CN1296372A - Audio frequency processing circuit - Google Patents
Audio frequency processing circuit Download PDFInfo
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- CN1296372A CN1296372A CN 99117222 CN99117222A CN1296372A CN 1296372 A CN1296372 A CN 1296372A CN 99117222 CN99117222 CN 99117222 CN 99117222 A CN99117222 A CN 99117222A CN 1296372 A CN1296372 A CN 1296372A
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Abstract
The present invention discloses a voice-frequency processing circuit, which consists of sound field expanding circuit, after-circulating sound processing circuit and low-pass filter circuit, in which the input ends of left and right sound channel signals of L and R of sound field expanding circuit are connected with the output ends of two sound channels of VCD, DVD player and computer sound card. It has the front left and right sound channel signal output end, middle sound channel output signal SC output end, after-circulating sound signal SUR output end and heavy low-voice signal SB output end, the signal is amplified, then transferred to correspondent loudspeakers SP1-SP6 and played back so as to obtain artificial three-dimensional surround stereo effect. The family cinema consisting of said processing circuit is low in cost.
Description
The present invention is an audio frequency processing circuit, belongs to the improvement technology of circuit in the sound equipment field.
The market of home theater is in rapid rise at present, acoustic image software is the CD laser disc for example, with stereo more, the laser disc that a plurality of sound channels are recorded with coding techniques, quantity is also gradually many, recording as the Doby coding techniques, promptly is that also the effect that sound is moved forward and backward has been recorded except recording the effect of sound move left and right.Acoustic image software such as VCD, the DVD laser disc comprises the program of movie theatre effect, substantially all be to record with the Doby coding techniques, but these programs all must authorize and pay the integrated circuit that foreign patent is taken to go decoding with Dolby Labs, increased the cost of playback device greatly, influenced home theater market and popularized.Also popular some kinds of sound field expansion techniques on the market, for example Canadian QSound technology, the Sound Retrieval System technology of U.S. SRS Labs company, be before utilizing about 2 channel loudspeakers sound field is widened, but for using the software that the Doby coding techniques is recorded, the effect that moves forward and backward is obviously inenough; Then effect is enough dissatisfied and the Doby decoding technique is for the software of playing normal stereo.
The object of the present invention is to provide the stronger audio frequency processing circuit of a kind of compatibility, used the sound equipment of this circuit, can be separated into 4～6 road signals to dual track and reappear surrounding sound effect through dolby pro logic or AC-3 coding; More important is the surround sound effect that can be extended to the sound field of any two sound channel sound source a plurality of sound channels; So just can reach and adapt to various recording softwares with not high cost.
Purpose of the present invention can reach by following technical solution:
A kind of audio frequency processing circuit, include sound field expanded circuit (1), back surround sound treatment circuit (2), low-pass filter circuit (3), the left and right sound track signals L of sound field expanded circuit (1) wherein, the R input is the input of treatment circuit, connect the VCD machine, radio tuner, the output of two sound channel sound source such as computer sound card, its left and right sound track signals L ', R ' output is the preceding left and right sound track signals output of treatment circuit, its left and right acoustic channels difference signal (R-L) output is connected with the input of back surround sound treatment circuit (2), and its left and right acoustic channels composite signal R+L output is a center channels output signal SC output, and composite signal R+L output also connects the input of low-pass filter circuit (3); Wherein the output of back surround sound treatment circuit (2) is the back surround sound signal SUR of treatment circuit, the SUL output, wherein the output of low-pass filter circuit (3) is the supper bass signal SB output of treatment circuit, the output of treatment circuit is connected respectively to the input of 6 channel audio power amplification circuits, promotes the loud speaker of corresponding sound channel.
The preceding left and right acoustic channels output signal L ' of treatment circuit, R ' are respectively by preceding left and right acoustic channels audio power amplifying circuit (4), and (5) promote preceding left and right acoustic channels loud speaker SP1, SP2; The back right and left rings of treatment circuit is around acoustic output signal SUL, and by surround channel audio power amplifying circuit (7) after 2, (9) promote the back right and left rings around channel loudspeaker SP4, SP5 to SUR respectively; The supper bass output signal SB of the low-pass filter circuit of treatment circuit (3) promotes subwoofer SP3 by supper bass power amplification circuit (6); When arranging center channels loud speaker SP6 is arranged, the center channels signal SC output of treatment circuit promotes center channels loud speaker SP6 by center channels audio power amplifying circuit (8).
