CN101213869A - Level dependent bass management - Google Patents
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- CN101213869A CN101213869A CNA2006800239321A CN200680023932A CN101213869A CN 101213869 A CN101213869 A CN 101213869A CN A2006800239321 A CNA2006800239321 A CN A2006800239321A CN 200680023932 A CN200680023932 A CN 200680023932A CN 101213869 A CN101213869 A CN 101213869A
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Abstract
A signal processing system includes a level dependent bass management system. The level dependent bass management system utilizes audio input signal level information to apply at least one of multiple, available bass management solutions to generate one or more output signals from the audio input signal. In at least one embodiment, initially the level dependent bass management system boosts components of the audio input signal in the low frequency range by an amount sufficient to at least partially compensate for low frequency attenuation of the first speaker without exceeding one or more acceptable limitations of the signal processing system. If boosting alone cannot completely compensate for low frequency attenuation of the first speaker without exceeding one or more acceptable limitations of the signal processing system, the level dependent bass management system processes the audio input signal using an alternate low frequency management solution.
Description
The cross reference of related application
It is the rights and interests of 35 U.S.C. § 119 (e) of the 60/695th, No. 731 U.S. Provisional Application of " bass management that level is correlated with " that the application requires based on the title of submitting on June 30th, 2005.The 60/695th, 731 provisional application comprises exemplary system and method, and it is all in conjunction with therewith as a reference.
Technical field
The present invention relates generally to field of information processing, relates more specifically to be used to provide the system and method for the relevant management of the level of bass signal.
Background technology
Fig. 1 has described example " imperfect " loud speaker and amplitude-frequency response 100 " ideal " loud speaker.The frequency response line 102 of " ideal " loud speaker (" loud speaker ") has the flat frequency response of leap human auditory's (acceptable substantially for from 20Hz to 20kHz) gamut.The frequency response of a few high-end speakers is near the target that obtains flat frequency response 102.But low side to the frequency response of the loud speaker of middle-end does not have near desirable flat response.Comprise that all low sides to the frequency response of the loud speaker of most of reality of the loud speaker of middle-end has departed from flat response in several frequency ranges of human auditory's scope.Frequency response curve 104 has been represented the frequency response of an example (non-ideal speaker).Ideal flat frequency response curve 102 the most tangible departed from almost always at low frequency, and this also is just at the right time the easiest human places of realizing the frequency response of non-flat forms, decay.Most users consciously or the quality of subconsciously estimating loud speaker based on the loudness and the definition of the output of low frequency audio frequency.Louder, the general evaluation of low frequency (" bass ") response more clearly is the loud speaker of sensation " better ".Therefore, the solution of a kind of LF-response of compensate for attenuation (shown in frequency response curve 104) is to improve the gain of low frequency to obtain more flat frequency response.For low level (low-level) input signal, raising is feasible option.But the ability that audio system improves the low level frequency reduces along with the increase of incoming signal level.The typical 20dB/decade frequency response meeting that departs from flat response need improve coefficient to turn back to flat response for 10 gain.Therefore, improve high level signal and can surpass maximum available power at an easy rate.In addition, provide high level signal can cause that circuit unit carries out slicing, can cause that digital-to-analog converter carries out slicing, and can physically damage loud speaker.
Real LF-response needs the driver of big costliness usually, and the home audio of general marketplace is driven by low-cost and organoleptic properties (aesthetics).Therefore, more flat frequency response and low-cost these two targets are intrinsic implacable.
The problem of non-flat forms frequency response even more serious in television set (wherein, loud speaker is common even littler more cheap than the most cheap stand-alone loudspeaker).Owing to need effectively shielding to be generally used for big magnet structure in the woofer driver avoiding the making video image distortion, thereby further hindered the cathode-ray television set to obtain more smooth LF-response.
Adopted multiple solution to compensate the intrinsic relatively poor LF-response of non-ideal speaker.A kind of example solution is a fixed frequency bass management system.Fig. 2 has described the audio system 200 with traditional 5:1 speaker configurations.The 5:1 speaker configurations has six (6) the individual independently audio signal channels that are used to drive six loud speakers.The 5:1 speaker configurations comprises left side main loudspeaker 202, right main speakers 204, left satellite loud speaker 206, right side satellite loudspeakers 208, preceding center loudspeaker 210.Except that other features, the 5:1 loudspeaker arrangement makes the audio frequency design engineer sound origination location can be incorporated in the audio track. Main loudspeaker 202 and 204 and preceding center loudspeaker generally big than satellite loudspeakers 206 and 208.Therefore, main loudspeaker 202 and 204 and the LF-response of preceding loud speaker 210 generally more smooth than satellite loudspeakers 206 and 208 at lower bass frequencies place.The 5:1 loudspeaker arrangement also comprises the low frequency equipment (" LFE ") such as subwoofer (subwoofer bass speaker) 212.Subwoofer 212 is designed to have more desirable response in the 20-100Hz frequency range.Because if being positioned at or being lower than the then most of people of 100Hz, frequency can not pick out the position of sounding, so be positioned at or the audio frequency that is lower than 100Hz is considered to nondirectional.Therefore, for the arrangement of 5:1 loud speaker, the position of subwoofer 212 is unessential.
