=12, measuring distance r=1m, optimization initial frequency f=6000HZ and optimization exponent number N=8.Draw the array speaker directive property curve that is not optimized processing, shown in the solid line among Fig. 1.

The power coefficient of optimization that finally draws this execution mode according to optimal conditions of the present invention is following:

W1＝0.1；W2＝0.2；W3＝0.6；W4＝1；W5＝1.2；W6＝1.44；W7＝1.44；W8＝1.2；W9＝1；W10＝0.6；W11＝0.2；W12＝0.1w；。

Then under the power coefficient of this optimization, the array speaker directive property curve after in ° scope of-90 °～θ～90, optimizing is shown in the dotted line among Fig. 1.

The present invention; Can be according to the power coefficient of optimizing; Obtain the array speaker directive property curve after the optimization under the different frequency, thereby whether the initial selected optimization initial frequency 6000HZ of checking is optimum frequency, and then confirms that the power coefficient of optimizing is optimal selection.

As shown in Figure 2, when solid line is 2250HZ, be not optimized the array speaker directive property curve of processing.According to the optimization coefficient of frequency of above-mentioned execution mode, when frequency was 2250HZ, the array speaker directive property curve after the optimization was shown in dotted line.

As shown in Figure 3, when solid line is 3000HZ, be not optimized the array speaker directive property curve of processing.According to the optimization coefficient of frequency of above-mentioned execution mode, when frequency was 3000HZ, the array speaker directive property curve after the optimization was shown in dotted line.

As shown in Figure 4, when solid line is 4500HZ, be not optimized the array speaker directive property curve of processing.According to the optimization coefficient of frequency of above-mentioned execution mode, when frequency was 4500HZ, the array speaker directive property curve after the optimization was shown in dotted line.

As shown in Figure 5, when solid line is 10000Hz, be not optimized the array speaker directive property curve of processing.According to the optimization coefficient of frequency of above-mentioned execution mode, when frequency was 10000Hz, the array speaker directive property curve after the optimization was shown in dotted line.

As shown in Figure 6, when solid line is 15000Hz, be not optimized the array speaker directive property curve of processing.According to the optimization coefficient of frequency of above-mentioned execution mode, when frequency was 15000Hz, the array speaker directive property curve after the optimization was shown in dotted line.

Extremely shown in Figure 6 like Fig. 1; Optimizing centering high band directive property through power coefficient strengthens especially obvious; Medium-high frequency section secondary lobe can reduce 15-20dB than the array speaker that is not optimized processing; Acoustic irradiation master energy is controlled in the positive and negative 40 degree left and right sides scopes of level, effectively improves the directive property of system.In addition, based on the array speaker directive property curve of Fig. 1 to the optimization shown in Figure 6, the power coefficient that can confirm the optimization that this embodiment is tried to achieve is optimal selection.

Above-described only is execution mode of the present invention, should be pointed out that for the person of ordinary skill of the art at this, under the prerequisite that does not break away from the invention design, can also make improvement, but these all belongs to protection scope of the present invention.

Claims (3)

1. a directivity optimization method of array loudspeaker, is characterized in that: the method comprises the steps: Step S001: Provide an array speaker with n speaker units evenly distributed on a straight line, so that the distance between two adjacent speaker units is l, and the total length of the array speaker is L=(n-1)×l; Step S002: Provide a test point p, so that the distance from the center point of the array speaker is r, and the horizontal angle with the center point of the array speaker is θ, and the distances between each speaker unit and the test point p are r ₁ , r ₂ …r _n ; Calculate the reference sound pressure of the speaker unit at the test point p, θ=0° and the synthetic total sound pressure of the speaker unit at the test point p

Among them, f is the signal frequency, c is the sound velocity, rn is the signal delay time, pn is the signal phase, wn is the loudspeaker point source strength, k is the wave number, d is the loudspeaker unit diameter, and the directivity optimization method of the array loudspeaker selects tn=0 , pn=0; finally determine the vertical directivity function of the array loudspeaker, by changing the point source strength wn of the loudspeaker, combined with the output result of the vertical directivity of the array loudspeaker, determine a group of optimized vertical directivity of the array loudspeaker, according to the point source of the loudspeaker The source intensity wn obtains the power matching coefficient Wn=wn ² ; Step S003: setting the optimization conditions of the directivity optimization method of the array loudspeaker, so as to obtain the optimized power coefficient; Wherein in step S003, the optimization conditions of the directivity optimization method of the array loudspeaker include: Step K001: set optimization order, delay time, signal phase, loudspeaker point source strength, and provide a comparison module; Step K002: Set the point source intensity of the first group of loudspeakers, determine the first group of power coefficients, and obtain the directivity curve of the array loudspeakers under the first group of power coefficients in the range of -90° ~ θ ~ 90°, starting from the first Find the directivity value when θ=0° from the array loudspeaker directivity curve of the group power coefficient, that is, the first reference directivity value and use the comparison module to find out the directivity value between -90°～θ～-45° and 45°～θ The maximum value of directivity within the range of ~90°, that is, the first directivity value, and calculate the first directivity difference; Step K003: Set the point source strength of the second group of loudspeakers, determine the second group of power coefficients, and obtain the directivity curve of the array loudspeakers under the second group of power coefficients in the range of -90°～θ～90°, from the second Find the directivity value when θ=0° from the array loudspeaker directivity curve of the group power coefficient, that is, the second reference directivity value and use the comparison module to find out the directivity value between -90°～θ～-45° and 45°～θ The maximum value of the directivity within the range of ~90°, that is, the second directivity value, calculates the second directivity difference; and so on, set the point source strength of the N ^nth group of speakers, determine the N ^nth group power coefficient, and get The directivity curve of the array loudspeaker under the power coefficient of the ^{N nth} group, find out the directivity value when θ=0° from the directivity curve of the array loudspeaker under the power coefficient of the N nth group, that is, the N ^nth reference directivity value and Use the comparison module to find the maximum value of directivity in the ranges of -90°～θ～-45° and 45°～θ～90°, that is, the N ^nth directivity value, and calculate the N ^nth directivity difference; Step K004: Use the comparison module to find the maximum value from the first directivity difference to the ^Nth directivity difference, so as to determine the power coefficient corresponding to the maximum value, that is, the optimized power coefficient. 2. the directivity optimization method of array loudspeaker according to claim 1, is characterized in that: the directivity optimization method of described array loudspeaker also comprises according to optimized power coefficient, obtains the array loudspeaker directivity after optimization under different frequencies curve, so as to verify whether the initially selected optimized starting frequency is the optimal frequency, and then determine that the optimized power coefficient is the best choice. 3. the directivity optimization method of array loudspeaker according to claim 2, is characterized in that: the

is the directivity function of a single loudspeaker unit.

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