Sound field expanded circuit (1) includes the follow circuit b1 that operational amplifier constitutes, b2, the subtracter h1 that operational amplifier constitutes, the negative circuit g2 that operational amplifier constitutes, the add circuit g1 that operational amplifier constitutes, g3, g4 and frequency compensation network F1, and doubly-linked potentiometer VRmn, the left and right acoustic channels L of described sound field expanded circuit (1), the R signal input part is the input of follow circuit b2 and b1, b2 output signal L and b1 output signal R; The output of b2 and b1 is connected to the input of subtraction circuit h1 simultaneously, h1 output R-L signal, the output of h 1 is its left and right acoustic channels difference signal (R-L) output, the output of h1 also connects the input of frequency compensation network F1, frequency compensation network F1 output f (R-L) signal, the output of F1 connects the input of negative circuit g2 and the input of g4 by the wherein VRm of company of doubly-linked potentiometer VRmn, this f (R-L) signal becomes mf (R-L) signal through the adjusting of potentiometer VRm, transfer to the input of negative circuit g2 again, negative circuit g2 exports mf (L-R), and the output of negative circuit g2 connects the input of g3; B2, the output of b1 is connected to add circuit g1 input simultaneously, g1 output R+L signal, the g1 output is the left and right acoustic channels composite signal R+L output of described sound field expanded circuit (1), the g1 output also connects VRn by other one of potentiometer and connects g4, the input of g3, this R+L signal becomes n (R+L) signal through the adjusting of potentiometer VRn; The b1 output connects the input of g4, so R signal of b1 output, F1 is through mf (R-L) signal of VRm output, be input to the input of g4 simultaneously through n (R+L) signal of VRn output with g1, g4 exports R+mf (R-L)+n (R+L) signal, and therefore the R channel output end signal R ' of described sound field expanded circuit (1) is R+mf (R-L)+n (R+L); In addition, the b2 output connects the input of g3, so L signal of b2 output, mf (L-R) signal of negative circuit g2 output, be input to the input of g3 simultaneously through n (R+L) signal of VRn output with g1, g3 exports L+mf (L-R)+n (R+L) signal, and therefore the L channel output end signal L ' of described sound field expanded circuit (1) is L+mf (L-R)+n (R+L).
Back surround sound treatment circuit (2) includes the follow circuit d1 that operational amplifier constitutes, d2 and negative circuit d3, low pass filter F2, F3 and delay circuit Y1, wherein the input of d1 is connected with left and right acoustic channels difference signal (R-L) output of sound field expanded circuit (1), the output of d1 is connected with the input of low pass filter F2, the output of F2 is connected with the input of delay circuit Y1, the output of Y1 is connected with the input of low pass filter F3, the output of F3 connects the input of follow circuit d2 by the VR2 of potentiometer, the output output of d2 is through (R-L) signal SUR of low-pass filtering and time-delay, the output of d2 connects the input of negative circuit d3, the output output of d3 is through (L-R) signal SUL of low-pass filtering and time-delay, and the output of d2 and the output of d3 are the right surround signal and the left surround signal output of described back surround sound treatment circuit (2).
Include by resistance R 3 in the low-pass filter circuit (3), R4, capacitor C 2, the second order active low-pass filter that C3 and operational amplifier a2 constitute allows the following bass frequencies by 250Hz, low-pass filter circuit (3) output supper bass signal SB.
The sound field expanded circuit (1) that described treatment circuit is included, back surround sound treatment circuit (2), low-pass filter circuit (3) can be arranged in the housing, match as individual components and other stereo sets.
Described treatment circuit is except including sound field expanded circuit (1), back surround sound treatment circuit (2), outside the low-pass filter circuit (3), can also include back surround channel audio power amplifying circuit (7), and with being in the housing, the back surround sound signal SUL output of treatment circuit connects the input of back surround channel audio power amplifying circuit (7), the output of this power amplification circuit (7) connects the outer surround channel loud speaker SP4 of housing, SP5, the wherein anti-phase output that connects to amplifying circuit (7) of SP5; The left and right sound track signals L ' of treatment circuit, R ' output and supper bass signal SB output, and center channels signal SC output connects the input of other outer audio-frequency power amplifier products of housing.