In the setting up procedure of bass management systems 216, selected one or more passing through (cross-over) frequency.Cross-over frequency is a bass management systems 216 with low-frequency audio signal from a loud speaker mixing and/or be routed to the frequency that is more suitable for another loud speaker that low-frequency sound reproduces.Cross-over frequency can be to be used for the grade of listening to of group of some qualifications () fixed value for example, low, standard, height perhaps preferably also can be used as the function of output level and continuous variable.In at least one embodiment, the filter construction of bass management systems 216 and control break filter and do not introduce the interference of not expecting (artifact) (for example, ticktack, thump, zipper noise gets etc.).Current, the bass management in the fixed frequency bass management system 216 is static.That is,, then no longer manage it in case during system's setting, disposed filtering, route, and mixing.No matter be by the artificial executive system setting of user, still by utilize MultEQ such as Yamaha Parametric RoomAcoustic Optimizer (" YPAO "), the Audyssey Labs of Auto Room Tuner (" ART "), the Yamaha of Intelligent Room Calibration (" IRC "), the ADI of Cirrus Logic Inc., and the system of the technology such as AdaptiQ of Bose come automatic executive system setting, this situation all is the same.Cross-over frequency is all fixed for all audio signal levels, and keeps static for signal processing system 214.Because it not all is constant that the frequency response of loud speaker is listened in the grade at all, so this setup is not best.For example, the low-frequency content that can bass management be set to be lower than 100Hz from the left side and right main speakers 202 and 204 be routed to heavy woofer 212.In the grade of listening to of standard, this set may be best, and still along with the increase of volume, less main loudspeaker can begin to make the frequency distortion that is higher than 100Hz.By cross-over frequency being increased to the distortion that 120Hz can prevent this louder volume place, but only being cost in low some loss of directionality of listening to the grade place.
The television signal treatment system has the very little loud speaker that has very little LF-response usually, and it copies (rolling off) frequency up to 200Hz, and does not have subwoofer usually.In these cases, bass management does not comprise any route or mixing, only leaches low-frequency content with the protection loud speaker.Fixing filter frequencies is not desirable, and this is because loud speaker can reproduce lower frequency safely being lower than the higher volume place of listening to grade.
The solution that another kind is used to compensate the intrinsic relatively poor LF-response of non-ideal speaker is psycho-acoustic bass extension (psycho-acoustic bass extension, " PBE ").PBE theory behind is can be by some combinations of the higher frequency harmonics of the low-frequency sound of expectation synthesize and reproducing this harmonic wave rather than reproduction original frequency " cheating " it is believed that they have heard low-frequency sound.Although there be not " material object " so good, the PBE technology surprising effectively.The enforcement of PBE dates back to the low-frequency sound that the wind instrument that utilizes 20Hz and 40Hz before centuries at least in the church substitutes 10Hz.In market, there is several psycho-acoustic bass extension (PBE) algorithm now, for example, at Waves MaxxBass , the Inc.of Santa Ana of the Waves Audio Ltd. that office is arranged of Knoxville, the TN of the SRS Labs of CA and SRS TruBass
TM
Although have bass management, the setting that utilizes the audio system of PBE algorithm is static, and this audio system has fixing cross-over frequency or zone, leaches real low frequency in this cross-over frequency or zone and substitutes with synthetic harmonic wave.For quiet, normal, and loud listen to grade and same problem occurs in the different situation of desirable cross-over frequency.
Summary of the invention
In one embodiment of the invention, a kind of method of relevant (level dependent) bass management of level that provides in signal processing system comprises: receive the audio input signal that is associated with first loud speaker at least, wherein, the signal in this first loud speaker decay low-frequency range.This method also comprises: be no more than the amount of one or more acceptable restrictions of this signal processing system to be enough to compensate the low cut of first loud speaker at least in part, improve the component of the audio input signal in the low-frequency range; And limited under the situation of the low cut of low frequency being brought up to basic compensation first loud speaker in one or more restrictions of the low-frequency level of audio input signal and this signal processing system, utilize candidate's low frequency rwan management solution RWAN to handle this audio input signal.
In another embodiment of the present invention, be used to provide the signal processing system of the relevant bass management of audio input signal level to comprise: input is used to receive the audio input signal that is associated with first loud speaker at least; And the relevant bass frequency management system of level.The bass frequency management system that this level is relevant comprises: level detector, and it is in response to the level of audio input signal; And amplifier.The bass frequency management system that level is relevant also comprises: control logic circuit, be used to make amplifier to be no more than the amount of one or more acceptable restrictions of signal processing system to be enough to compensate the low cut of first loud speaker at least in part, improve the component of the audio input signal in the low-frequency range, and be used for having limited under the situation of the low cut of low frequency being brought up to basic compensation first loud speaker in the low-frequency level of audio input signal and one or more restrictions of signal processing system, make the relevant bass frequency management system of this level utilize candidate's low frequency rwan management solution RWAN to handle this audio input signal.
In yet another embodiment of the present invention, a kind of signal processing system comprises: the bass frequency management system that the audio input signal level is relevant.The bass frequency management system that this level is relevant comprises: input is used to receive the audio input signal that is associated with first audio output device at least; And equalizer.The bass frequency management system that this level is relevant also comprises: control logic circuit, be connected to input, be used for:, equalizer is improved with the frequency response of compensate for attenuation at least in part to the frequency component of audio input signal if (i) audio input signal comprises having and is in or is lower than the frequency component of first level and has frequency component decay, the LF-response district that is positioned at first audio output device; And if (ii) this frequency component has level greater than first level, and one or more restrictions of signal processing system have limited the frequency response of this frequency component being brought up to basic compensate for attenuation, the frequency component of then utilizing the low frequency rwan management solution RWAN that substitutes to come the processing audio input signal.
In yet another embodiment of the present invention, a kind ofly be used to provide the equipment of the relevant bass frequencies management of audio input signal level to comprise: the device that is used to receive the audio input signal that is associated with first loud speaker at least, wherein, the signal in this first loud speaker decay low-frequency range.This equipment also comprises: be used for being no more than to be enough to compensate the low cut of first loud speaker at least in part the amount of one or more acceptable restrictions of this signal processing system, improve the device of the component of the audio input signal in the low-frequency range.This equipment also comprises: be used for having limited under the situation of the low cut of this low frequency being brought up to basic compensation first loud speaker in the low-frequency level of audio input signal and one or more restrictions of this signal processing system, utilize the low frequency rwan management solution RWAN that substitutes to come the processing audio input signal.
Description of drawings
By with reference to the accompanying drawings, for a person skilled in the art, the present invention may be better understood, and make its multiple purpose, feature, and advantage become apparent.Profit is denoted by like references same or analogous element in whole a few width of cloth figure.
Fig. 1 (indicating prior art) has described the amplitude-frequency response of example non-ideal speaker and desirable loud speaker.
