Patent Grant
11722831
The invention relates to a method for reproducing audio in a multi-channel sound system comprising two input signals L and R, wherein output signals are generated for different listening levels.
Methods of the above-mentioned type are known to those skilled in the art and represent a further development of a conventional surround sound system, an audio reproduction, which takes place only at the ear level, that is, at the lower listening level.
For the three-dimensional audio reproduction in a multi-channel sound system, a higher listening level is added to the lower listening level. Herein also lies the decisive advantage of the method of the above-named type, since the human ear can perceive and differentiate upwardly staggered sounds clearly, so that the listener, due to the three-dimensional loudspeaker arrangements, enjoys the pleasure of an expanded sound experience. Methods of the above-named type have been developed mainly for audio signals in large rooms, such as cinema auditoriums.
In the prior art, different views are represented as to which speaker configurations or type of generating the three-dimensional sound, whether channel-based or object-based, lead to an optimum audio experience, wherein either the multichannel recording and reproduction of a three-dimensional audio space, as described in WO 01/47319 A2, or the upmix of variable input channels to a three-dimensional audio room offered by various providers are in the foreground of consideration. The three-dimensional audio systems of Dolby Laboratories, for example, have up to 64 loudspeakers (such as Dolby Atmos), which, in turn, require a corresponding number of output signals.
It is a common feature of all the methods named above that a complex loudspeaker configuration and, accordingly, a correspondingly larger number of output signals are required in order to generate the desired three-dimensional sound space.
Even a loudspeaker configuration in a 9.1 three-dimensional sound system, which is suitable, for example, for a home cinema, consists of 10 loudspeakers, which, in turn, require a corresponding number of output signals for the lower and upper listening levels.
In accordance with the present prior art, it is possible only with difficulty for consumers, who are used to AV equipment (audio video equipment), to have the enjoyment of the advantages of three-dimensional audio reproduction, since it is reserved for only a few to acquire the costly equipment with a three-dimensional audio reproduction and only a limited number of consumers have suitable rooms, in which it is possible to accommodate a larger number of loudspeakers with their cables. The reality therefore is that, admittedly, cinemas, music studios or also selected concert halls have the technical equipment for three-dimensional audio reproduction, but that this does not enter into the everyday life of those who would like to have the advantages of three-dimensional audio reproduction in a simple and uncomplicated manner, with a few, easy steps and with, comparatively, a low budget, for example, at the workplace or in the living room or while traveling.
It is therefore an object of the invention to develop a method of the above-mentioned type, so that these disadvantages are eliminated.
This object is solved by the features of claim 1. Advantageous configurations of the invention are described in the dependent claims.
The invention provides that only one lower listening level and only one upper listening level are generated, wherein a maximum of six output signals are generated with no more than two output signals for the lower listening level and no more than four output signals for the upper listening level.
The core idea of the invention is to make a method available, which, by generating the least possible number of output signals, can reflect a three-dimensional audio reproduction and cover the mono region as well as the stereo region.
This results in the smallest unit, which, advantageously, can be expanded in modular fashion in that the output signals serve as further input signals, in order to generate further lower and upper listening levels and, accordingly, an even more complex loudspeaker configuration.
By means of the method according to the invention and the software corresponding thereto, it is possible, for example, to realize the increased sound level by adding two small loudspeakers to domestic television sets or to laptops.
In an advantageous configuration of the invention, channels are decoded for the input channels provided for the input signals R and L. These channels preferably are a left spatial channel RL=L−R, a right spatial channel RR=R−L and a center channel C=L+R. Advisably, linear and parallel channels R and L, which preferably serve as output channels for the lower listening level, are generated to these decoded channels from the input channels. Practical variations of the invention generate stereo signals or respectively mono signals for the signals in the lower and upper listening level.
A device with sound input and sound output channels, as well as with a processor, loudspeakers being assigned to the processor, is the subject matter of claim 10, wherein a software is ported onto the processor and contains an algorithm, which is processed by the processor, the algorithm covering the method of one of the claims 1 to 9.
A software, which is on a signal processor, that is, ported onto the signal processor, is also provided within the scope of the invention. The software contains an algorithm, which is processed by the signal processor, the algorithm covering the method.
In the following, the invention is explained in greater detail by means of the drawings. In diagrammatic representation,
The upper listening level 4a, with two loudspeakers with the left higher signal LHi and the right higher signal RHi as output signals, are in the front area of the room 2. Furthermore, the lower listening level 5a with four loudspeakers with the left signal L, the channel C (Center), the right channel R and the LFE (low frequency effect) channel as output signals, are in the front area of the room 2. The upper listening level 4b with two loudspeakers with the left, higher surround signal SL,hi and the right, higher surround signal SR,hi as output signals, are in the rear region of the room 2. The lower listening level 5b with two loudspeakers with the two surround signals SL, SR as output signals is in the front region of the room 2.
Before the signals are distributed in the lower and upper listening levels 4a, 4b, 5a, 5b to the loudspeakers, they are processed within the scope of a multichannel sound system and, starting out from the input signals R and L, by an audio processor intended for this purpose.