Described treatment circuit is except including sound field expanded circuit (1), back surround sound treatment circuit (2), outside low-pass filter circuit (3) the back surround channel audio power amplifying circuit (7), can also include center channels audio power amplifying circuit (8), and with being in the housing, the back surround sound signal SUL output of treatment circuit connects the input of back surround channel audio power amplifying circuit (7), the output of this power amplification circuit (7) connects the outer surround channel loud speaker SP4 of housing, SP5; The center channels signal SC output of treatment circuit connects the input of center channels audio power amplifying circuit (8), and the output of this power amplification circuit connects the outer center channels loud speaker SP6 of housing; Its left and right sound track signals L ', R ' output are connected the input of other outer audio-frequency power amplifier products of housing with supper bass signal SB output.
Doubly-linked potentiometer VRmn can replace with double-pole switch Km, double-pole switch the 1st group selection contact connects the output of frequency compensation network F1 and the output of add circuit g1 respectively, double-pole switch the 2nd group selection contact ground connection, the double-pole contact of K switch m connects g2 respectively, the input of g4 and g3, the input of g4.When switch pushes the 1st group selection contact, be equivalent to adopt the function of this sound field expanded circuit.
Description of drawings is as follows
The application principle block diagram of Fig. 1 audio frequency processing circuit of the present invention.
The main line schematic diagram of Fig. 2 audio frequency processing circuit of the present invention.
The invention will be further described below in conjunction with drawings and Examples:
Fig. 1 is the application principle block diagram: a kind of audio frequency processing circuit includes sound field expanded circuit (1), back surround sound treatment circuit (2), low-pass filter circuit (3), the left and right sound track signals L of sound field expanded circuit (1) wherein, the R input is the input of treatment circuit, be connected CD by total volume control potentiometer VR1 with selector switch (KA), VCD, DVD player, radio tuner, recorder, the output of two sound channel sound source such as computer sound card, its left and right sound track signals L ', R ' output is the preceding left and right sound track signals output of treatment circuit, left and right acoustic channels audio power amplifying circuit (4) before connecting respectively, (5) input, its left and right acoustic channels difference signal (R-L) output is connected with the input of back surround sound treatment circuit (2), its left and right acoustic channels composite signal R+L output is a center channels output signal SC output, by the input of volume control potentiometer VR4 connection center channels audio power amplifying circuit (8), composite signal R+L output also connects the input of low-pass filter circuit (3); Wherein the output of back surround sound treatment circuit (2) is the back surround sound signal SUR of treatment circuit, and the SUL output connects back surround channel audio power amplifying circuit (7), the input of (9); Wherein the output of low-pass filter circuit (3) is the supper bass signal SB output of treatment circuit, regulates the input that volume connects supper bass power amplification circuit (6) by volume control potentiometer VR3.
The output of treatment circuit is connected to the input of 6 channel audio power amplification circuits, promote the loud speaker of corresponding sound channel: the preceding left and right sound track signals L ' of treatment circuit, R ' output connects preceding left and right acoustic channels audio power amplifying circuit (4) respectively, (5) input, left and right acoustic channels loud speaker SP1 before the output of this power amplification circuit connects, SP2 can obtain the effect that sound field is expanded; The back left and right sides surround sound signal SUL of treatment circuit, surround channel audio power amplifying circuit (7) after the SUR output connects 2, the input of (9), the output of this power amplification circuit connect the back right and left rings around channel loudspeaker SP4, SP5 makes and listens the hearer and feel and surrounded by sound field; The supper bass signal SB output of the low-pass filter circuit of treatment circuit (3) is regulated the input that volume connects supper bass power amplification circuit (6) by volume control potentiometer VR3, the output of this power amplification circuit connects subwoofer SP3, and its effect is to strengthen bass effect; When arranging center channels loud speaker SP6 is arranged, the center channels signal SC output of treatment circuit is by the input of volume control potentiometer VR4 connection center channels audio power amplifying circuit (8), and the output of this power amplification circuit connects center channels loud speaker SP6.