Fig. 2 (indicating prior art) has described the audio system with fixed frequency bass management process.
Fig. 3 has described the audio system with the relevant bass management systems of level.
Fig. 4 has described speaker frequency response plot.
Fig. 5 A, Fig. 5 B, and Fig. 5 C (being referred to as " Fig. 5 ") of whole harmonic distortion levels to(for) the loud speaker of multiple frequency and gain have been described.
Fig. 6 has described the relevant bass management systems of level.
Fig. 7 has described the relevant bass management process of level.
Fig. 8 has described the relevant bass management systems of level with directivity and balance maintenance assembly.
Embodiment
A kind of signal processing system comprises the bass management systems that level is relevant.Therefore, substitute bass management systems is combined with having the fixing solution that is used for all audio input signal level, the bass management systems that this level is correlated with utilizes the audio input signal level information to use in a plurality of feasible bass management solutions at least one to generate one or more output signals from this audio input signal.At first, in at least one embodiment, the bass management systems that this level is relevant is no more than the amount of one or more acceptable restrictions of this signal processing system to be enough to compensate the low cut of first loud speaker at least in part, improve the component of the audio input signal in the low-frequency range.Limit and the low cut of full remuneration first loud speaker if improve one or more acceptables that can not be no more than this signal processing system separately, then the bass management systems that this level is relevant utilizes candidate's low frequency rwan management solution RWAN to come the processing audio input signal.
In at least one embodiment, candidate's bass management solution comprises any following combination: (1) by gain adjust carry out equilibrium, (2) with low frequency signal route to have be better than expect loud speaker LF-response loud speaker, reach (3) applied mental acoustical bass expansion algorithm.
The relevant bass management systems of level is used suitable bass management solution based on known (or estimating at least) characteristic of the level of audio input signal and the loud speaker in the audio system.For example, if audio signal comprises expection and supplies with the low frequency component that loud speaker A uses, and loud speaker A has the frequency response range of uneven, the decay that comprises low frequency component, and then the bass management systems that level is relevant determines whether the audio input signal level is low to moderate is enough to that balanced solution is applied to this low frequency component and improves the gain of this low frequency component to realize the flat frequency response.The gain that the bass management systems that this level is relevant can improve this audio input signal is up to the restriction that reaches this audio system.
As mentioned above, the restriction of this audio system comprises: the ability that surpasses one or more audio system components (for example, power supply, digital-to-analog converter, and amplifier).When the restriction that reaches audio system, the bass management systems that this level is relevant can be selected one or more candidates' bass management solution or one or more candidates' bass management solution is combined with the equalization bass management solution.If the level of audio input signal is initial just too high, then this audio system may not have the ability that improves audio input signal at first, and the relevant bass management systems of level is selected from the non-equalization bass management solution at first.
If the gain of increase audio input signal is impossible or is not enough to frequency response non-flat forms, decay of full remuneration loud speaker A, then the bass management systems (for example) that level is relevant is routed to low frequency component one or more other loud speakers with better LF-response, and/or the sound enhancement techniques that the relevant bass management systems of this level can be used such as the PBE algorithm (for example compensates relatively poor woofer performance, low gain and/or unacceptable frequency response), thus the sound quality of this loud speaker strengthened.The bass management systems that this level is relevant attempts to keep this audio input signal level.Therefore, at least one embodiment, no matter the relevant bass management systems of this level is selected which kind of bass management solution of the combination of a plurality of bass management solutions, it is identical that whole level of this low frequency audio input signal preferably all keep.In addition, when low frequency signal was routed to other loud speakers, the bass management systems that this level is relevant attempted to keep directivity and balance.For example, if route left channel low frequency audio frequency input signal component, then the bass management systems that this level is relevant will preferably be routed to this low-frequency signal components another left speaker keeping direction, and supporting (complimentary) right channel low frequency component is routed to right speaker corresponding to left speaker to keep balance.In at least one embodiment, if can not keep directivity, then this left channel and supporting right channel audio input signal all are routed to the loud speaker (such as subwoofer) with smooth LF-response.
Fig. 3 has described the audio system 300 with the relevant bass management systems 302 of level.With by left side main loudspeaker 304, right main speakers 306, left satellite loud speaker 308, right side satellite loudspeakers 310, preceding center loudspeaker 312, and the 5:1 speaker configurations formed of subwoofer 314 dispose audio system 300.In other embodiments, can with such as 7:1 speaker configurations, four (4) speaker configurations (the 5:1 speaker configurations that for example, does not have center loudspeaker or subwoofer) or any other speaker configurations that only have two (2) speaker configurations that are used for left side and the left side of right speaker and right channel dispose audio system 300.
The bass management systems 302 that level is correlated with changes audio input signal based on the level of the audio input signal that is used for one or more loud speakers, obtains better sound with the loud speaker by audio system 300 and reproduces.During the low frequency at the level place within audio input signal comprises the decay part of the frequency response that is in loud speaker, the bass management systems 302 that level is relevant is used the bass management solution, according to this bass management solution audio input signal is handled, and generation output signal, the directivity (sound origination) that this output signal (at least in one embodiment) keeps this audio input signal to expect originally, keep channel balance, the signal output level that keeps this audio input signal to expect originally, and the LF-response of generation substantially flat.
Every kind of bass management solution comprises that all the level based on the audio input signal level suitably generates one or more bass frequencies rwan management solution RWANs with the one or more audio output signals that keep audio input signal content intention.The application that is used for the specific bass management solution of processing audio input signal depends on whether the level of this audio input signal and the frequency component of this audio input signal are within the unacceptable frequency response range of loud speaker.At least in one embodiment, the bass management systems that level is relevant comprises and can use separately or three kinds of different bass management solutions that combination in any is used, that is (1) equilibrium of adjusting by gain,, (2) with low frequency signal route to have be better than expect loud speaker LF-response loud speaker, reach (3) applied mental acoustical bass expansion algorithm.
In at least one embodiment, the bass management systems 302 that level is relevant uses the bass management solution based on the frequency response of audio input signal level and expection loud speaker at least so that distortion minimization, and (if possible) keeps sound origination intention (intent) and sound balance.The bass management systems 302 that level is relevant can also utilize the system gain data of audio system 300 to determine more accurately suitable bass management solution.In addition, the bass management systems 302 that level is relevant can partly make the whole peaks level of the generation of audio output signal based on audio input signal, and/or the relevant bass management systems 302 of level can make the generation of audio output signal based on the signal level that is used for characteristic frequency.
When changing audio input signal, the bass management systems 302 that level is relevant utilizes the frequency response of audio input signal level and loud speaker.With reference to figure 4, typical low side is not smooth to the frequency response that the frequency response curve 400 of the loud speaker of middle-end shows loud speaker in the appreciable audiorange of the whole mankind.Frequency response curve is at 300Hz to 2, and is more smooth basically in the frequency range of 000Hz, and 2,000Hz to 20 has less distortion in the frequency range of 000Hz.In the low-frequency range from 0Hz to 200Hz, the frequency response of loud speaker significantly reduces along with the reduction of frequency.In the low-frequency range from 0Hz to 200Hz, as long as be no more than the restriction of audio system, loud speaker just can utilize (for example) equalizer to improve the level of audio output signal, with the gain of recovering damage.For example, typical low side also is the function of audio output signal level to the audio distortions in the loud speaker of middle-end.Therefore, the amount that the audio distortions limiting gain that level is relevant improves is if there is gain to improve the gain that can be used for recovering damage.In addition, the gain that improves output signal can require than available higher power, perhaps may cause making the assembly of audio system 300 overheated.
With reference to figure 5A, Fig. 5 B, and Fig. 5 C (being referred to as " Fig. 5 "), the total harmonic distortion of loud speaker (total harmonic distortion, " THD ") is the function of the frequency of the function of level of the audio input signal that is associated with this loud speaker and this audio input signal.Fig. 5 has described nine (9) to side by side curve.Curve among Fig. 5 is to be used for same loud speaker as the frequency response curve among Fig. 4.Curve 502 and curve 504 both all show first group 12 (12) harmonic waves being used for loud speaker at ten (10) different output level place the harmonic frequency response for sine wave, they are standardized as the frequency response at the fundamental frequency place of 100Hz.Curve 502 and curve 504 are carried out standardization, so that fundamental frequency response is 0dB.Curve 504 has been described the relation curve of the audio output level of THD percentage and loud speaker.THD be defined as all harmonic waves power and account for all harmonic waves add fundamental (fundamental) power and percentage (that is amplitude-normalized).In formula 1, provided the formula that is used for THD:
Wherein, the harmonic response of N harmonic wave of Hn=, the response of H1=fundamental.504 of curves have been considered the 5th the-the 13rd harmonic wave (H5-H13), to describe the beginning of the distortion that causes owing to the loud speaker overload better.When 100Hz, surpass when output level is increased to from frequency response curve 502 and 504 as can be seen ,-during 18dB, the THD of loud speaker increases and reaches maximum THD at the maximum level place of 0dB.Come all frequency curve 505-520 of key-drawing 5 in the mode identical with curve 502 and 504.Therefore, curve 504-520 represents 250Hz or above place ,-THD of level loud speaker was very low when the output of 3dB loud speaker was following.-more than the 3dB, then cause the speaker performance variation owing to sharply increasing THD.But when frequency drops to when being lower than 250Hz, at lower output level place, loud speaker begins degradation.
Fig. 6 has described an embodiment such as the relevant bass management systems 600 of the level of the relevant bass management systems 302 of level.In at least one embodiment, the bass management systems 600 that level is relevant is worked according to the relevant bass management process 700 of the described level of Fig. 7.The bass management systems 600 that level is relevant comprises: control logic circuit 602 is used to be produced as the control signal that audio system 300 provides the relevant bass management of level.In order to provide appropriate control signals, the frequency response and the distortion profile (distortionprofile) of each loud speaker in operation 702 acquisitions or the detection signal treatment system 316 or the loud speaker of selection.In addition, the data that operation 702 can also obtain or other restrictions of detection and audio system 300 are relevant (for example, available horsepower, be used for such as the assembly of Any Digit-analogue converter slicing (clipping) data, reach temperature limitation).Can be from the information acquisition frequency response of (for example) producer, distortion profile, and operation constraint data, and as storage in audio system 300.In another embodiment, signal processing system 316 detects the loud speaker in the audio systems 300, and the loud speaker that will be subjected to 600 influences of the relevant bass management systems of level to those input signals is at least determined frequency response and distortion profile.Can (for example) when the scheduled event when connecing ' leading to ' audio system 300 takes place, finish the loud speaker and definite frequency response and the distortion profile that detect in the audio system 300.
Control logic circuit produces control signal 604 based on the data that comprise the audio input signal level.Level detector 616 detects the level of audio input signal.Preferably, 620 pairs of audio input signals of low pass filter or band pass filter carry out pre-filtering (prefilter), so that the level of the signal after 616 detection filter of level detector.It preferably is the frequency that the frequency of the decay LF-response that can cause loud speaker is passed through with LPF Cutoff (cut-off) frequency configuration.If knownly some frequencies will be removed automatically from speaker output signal, then can use band pass filter, so that control logic circuit is only handled related signal band.In at least one embodiment, level detector 616 detects the average level of the audio input signal in the scheduled time slot.This scheduled time slot can be set to control logic circuit 602 and reserve the bass management that enough response times provide level to be correlated with.Control logic circuit 602 can also using system gain 608 provide better bass management.In at least one embodiment, the volume of system gain 608 expression audio systems 300.In another embodiment, system gain 608 also comprises the amplification of reprocessing arbitrarily.