Fig. 2 is a treatment circuit main line schematic diagram:
Sound field expanded circuit (1) includes the follow circuit b1 that operational amplifier constitutes, b2, the subtracter h1 that operational amplifier constitutes, the negative circuit g2 that operational amplifier constitutes, the add circuit g1 that operational amplifier constitutes, g3, g4 and frequency compensation network F1, and doubly-linked potentiometer VRmn, the left and right acoustic channels L of described sound field expanded circuit (1), the R signal input part is the input of follow circuit b2 and b1, b2 output signal L and b1 output signal R; The output of b2 and b1 is connected to the input of subtraction circuit h1 simultaneously, h1 output R-L signal, the output of h1 is its left and right acoustic channels difference signal (R-L) output, the output of h1 also connects the input of frequency compensation network F1, frequency compensation network F1 output f (R-L) signal, the output of F1 connects the input of negative circuit g2 and the input of g4 by the wherein VRm of company of doubly-linked potentiometer VRmn, this f (R-L) signal becomes mf (R-L) signal through the adjusting of potentiometer VRm, transfer to the input of negative circuit g2 again, negative circuit g2 exports mf (L-R), and the output of negative circuit g2 connects the input of g3; B2, the output of b1 is connected to add circuit g1 input simultaneously, g1 output R+L signal, the g1 output is the left and right acoustic channels composite signal R+L output of described sound field expanded circuit (1), the g1 output also connects VRn by other one of potentiometer and connects g4, the input of g3, this R+L signal becomes n (R+L) signal through the adjusting of potentiometer VRn; The b1 output connects the input of g4, so R signal of b1 output, F1 is through mf (R-L) signal of VRm output, be input to the input of g4 simultaneously through n (R+L) signal of VRn output with g1, g4 exports R+mf (R-L)+n (R+L) signal, and therefore the R channel output end signal R ' of described sound field expanded circuit (1) is R+mf (R-L)+n (R+L); In addition, the b2 output connects the input of g3, so L signal of b2 output, mf (L-R) signal of negative circuit g2 output, be input to the input of g3 simultaneously through n (R+L) signal of VRn output with g1, g3 exports L+mf (L-R)+n (R+L) signal, and therefore the L channel output end signal L ' of described sound field expanded circuit (1) is L+mf (L-R)+n (R+L).
The sound of singer in the program, dialogue sound, its left and right sides signal is equal substantially, and acoustic image is positioned in the middle of the place ahead, applauds and background sound, and its left and right sides signal is change at random, so its (R-L) comprised these around signal.
Know, by stereosonic law of sines sin a=[(L-R)/(L+R)] the sin b formula of deriving the expansion of relevant acoustic image is sin a ＂=[(1+k)/(1-k)] sin a, wherein b is that preceding left and right acoustic channels loud speaker is to the half angle of listening the hearer, for example the distance between the left and right acoustic channels loud speaker is 2 meters, listen the hearer and all be 2 meters respectively to the distance between the loud speaker, be equilateral triangle, interior angle is 60 degree, then b=30 degree angles; L and R are respectively left and right sound track signals intensity, a is the acoustic image positions azimuth that is drawn by the stereosonic law of sines by signal strength signal intensity L and R, k is that sound channel has added the composition ratio of another sound channel inversion signal therein, and a ＂ listens the acoustic image positions azimuth that the hearer feels.For example: R ＂=(R-kL), when 0＜K＜1, [(1+k)/(1-k)]＞1 in the above-mentioned acoustic image extends equation, thus a ＂＞a, thereby the acoustic image that is drawn by R ＂ has been expanded.
Left and right acoustic channels R and L add respectively (R-L) and (L-R) after, be equivalent to R ＂=(R-kL) and L ＂=(L-kR), the people is felt before the position of left and right acoustic channels loud speaker widened.Because human head and ear are to the barrier effect of sound wave, frequency is revised through frequency compensation network F1, and the azimuth that frequency spectrum medium-high frequency component is provided is consistent with the azimuth that low frequency component provides, and the acoustic image after avoiding sound field to widen is fuzzy.The frequency compensation network F1 here is made up of the RC filter network, makes that 700Hz frequency following and more than the 7KHz is relative to be compensated lifting.
Test is learnt, after left and right acoustic channels R and L add f (R-L) and f (L-R) respectively, the position of left and right acoustic channels loud speaker had been widened before the people was felt, but, light has only these compositions, and sound is more discrete, and the sensation of wafing is arranged, after adding the composition of (R+L) again, sensuously drawn again from distance far away.Test and digital proof, current left and right acoustic channels loud speaker is put along with loud speaker and after definite, m and n each have an optimum value to the half angle b that listens the hearer, this moment, sound field both was expanded, sound do not waft again from, very steady and sure, for example make and listen the hearer and feel that the sound of sea wave in the music directly gets to both sides by the side of.If m=m ' y1, n=n ' y2, y1 wherein, y2 is the gain coefficient in the relevant circuit, is fixed on optimum value, m ' and n ' are the variable quantity of doubly-linked potentiometer VRmn, m ' and n ' change between 0-1, and when m ' and n ' changed degree of expansion according to m '=n ' variation, it is clear that acoustic image positions still keeps, VRm and VRn adjusted in concert are changed to keep m '=n ', so adopt doubly-linked potentiometer VRmn in the circuit.