The bass management systems 600 that level is relevant is handled the audio input signal that is used for each (pre-identified) loud speaker of discerning in advance.In at least one embodiment, Shi Bie loud speaker is to have benefited from the loud speaker of bass management in advance, and/or is used to provide the loud speaker of bass management by the bass management systems 600 that level is correlated with.In one embodiment, the loud speaker of identification is all loud speakers of audio system 300 in advance.Audio input signal signal
iExpression is used for the audio input signal level of i loud speaker, and wherein " i " is a member that can have in all set of speakers of discerning in advance of imperfect LF-response.612 couples of audio input signal signal of high pass filter 610 and low pass filter
iCarry out filtering.By passing through the cut-off frequency that signal is provided with high pass filter 610 and low pass filter 612.
Pass through the cross-over frequency that the cut-off frequency of signal filter 610 and 612 is set to determine.Control logic circuit determines whether to improve the ability of passing through the signal on the signal and being no more than the random component of audio system 300.If can be with signal signal
iBring up on the cross-over frequency, then improve audio input signal according to bass equalizer control signal EQ by equalizer 615.The low frequency that bass equalizer control signal EQ controls this audio input signal (for example, 0-200Hz) improves, and attempts to keep the flat frequency response of i loud speaker.If by improving audio input signal signal
iGain can not realize smooth LF-response, then control logic circuit 602 is used another kind of bass management solution, with the flat frequency response of whole expected level of realizing output signal when attempting to keep directivity and balance.Therefore, can (i) utilize the following audio input signal of PBE algorithm 618 enhancing cross-over frequencies and add it to audio input signal, if the woofer (low frequencycapable speaker) that perhaps (ii) can obtain producing the sound that does not have distortion (for example, subwoofer), then the audio input signal that is lower than cross-over frequency can be added into low frequency coding (LFE) input signal.(as shown) in one embodiment, the input signal that is used for woofer (low frequency capable speaker) is the LFE passage that is used for subwoofer.In another embodiment, if the loud speaker with directivity such as left side and right main speakers is available, then the bass management systems 600 that level is relevant can will keep the output signal of the main loudspeaker of directivity to attempt to keep directivity by low frequency signal is added into.Whether switch 614 carries out work according to control signal S1 will use PBE algorithm 618 with control, and whether the signal frequency that perhaps is lower than cross-over frequency will be routed to another loud speaker.Gain g1 and g2 are that much signal that produces to the PBE algorithm and problems that is routed to the signal of LFE loud speaker of gaining are used in design alternative and control.
In addition, the bass management systems 600 that level is relevant is attempted to keep balance in audio system 300.The bass management systems 600 that level is relevant passes through supporting passage (complimentary channel) is used same bass management solution, keeps balance in audio system 300.For example, route left channel low frequency audio frequency input signal component, then the bass management systems that level is relevant preferably is routed to low-frequency signal components another left speaker with the maintenance direction, and just supporting right channel low frequency component is routed to the right speaker corresponding to left speaker.If can not keep directivity, then left channel audio input signal and supporting right channel audio input signal all are routed to the loud speaker (such as subwoofer) with smooth LF-response.
In operation 706, level detector 616 detects audio input signal signal
iLevel.In operation 708, control logic circuit utilizes the level of configuration data 606 and detected audio input signal to produce appropriate control signals 604.Configuration data 606 expressions are included in the knowledge among frequency response curve 400 and the frequency curve 502-520.From frequency curve 502-520, can determine the THD and the loud speaker output level of the characteristic frequency of loud speaker.From frequency response curve 400, can determine the gain of the loud speaker in the full audio range.Be used to data, can determine audio input signal level and (choosing wantonly) system gain, unacceptable frequency range from Fig. 4 and Fig. 5, and definite cross-over frequency.For example, if for specified frequency, the audio input signal level that is used for i loud speaker adds that system gain adds that the speaker gain that is used for i loud speaker is within the zone of unacceptable THD, then is arranged on cross-over frequency on the assigned frequency.Preferably cross-over frequency is provided with, so that the loud speaker in the audio system 300 is avoided distortion, keeps directivity and obtained the frequency response of substantially flat.
Table 1 shows the example control signal data EQ that is used for the average peak audio input signal and passes through, and the instance system gain.In first example, total signal gain is-24dB.From curve 504 as can be seen, at the 100Hz place, can utilize equalizer 615 make the 100Hz place total signal gain gain increase+6dB with in the gain of the loud speaker shown in the compensating frequency response curve 400-6dB loss.Because the rapid gain of loud speaker descends and because the beginning of THD, so be positioned at or the frequency response that is lower than the frequency of about 90Hz is unacceptable.Right＜90Hz frequency carries out route or the PBE enhancing can influence directivity sharply.In the 3rd example, total signal gain is-18dB.As can be seen from Figure 5, for the frequency below the 150Hz, begin with rapid increase in the beginning of-THD of 18dB place.Therefore, cross-over frequency is set to 150Hz.Frequency response curve 400 shows the flat frequency response for bass frequencies, does not therefore need the bass isostatic compensation.The elaboration of other examples is with reference to same method.Therefore, by utilizing the relevant bass management of level, audio system 300 has been avoided distortion, has kept directivity, and has obtained the frequency response of substantially flat.
| Average peak input signal (dBFS) | System gain (dB) * | Total signal gain (dB) * | EQ (dB) | Cross-over frequency (Hz) | Note |
| ≤-18 | -6 | -24 | + 6@100Hz | 90 | Because loud speaker handles fully＞=and the frequency of 100Hz, thus kept whole directivity. |
| -15 | -6 | -21 | + 4@125Hz | 100 | |
| -12 | -6 | -18 | Do not have | 150 | |
| -6 | -6 | -12 | Do not have | 175 | |
| 0 | -6 | -6 | Do not have | 225 | Grievous injury directivity, but the infringement that loud speaker can not be transshipped. |
Table 1
With reference to figure 8, the bass management systems 800 that level is relevant has been described an embodiment of the system of the balance between relevant two audio signal channels of bass management operating period maintenance of level.Same method can be expanded to the balance in the passage that keeps arbitrary number.Level detector 802 detects audio input signal signal
iThe signal level of passage A (" passage A "), and signal detector 804 detects audio input signal signal
iThe signal level of channel B (" channel B ").In at least one embodiment, level detector 802 and 804 and level detector 616 play identical effect.Filter (not shown) such as low pass filter can be used for channel audio input signal A and B are carried out pre-filtering, thereby level detector 802 and 804 detects the level of related frequency range (such as low-frequency range).In at least one embodiment, passage A and B represent the supporting passage such as each left side voice-grade channel and right audio passage.