Potentiometer VRmn is the degree of regulating the sound field expansion, and when m '=n '=1, sound field obtains largest extension.On some application scenario, m '=n ' gets it and equals zero or 1 just passable, so wherein doubly-linked potentiometer VRmn also can replace with double-pole switch Km, double-pole switch the 1st group selection contact connects the output of frequency compensation network F1 and the output of add circuit g1 respectively, double-pole switch the 2nd group selection contact ground connection, the double-pole contact of K switch m connects g2 respectively, the input of g4 and g3, the input of g4.When switch pushes the 2nd group selection contact ground connection, when being equivalent to m '=n '=0 retaining, R '=R and L '=L promptly is the function that does not adopt this sound field expanded circuit; When switch pushes the 1st group selection contact, when being equivalent to m '=n '=1 retaining, be equivalent to VRm and VRn is transferred to maximum, promptly be the function that has adopted this sound field expanded circuit.
In the present embodiment, back surround sound treatment circuit (2) includes the follow circuit d1 that operational amplifier constitutes, d2 and negative circuit d3, low pass filter F2, F3 and delay circuit Y1, wherein the input of d1 is connected with left and right acoustic channels difference signal (R-L) output of sound field expanded circuit (1), the output of d1 is connected with the input of low pass filter F2, the output of F2 is connected with the input of delay circuit Y1, the output of Y1 is connected with the input of low pass filter F3, the output of F3 connects the input of follow circuit d2 by the VR2 of potentiometer, the output output of d2 is through (R-L) signal SUR of low-pass filtering and time-delay, the output of d2 connects the input of negative circuit d3, the output output of d3 is through (L-R) signal SUL of low-pass filtering and time-delay, and the output of d2 and the output of d3 are the right surround signal and the left surround signal output of described back surround sound treatment circuit (2).
SUR and SUL are through time-delay 20～50ms and following f (R-L) and f (L-R) signal of frequency 7 KHz.The general sound of singing and talking in the middle of all being, promptly the composition in L and R equates, has not just had the composition of these middle voices behind the L-R, remaining musical instrument sound and the ambient sound that distributes; Say again, L channel that the Doby coding techniques is recorded and R channel all contain opposite back around signal of phase place respectively, and behind the L-R, this back has been 2 times of containing of original each sound channel around signal,, make and listen the hearer and feel that the sound of sea wave in the music directly gets to after one's death again from back broadcast through time-delay and low-pass filtering.
Back surround sound treatment circuit (2) also can be arranged like this, increase the subtracter h2 that an operational amplifier constitutes, follow circuit d1 wherein, the input of d2 respectively with sound field expanded circuit (1) in left and right sound track signals L ', R ' output connects, the output of d1, the output of d2 is connected with the input of h2, and h2 exports L '-R ' signal, the input of low pass filter F2 is connected with the output of h2, the output of F2 is connected with the input of delay circuit Y1, and the output of Y1 is connected with the input of F3, and the output output of F3 is through L '-R '=(1+2mf) (L-R) of low-pass filtering and time-delay, it is the SUL signal, pass through negative circuit d3 again, become the SUR signal, through experiment, when m=1, its surrounding effect is more better during than m=0, this and preceding left and right acoustic channels loud speaker SP1, and the sound field of SP2 is expanded relevant.
The general singing and the sound of speech in the middle of all being, especially when the personage of movie program bust shot camera lens talks, the sound in the middle of the speech especially, promptly the composition of Jiang Hua signal in L and R equates, it is 2 times of containing of each sound channel originally that R+L makes the signal of this speech.Distance between the current left and right acoustic channels loud speaker is bigger, the position of listening the hearer is not to face TV, promptly not when the centre position, front of preceding left and right acoustic channels loud speaker, sound of speech can be offset to the left and right with the position of listening the hearer, the signal of R+L play via the locational center channels loud speaker of television set SP6 in the middle of being placed on, can be withdrawn into screen place to the dialogue that has been offset.
Include by resistance R 3 in the low-pass filter circuit (3), R4, capacitor C 2, the second order active low-pass filter that C3 and operational amplifier a2 constitute allows the following bass frequencies by 250Hz, low-pass filter circuit (3) output supper bass signal SB.Present embodiment circuit (3) is to include operational amplifier a1, a2 and peripheral resistance R 1-R4, capacitor C 1-C4, wherein an end of capacitor C 1 is the input of this low-pass filter circuit (3), be connected with the output of g1 in the sound field expanded circuit (1), the other end of C1 is connected with the input of a1 by resistance R 2, the output of a1 is by resistance R 3, R4 connects the input of a2, resistance R 3, R4, capacitor C 2, C3 and operational amplifier a2 constitute the second order active low-pass filter, and the output of a2 is the output of low-pass filter circuit (3).
The sound field expanded circuit (1) that described treatment circuit is included, back surround sound treatment circuit (2), low-pass filter circuit (3) can be arranged in the housing, match as individual components and other stereo sets.When described treatment circuit is packaged into an integrated circuit, potentiometer VRmn, VR2 and relevant resistance, electric capacity can be connected with internal circuit by the pin by integrated circuit outside integrated circuit.
Described treatment circuit is except including sound field expanded circuit (1), back surround sound treatment circuit (2), outside the low-pass filter circuit (3), can also include back surround channel audio power amplifying circuit (7), and with being in the housing, the back surround sound signal SUL output of treatment circuit connects the input of back surround channel audio power amplifying circuit (7), and the output of this power amplification circuit (7) connects the outer surround channel loud speaker SP4 of housing, SP5; The left and right sound track signals L ' of treatment circuit, R ' output and supper bass signal SB output, and center channels signal SC output connects the input of other outer audio-frequency power amplifier products of housing.
Because SUL and SUR signal phase differ 180 degree, therefore the input of surround channel audio power amplifying circuit (7) after can connecting 1 by the SUL output, the output of this power amplification circuit connects the back right and left rings around channel loudspeaker SP4, SP5, the wherein anti-phase output that connects to amplifying circuit (7) of SP5.When described treatment circuit is packaged into an integrated circuit, potentiometer VRmn, VR2 and relevant resistance, electric capacity can be connected with internal circuit by the pin by integrated circuit outside integrated circuit.
Described treatment circuit is except including sound field expanded circuit (1), back surround sound treatment circuit (2), outside low-pass filter circuit (3) the back surround channel audio power amplifying circuit (7), can also include center channels audio power amplifying circuit (8), and with being in the housing, the back surround sound signal SUL output of treatment circuit connects the input of back surround channel audio power amplifying circuit (7), the output of this power amplification circuit (7) connects the outer surround channel loud speaker SP4 of housing, SP5; The center channels signal SC output of treatment circuit connects the input of center channels audio power amplifying circuit (8), and the output of this power amplification circuit connects the outer center channels loud speaker SP6 of housing; Its left and right sound track signals L ', R ' output are connected the input of other outer audio-frequency power amplifier products of housing with supper bass signal SB output.Described treatment circuit includes sound field expanded circuit (1), back surround sound treatment circuit (2), low-pass filter circuit (3) and back surround channel audio power amplifying circuit (7) and center channels audio power amplifying circuit (8) can be packaged into an integrated circuit or thick film integrated circuit, potentiometer VRmn, VR2 and relevant resistance, electric capacity can be connected with internal circuit by the pin by integrated circuit outside integrated circuit; Also can be arranged in the casing, become a product and other preceding left and right acoustic channels audio-frequency power amplifiers and speaker products and match together with transformer.
The audio amplifier position arrangement of loud speaker is such, and the audio amplifier of preceding right channel loudspeaker SP2 is in the right front of listening the hearer.The audio amplifier of preceding left channel loudspeaker SP1 is in the left front of listening the hearer.The audio amplifier of subwoofer SP3 can be placed on Anywhere, the audio amplifier of center channels loud speaker SP6, generally be with the television indicator screen together, be located in the middle of the place ahead of listening the hearer.Surround channel loud speaker SP4, the audio amplifier of SP5 should be arranged in the rear, the ear left and right sides of listening the hearer, and it is better to be higher than ear.
It when the present invention uses input treatment circuit, be connected CD by potentiometer VR1 with selector switch (KA), VCD, DVD player, radio tuner, the output of two sound channel sound source such as deck, the input of each channel audio power amplification circuit is the output of connection processing circuit respectively, and signal is play through transporting to corresponding loud speaker SP1～SP6 after amplifying.During adjusting, potentiometer VRm and VRn accent are pushed the function that adopts this sound field expanded circuit (1) in maximum or K switch m; It is below half of preceding left and right acoustic channels volume that back surround channel volume is transferred to; The effect of the center channels of this treatment circuit is that the dialogue in the film is positioned at screen place, perhaps talks with hour ability usefulness of sound at the film of indivedual softwares, at ordinary times, if the space is little in the hall, when especially playing common stereo music, does not need to use; Supper bass can be liked regulating according to the individual, at this moment can well be simulated surrounding stereophonic field effect.Use audio frequency processing circuit of the present invention, can connect the output of various dual track sources of sound, with low cost by the home theater that this treatment circuit is formed, popularize popular easily.