Decision logic (decision logic) 806 receives by level detector 802 and 804 level informations of determining.In one embodiment, decision logic 806 determines which has maximum signal level among passage A and the B.Decision logic 806 utilizes this to determine to come index signal treatment channel A assembly 808 and signal processing channel B assembly 810 according to the maximum of detected signal level passage A and B to be carried out identical processing.The bass management systems 600 that signal processing channel A assembly 808 and signal processing channel B assembly 810 are relevant with level is identical in essence.But, replacing the signal level of independent sense channel A and B, the maximum value signal level that will be determined by decision logic 806 is with the inputs of doing control logic circuit 602.
In at least one embodiment, signal processing channel A assembly 808 and signal processing channel B assembly 810 produce independent output a-signal and the B signal that is provided to drive independent loud speaker.If improve the low cut of low frequency signal with the output device of compensation such as loud speaker, then signal processing channel A assembly 808 and signal processing channel B assembly 810 also produce signal according to another kind of bass management solution.In one embodiment, signal processing channel A assembly 808 and signal processing channel B assembly 810 each LFE that produce separately export (LFE out) signal A and B.The loss of the low-signal frequencies response in LFE output signal compensation output a-signal and the output B signal.Owing to generally having only a LFE output device, therefore LFE is exported a-signal and LFE and export the B signal and expect that at first the LFE input signal mixing of supplying with the use of LFE device is to produce the LFE output signal such as subwoofer.This LFE output signal is offered low frequency output device such as subwoofer.
Can in the combination of hardware, software or hardware and software, realize the bass management systems 800 that this level is relevant.If processing speed is enough big, then can only utilizes a signal processing component to realize the bass management systems 800 that level is relevant, and time-division (timedivision) can be used for treatment channel A and B.
Therefore, at least one embodiment, the bass management systems that the level of signal processing system is relevant is designed to low frequency is produced the flat frequency response, prevents the distortion of audio output device and the directivity that keeps sound.
Although described the present invention in detail, should be appreciated that and do not deviating under the situation of the spirit and scope of the present invention as defined by the appended claims, can carry out various changes, replacement, and change it.
Claims (43)
1. one kind provides the level method that relevant low frequency is managed in signal processing system, and described method comprises:
Receive the audio input signal that is associated with first loud speaker at least, wherein, the signal in described first loud speaker decay low-frequency range;
The amount that is no more than one or more acceptable restrictions of described signal processing system to be enough to compensate the low cut of described first loud speaker at least in part improves the component of the described audio input signal in the described low-frequency range; And
Limit under the situation of the described low cut of low frequency being brought up to described first loud speaker of basic compensation in the low-frequency level of described audio input signal and one or more restrictions of described signal processing system, utilize candidate's low frequency rwan management solution RWAN to come described audio input signal is handled.
2. method according to claim 1, wherein, described candidate's low frequency rwan management solution RWAN comprises:
The component of the described audio input signal in the described low-frequency range is handled the signal that is used to be routed to second loud speaker with generation.
3. method according to claim 2, wherein, the component of described audio input signal is brought up to first level, the described signal that is used to be routed to described second loud speaker has second level, and described first level and the described second level sum equal the level of the described audio input signal in the described low-frequency range.
4. method according to claim 1, wherein, described candidate's low frequency rwan management solution RWAN comprises:
For the level of described audio input signal, with the frequency component of the described audio input signal of psycho-acoustic bass extension algorithm application in the unacceptable frequency response range of described first loud speaker.
5. method according to claim 1, wherein, described candidate's low frequency rwan management solution RWAN comprises one or more parts of following group, described group comprises:
(i) component of the described audio input signal in the described low-frequency range is handled, be used to be routed to the output signal of second loud speaker with generation;
(ii) for the level of described audio input signal, with the frequency component of the described audio input signal of described psycho-acoustic bass extension algorithm application in the unacceptable frequency response range of described first loud speaker;
(iii) the amount that is no more than one or more acceptable restrictions of described signal processing system to be enough to compensate the low cut of described first loud speaker is at least in part come the lasting component that improves the described audio input signal in the described low-frequency range.
6. method according to claim 1, wherein, the described low-frequency level of described audio input signal comprises the average peak level in the scheduled time slot.
7. method according to claim 1, wherein, the described low-frequency level of described audio input signal comprises the set of the audio input signal level of each frequency component that is used for described audio input signal.
8. method according to claim 1, wherein, the component that improves the described audio input signal in the described low-frequency range further comprises:
The only gain that improves described audio input signal with the amount of the frequency response of the substantially flat that keeps described first loud speaker.
9. method according to claim 1 further comprises:
Utilize high pass filter and low pass filter that described audio input signal is carried out filtering, wherein, the cut-off frequency of described high pass filter and the cut-off frequency of described low pass filter depend on the described low-frequency level of described audio input signal, and the described cut-off frequency of described low pass filter limits the upper limiting frequency of described low-frequency range.
10. method according to claim 1 further comprises:
Pre-determine a plurality of acceptable restriction of described signal processing system for a plurality of low-frequency level of described audio input signal.
11. method according to claim 1 further comprises:
Basic directivity and the balance that keeps described audio input signal during raising and processing.
12. method according to claim 11 wherein, keeps the directivity and the balance of described audio input signal to comprise in raising with during handling substantially:
Determine two maximum signal levels between the supporting audio signal channel; And when improving and handle described two supporting audio signal channels of described audio input signal, with the described low-frequency level of maximum signal level as described audio input signal.