Claims (8)
1. audio frequency processing circuit, include sound field expanded circuit (1), back surround sound treatment circuit (2), low-pass filter circuit (3), it is characterized in that the wherein left and right sound track signals L of sound field expanded circuit (1), the R input is the input of treatment circuit, connect the output of two sound channel sound source such as VCD machine, its left and right sound track signals L ', R ' output is the preceding left and right sound track signals output of treatment circuit, its left and right acoustic channels difference signal (R-L) output is connected with the input of back surround sound treatment circuit (2), its left and right acoustic channels composite signal R+L output is a center channels output signal SC output, and composite signal R+L output also connects the input of low-pass filter circuit (3); Wherein the output of back surround sound treatment circuit (2) is the back surround sound signal SUR of treatment circuit, the SUL output, wherein the output of low-pass filter circuit (3) is the supper bass signal SB output of treatment circuit, the output of treatment circuit is connected respectively to the input of 6 channel audio power amplification circuits, promotes the loud speaker of corresponding sound channel.
2. audio frequency processing circuit according to claim 1, it is characterized in that sound field expanded circuit (1) includes the follow circuit b1 that operational amplifier constitutes, b2, the subtracter h1 that operational amplifier constitutes, the negative circuit g2 that operational amplifier constitutes, the add circuit g1 that operational amplifier constitutes, g3, g4 and frequency compensation network F1, and doubly-linked potentiometer VRmn, the left and right acoustic channels L of described sound field expanded circuit (1), R signal input part are the inputs of follow circuit b2 and b1, b2 output signal L and b1 output signal R; The output of b2 and b1 is connected to the input of subtraction circuit h1 simultaneously, h1 output R-L signal, the output of h1 is its left and right acoustic channels difference signal (R-L) output, the output of h1 also connects the input of frequency compensation network F1, frequency compensation network F1 output f (R-L) signal, the output of F1 connects the input of negative circuit g2 and the input of g4 by the wherein VRm of company of doubly-linked potentiometer VRmn, this f (R-L) signal becomes mf (R-L) signal through the adjusting of potentiometer VRm, transfer to the input of negative circuit g2 again, negative circuit g2 exports mf (L-R), and the output of negative circuit g2 connects the input of g3; B2, the output of b1 is connected to add circuit g1 input simultaneously, g1 output R+L signal, the g1 output is the left and right acoustic channels composite signal R+L output of described sound field expanded circuit (1), the g1 output also connects VRn by other one of potentiometer and connects g4, the input of g3, this R+L signal becomes n (R+L) signal through the adjusting of potentiometer VRn; The b1 output connects the input of g4, so R signal of b1 output, F1 is through mf (R-L) signal of VRm output, be input to the input of g4 simultaneously through n (R+L) signal of VRn output with g1, g4 exports R+mf (R-L)+n (R+L) signal, and therefore the R channel output end signal R ' of described sound field expanded circuit (1) is R+mf (R-L)+n (R+L); In addition, the b2 output connects the input of g3, so L signal of b2 output, mf (L-R) signal of negative circuit g2 output, be input to the input of g3 simultaneously through n (R+L) signal of VRn output with g1, g3 exports L+mf (L-R)+n (R+L) signal, and therefore the L channel output end signal L ' of described sound field expanded circuit (1) is L+mf (L-R)+n (R+L).
3. audio frequency processing circuit according to claim 2, it is characterized in that back surround sound reason circuit (2) includes the follow circuit d1 that operational amplifier constitutes, d2 and negative circuit d3, low pass filter F2, F3 and delay circuit Y1, wherein the input of d1 is connected with left and right acoustic channels difference signal (R-L) output of sound field expanded circuit (1), the output of d1 is connected with the input of low pass filter F2, the output of F2 is connected with the input of delay circuit Y1, the output of Y1 is connected with the input of low pass filter F3, the output of F3 connects the input of follow circuit d2 by the VR2 of potentiometer, the output output of d2 is through (R-L) signal SUR of low-pass filtering and time-delay, the output of d2 connects the input of negative circuit d3, the output output of d3 is through (L-R) signal SUL of low-pass filtering and time-delay, and the output of d2 and the output of d3 are the right surround signal and the left surround signal output of described back surround sound treatment circuit (2).