13. the signal processing system that the relevant bass frequencies management of audio input signal level is provided, described system comprises:
Input is used to receive the audio input signal that is associated with first loud speaker at least; And
The bass frequency management system that level is relevant comprises:
Detector, it is in response to the level of described audio input signal;
Amplifier; And
Control logic circuit, be used to the amount that makes described amplifier be no more than one or more acceptable restrictions of described signal processing system to be enough to compensate the low cut of described first loud speaker at least in part, improve the component of the described audio input signal in the described low-frequency range, and be used for limiting under the situation of the described low cut of described low frequency being brought up to described first loud speaker of basic compensation in the low-frequency level of described audio input signal and one or more restrictions of described signal processing system, make the relevant bass frequency management system of described level utilize candidate's low frequency rwan management solution RWAN to come described audio input signal is handled.
14. system according to claim 13, wherein, described candidate's low frequency rwan management solution RWAN comprises and is used for the described audio input signal in the described low-frequency range is handled the one or more assemblies that are used to be routed to the signal of second loud speaker with generation.
15. system according to claim 13, wherein, described candidate's low frequency rwan management solution RWAN comprises for the level of described audio input signal and with one or more assemblies of the frequency component of the described audio input signal of psycho-acoustic bass extension algorithm application in the unacceptable frequency response range of described first loud speaker.
16. system according to claim 13, wherein, described candidate's low frequency rwan management solution RWAN comprises one or more assemblies of the one or more processing that are used for carrying out following group, and described group comprises:
(i) component of the described audio input signal in the described low-frequency range is handled, be used to be routed to the output signal of second loud speaker with generation;
(ii) for the level of described audio input signal, with the frequency component of the described audio input signal of described psycho-acoustic bass extension algorithm application in the described unacceptable frequency response range of described first loud speaker; And
(iii) the amount that is no more than one or more acceptable restrictions of described signal processing system to be enough to compensate the low cut of described first loud speaker is at least in part come the lasting component that improves the described audio input signal in the described low-frequency range.
17. system according to claim 13 wherein, utilizes at least one member in the following group to realize the bass frequency management system that described level is relevant, described group comprises: the circuit that software, rigid line connect, and Programmable Logic Device.
18. system according to claim 13, wherein, the described low-frequency level of described audio input signal comprises the average peak level in the predetermined period.
19. system according to claim 13, wherein, the described low-frequency level of described audio input signal comprises the set of the audio input signal level of each frequency component that is used for described audio input signal.
20. system according to claim 13, wherein, in order to improve the component of the described audio input signal in the described low-frequency range, the relevant bass frequency management system of described level increases the level that improves the described audio input signal in the described low-frequency range up to the amount of the frequency response of the substantially flat that produces described loud speaker by the gain with described audio input signal.
21. system according to claim 13 further comprises:
High pass filter is used to receive described audio input signal; And
Low pass filter, be used to receive described audio input signal, wherein, the cut-off frequency of described high pass filter and the cut-off frequency of described low pass filter depend on the described low-frequency level of described audio input signal, and the described cut-off frequency of described low pass filter limits the upper limiting frequency of described low-frequency range.
22. system according to claim 13, wherein, the bass frequency management system that described level is relevant further comprises:
Memory is connected to control logic circuit and signal change assembly, and the predetermined change of storing the described audio input signal of a plurality of level that are used for described audio input signal.
23. system according to claim 13, wherein, described control logic circuit is basic directivity and the balance that keeps described audio input signal during raising and processing also.
24. system according to claim 23 further comprises:
Another level detector, wherein, described level detector is in response to each supporting signalling channel level of described audio input signal;
Decision logic is used for the maximum signal level between definite described each supporting audio signal channel;
Wherein, when improving and handle the supporting audio signal channel of two of described audio input signal, described control logic circuit is with the described low-frequency level of described maximum signal level as described audio input signal.
25. a signal processing system that comprises the bass frequency management system that the audio input signal level is relevant, the bass frequency management system that described level is relevant comprises:
Input is used to receive the audio input signal that is associated with first audio output device at least;
Equalizer; And
Control logic circuit, be connected to described input, be used for:, then make described equalizer improve the described frequency component of described audio input signal with the frequency response of compensate for attenuation at least in part if (i) described audio input signal comprises having the frequency component of frequency that is positioned at or is lower than the level of first level and has the LF-response district of the decay that is positioned at described first audio output device; And if (ii) described frequency component has greater than the level of described first level and improve under described frequency component is subjected to described signal processing system with the frequency response of basic compensate for attenuation the situation of restriction of one or more restrictions, then utilize candidate's low frequency rwan management solution RWAN to handle the frequency component of described audio input signal.
26. signal processing system according to claim 25 further comprises:
Level detector is used to detect the level to the described audio input signal of the relevant bass frequency management system of described level.
27. signal processing system according to claim 26 further comprises:
Band pass filter, be connected to described level detector, be used for described audio input signal is carried out filtering, and filtered audio input signal provided to described level detector, wherein, the frequency passband with described band pass filter is configured such that the audio input signal that causes the low-frequency distortion in one or more audio output devices passes through.
28. signal processing system according to claim 25 further comprises:
High pass filter is used to receive described audio input signal; And
Low pass filter, be used to receive described audio input signal, wherein, the cut-off frequency of described high pass filter and described low pass filter depend on the low-frequency level of described audio input signal by frequency, the described cut-off frequency of described low pass filter limits the upper limiting frequency of described low-frequency range.
29. signal processing system according to claim 25, wherein, described control logic circuit further comprises the processor that is used for the processing configuration data, wherein, described configuration data is associated with a plurality of audio output devices of the described signal processing system that comprises first audio output device, and described configuration data comprises the whole harmonic distortion data that are used for a plurality of signal levels and a plurality of signal frequencies.
30. signal processing system according to claim 25, wherein, described control logic circuit comprises the control signal of the low frequency rwan management solution RWAN that is used to control equalizer and described candidate, described control signal comprises the cross-over frequency control signal of representing cross-over frequency and is used to control the equalizer control signal of the gain of described audio input signal that the management system of the bass frequencies that described level is relevant further comprises:
High pass filter, be connected to described control logic circuit to receive described cross-over frequency control signal, and described audio input signal carried out filtering, wherein, described cross-over frequency control signal is arranged on the frequency place that allows at least one described audio output device to produce the sound of non-distortion with the cut-off frequency of described high pass filter; And equalizer input, be connected to described control logic circuit, be used to receive described equalizer control signal, wherein, described equalizer is connected to described high pass filter to receive the output of described high pass filter, and be connected at least one described audio output device, wherein, described during operation equalizer control signal makes described equalizer improve the frequency component of described audio input signal.