4. Audio Processing according to claim 1, it is characterized in that including by resistance R 3 in the low-pass filter circuit (3), R4, capacitor C 2, the second order active low-pass filter that C3 and operational amplifier a2 constitute, allow following bass frequencies, low-pass filter circuit (3) output supper bass signal SB by 250Hz.
5. audio frequency processing circuit according to claim 1, it is characterized in that the sound field expanded circuit (1) that described treatment circuit is included, back surround sound treatment circuit (2), low-pass filter circuit (3) can be arranged in the housing, match as individual components and other stereo sets.
6. according to claim 1, the described audio frequency processing circuit of claim 5, it is characterized in that described treatment circuit except including sound field expanded circuit (1), back surround sound treatment circuit (2), outside the low-pass filter circuit (3), can also include back surround channel audio power amplifying circuit (7), and with being in the housing, the back surround sound signal SUL output of treatment circuit connects the input of back surround channel audio power amplifying circuit (7), the output of this power amplification circuit (7) connects the outer surround channel loud speaker SP4 of housing, SP5; The left and right sound track signals L ' of treatment circuit, R ' output and supper bass signal SB output, and center channels signal SC output connects the input of other outer audio-frequency power amplifier products of housing.
7. according to claim 1, claim 5 and 6 described audio frequency processing circuits, it is characterized in that described treatment circuit except including sound field expanded circuit (1), back surround sound treatment circuit (2), outside low-pass filter circuit (3) the back surround channel audio power amplifying circuit (7), can also include center channels audio power amplifying circuit (8), and with being in the housing, the back surround sound signal SUL output of treatment circuit connects the input of back surround channel audio power amplifying circuit (7), the output of this power amplification circuit (7) connects the outer surround channel loud speaker SP4 of housing, SP5; The center channels signal SC output of treatment circuit connects the input of center channels audio power amplifying circuit (8), and the output of this power amplification circuit connects the outer center channels loud speaker SP6 of housing; Its left and right sound track signals L ', R ' output are connected the input of other outer audio-frequency power amplifier products of housing with supper bass signal SB output.
8. according to claim 1 and 2 described audio frequency processing circuits, it is characterized in that wherein doubly-linked potentiometer VRmn can replace with double-pole switch Km, double-pole switch the 1st group selection contact connects the output of frequency compensation network F1 and the output of add circuit g1 respectively, double-pole switch the 2nd group selection contact ground connection, the double-pole contact of K switch m connects g2 respectively, the input of g4 and g3, the input of g4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99117222 CN1296372A (en) | 1999-11-16 | 1999-11-16 | Audio frequency processing circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99117222 CN1296372A (en) | 1999-11-16 | 1999-11-16 | Audio frequency processing circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1296372A true CN1296372A (en) | 2001-05-23 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 99117222 Pending CN1296372A (en) | 1999-11-16 | 1999-11-16 | Audio frequency processing circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1296372A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106231489A (en) * | 2016-07-25 | 2016-12-14 | 深圳市米尔声学科技发展有限公司 | The treating method and apparatus of audio frequency |
| CN106887223A (en) * | 2017-02-22 | 2017-06-23 | 安徽井利电子有限公司 | A kind of musical instrument loudspeaker remote intelligent control system |
| CN114363793A (en) * | 2022-01-12 | 2022-04-15 | 厦门市思芯微科技有限公司 | System and method for converting dual-channel audio into virtual surround 5.1-channel audio |
-
1999
- 1999-11-16 CN CN 99117222 patent/CN1296372A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106231489A (en) * | 2016-07-25 | 2016-12-14 | 深圳市米尔声学科技发展有限公司 | The treating method and apparatus of audio frequency |
| CN106887223A (en) * | 2017-02-22 | 2017-06-23 | 安徽井利电子有限公司 | A kind of musical instrument loudspeaker remote intelligent control system |
| CN114363793A (en) * | 2022-01-12 | 2022-04-15 | 厦门市思芯微科技有限公司 | System and method for converting dual-channel audio into virtual surround 5.1-channel audio |
| CN114363793B (en) * | 2022-01-12 | 2024-06-11 | 厦门市思芯微科技有限公司 | System and method for converting double-channel audio into virtual surrounding 5.1-channel audio |
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