31. signal processing system according to claim 25, wherein, described candidate's low frequency rwan management solution RWAN comprises psycho-acoustic bass extension (" PBE ") algorithm, described control logic circuit comprises control signal, described control signal comprises the cross-over frequency control signal of representing cross-over frequency and is used to control the PBE control signal of described PBE algorithm that the bass frequency management system that described level is relevant further comprises:
Low pass filter, be connected to described control logic circuit to receive described cross-over frequency control signal, and described audio input signal carried out filtering, wherein, described cross-over frequency control signal is arranged on the frequency place that allows at least one described audio output device to produce the sound of the non-distortion that is associated with described PBE algorithm with the cut-off frequency of described low pass filter; And
Wherein, the PBE algorithm is configured to strengthen by the filtered described audio input signal of low pass filter according to described PBE control signal.
32. signal processing system according to claim 25, wherein, described candidate's low frequency rwan management solution RWAN comprises psycho-acoustic bass extension (" PBE ") algorithm, described control logic circuit comprises control signal, described control signal comprises the cross-over frequency control signal of representing cross-over frequency and is used to control will expect that some signal frequencies of supplying with first audio output device are routed to the route control signal of one or more low frequency audio output devices, and the bass frequency management system that described level is relevant further comprises:
Low pass filter, be connected to described control logic circuit to receive described cross-over frequency control signal, and described audio input signal carried out filtering, wherein, described cross-over frequency control signal is arranged on the cut-off frequency of described low pass filter at the frequency place of the signal frequency of first audio output device that leaches a plurality of described audio output devices of expection supply; And
Circuit is connected to described low pass filter, is used to receive described route control signal, and will expect that according to described route control signal some signal frequencies of supplying with described first audio output device are routed to described one or more low frequency audio output device.
33. signal processing system according to claim 25, wherein, the level of described audio input signal is the average level in the period.
34. signal processing system according to claim 25 wherein, utilizes the one or more members in the group comprise circuit that rigid line connects and Programmable Logic Device to realize described control logic circuit.
35. signal processing system according to claim 25, wherein, described first audio output device is first loud speaker, and described signal processing system further comprises described first loud speaker and a plurality of other loud speakers that are connected to the relevant bass frequency management system of described level.
36. system according to claim 13, wherein, described control logic circuit also keeps the directivity and the balance of described audio input signal substantially during raising and processing.
37. the equipment that the relevant bass frequencies management of audio input signal level is provided, described equipment comprises:
Receiving system is used to receive the audio input signal that is associated with first loud speaker at least, wherein, and the signal in described first loud speaker decay low-frequency range;
Improve device, be used for the amount that is no more than one or more acceptable restrictions of described signal processing system to be enough to compensate the low cut of described first loud speaker at least in part, improve the component of the described audio input signal in the low-frequency range; And
Processing unit, be used for having limited under the situation of the described low cut of described low frequency being brought up to described first loud speaker of basic compensation, utilize candidate's low frequency rwan management solution RWAN to come described audio input signal is handled in the low-frequency level of described audio input signal and one or more restrictions of described signal processing system.
38. according to the described equipment of claim 37, wherein, described raising device further comprises:
Only be used for increasing the device of the gain of described audio input signal with the amount of the frequency response of the substantially flat that keeps described loud speaker.
39. further comprise according to the described equipment of claim 37:
Be used for the frequency component of described audio input signal is routed to the device of second loud speaker, wherein, the described frequency component that is routed to described second loud speaker comprises by the frequency component in the described low-frequency range of described first loud speaker decay.
40. further comprise according to the described equipment of claim 37:
For the described level of described audio input signal, be used for device with the frequency component of the described audio input signal of psycho-acoustic bass extension algorithm application in the unacceptable frequency response range of described first loud speaker.
41. according to the described equipment of claim 37, wherein, described candidate's low frequency rwan management solution RWAN comprises the one or more members in the following group, described group comprises:
(i) be used for the described component of the described audio input signal in the described low-frequency range is handled, be used to be routed to the device of the output signal of second loud speaker with generation;
(ii), be used for device with the frequency component of the described audio input signal of described psycho-acoustic bass extension algorithm application in the unacceptable frequency response range of described first loud speaker for the described level of described audio input signal; And
(iii) be used for the amount that is no more than one or more acceptable restrictions of described signal processing system to be enough to compensate the low cut of described first loud speaker at least in part, continue to improve the device of the component of the described audio input signal in the described low-frequency range.
42. further comprise according to the described equipment of claim 37:
Be used to utilize high pass filter and low pass filter described audio input signal to be carried out the device of filtering, wherein, the cut-off frequency of described high pass filter and the cut-off frequency of described low pass filter depend on the described low-frequency level of described audio input signal, the described upper limiting frequency that limits described low-frequency range by frequency of described low pass filter.
43. further comprise according to the described equipment of claim 37:
Be used to pre-determine the device of change of the described audio input signal of a plurality of level that are used for described audio input signal.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US69573105P | 2005-06-30 | 2005-06-30 | |
| US60/695,731 | 2005-06-30 | ||
| US11/238,338 | 2005-09-29 |
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| CN101213869A true CN101213869A (en) | 2008-07-02 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111052601A (en) * | 2017-09-07 | 2020-04-21 | 思睿逻辑国际半导体有限公司 | Loudspeaker distortion reduction |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111052601A (en) * | 2017-09-07 | 2020-04-21 | 思睿逻辑国际半导体有限公司 | Loudspeaker distortion reduction |
| CN111052601B (en) * | 2017-09-07 | 2024-01-30 | 思睿逻辑国际半导体有限公司 | Method and apparatus for reducing audio distortion in a speaker |
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