As furthermore shown in
In particular, the method sections are
To begin with, three channels are decoded from the two output signals L and R and formed parallel next to the channels 8, 9, which are guided linearly to the output. The upper listening level 6 arises by these means, while the channels 8, 9, which are guided linearly to the output, form the lower listening level 7.
The decoded channels are the left spatial channel RL=L−R, the right spatial channel RR=L−R and the center channel L+R.
The channels RL and R, illustrate the premises and reflections within the input signals L, R, whereas the channel C (center channel) depicts the addition of both input channels L, R. By these means, it is possible to process the input signals L, R further, when it is a question of a mono signal. If there is a mono signal at the input, the channels RL and R, remain mute and the channel C passes on the signal information and thus makes the further signal processing possible.
After this encoding step, the channel R, is passed into the signal detector 10. The latter issues the control signal “1”, when the signal strength of R, falls below the threshold level selected, and the control signal “0”, when the level of the channel R, rises above the selected threshold level. The threshold level is −20 dB and the reaction time (trigger) zero seconds.
The control signals of the signal detector 10 are multiplied by the signal multiplier 11 with the signal of the center channel. If no recognized signal is present in the channel RR, so that there is no stereo signal in the channels RL and RR above or equal to the signal strength specified by the threshold level and the signal detector 10 generates the control signal “1”, the channel C is multiplied by “1” and supplied to a further processing. If a recognized signal is present in the channel RR, so that a stereo signal is in the channels RL and RR above or equal to the signal strength specified by the threshold level and the signal detector 10 generates the control signal “0”, the channel C is multiplied by “0” and not released for further processing, since the signal is equal to zero, so that it is recognized unequivocally whether a stereo signal is present.
In order to avoid a phase shift of the channels RL, RR, a phase correction is made in a next step of the method, as furthermore shown clearly in
In order to intensify the later impression of a reflection for the upper listening level 6, the phase of the channel C is also adjusted and, moreover, by a delay 13, which is used on the channel CR, after the channel C (L+R) has been split into the channels CL and CR after the signal multiplier 11 and continued in this fashion in dual mono channels. The channel C is strictly a mono channel and can be converted into a stereo signal by splitting into the two duo mono channels CL and CR and the retardation of the channel CR to the channel CL by a delay and, moreover, with a phase correlation above 0. By these means, the audio impression of an increased diffusivity of the original signal results and contributes to the impression of the tonal range of heightened hearing, since a mono signal, which was recorded with microphones installed in an elevated position, is reproduced also not linearly but diffusely and afflicted with reflections, depending on the nature of the recording room and the height of the installed microphones.
Within the scope of a further step of the method, the frequency of the center channel C is adjusted by means of the equalizer 14. The frequency adjustment of channel C adjusts the frequency-dependent reproduction of the latter in the later output signals LHi, RHi of the upper perception level 6 and, moreover independently of the later frequency adjustment of the output signal. By these means, the sound character of the output signals LHi, RHi can be adjusted optimally to the AV equipment shown in
In order to intensify the auditory impression of a “sound reflection upward”, the signals Lt and Rt, as is furthermore evident from
By using an echo and/or a stereo delay 21, which are mixed with the signal Lt, Rt in a ratio which can be adjusted individually and according to the type of use of the method, a room as well as a sound delay is portrayed. By these means, it is ensured that the output signals LHi, RHi of the upper listening level 6 can also portray various rooms and sound delays through the use of different presets, which can be saved, in order to be able to match the sound result even more closely to a true “sound reflection upwards” as well as to the individual sound conceptions of the manufacturer and/or the user.
In order to intensify the hearing sensation that the output signals LHi, RHi reproduce sound “which comes up from below” even further, a compression step is inserted into the master section, as shown in
The level adjustment of the channels Lt,Hi, Rt,Hi at the level adjusters 23, 24 is a further step of the method, in that the output level is adjusted in relation to channels of the lower listening level 7, so that the impression of heightened hearing can be matched perfectly to the respective hearing situation. Alternatively, it is also possible to mix the audio signal Lt,Hi, Rt,Hi once again with the channels L, R, in order to be able to portray an enhanced sound impression also in loudspeaker systems with only two loudspeakers or even only one.
The following parameters come into consideration for the individual steps of the method.
Phase correction:
The levels are adjusted so that the encoded summing up of the channels RL, RR, CL, CR has the same level (dB) as that of RL, RR before the summing up.
Master Section/Frequency Adjustment:
Individually adjustable, no ideal settings, depends on the method used. Advantageously, the decay for echo is brief, that is, decay times of 0.51 seconds to 0.67 seconds and a pre-delay of 20 milliseconds
Master Section/Compression:
The level can be adjusted individually for the device and the environment, in which the method is to be used.
AV equipment, such as a television set (TV) and a flat screen set 28, shown in
A mobile PC 25 (
A sound bar 33 is also, as is evident from
The embodiments of the present invention are not limited to the examples given above. Rather, a number of variations is conceivable, which make use of the solution shown also for embodiments of a different type. For example, the channels 8, 9 in the lower listening level 7 can also be processed further.
The inventive principle of the modular-like, expandable smallest unit of a signal generation, which leads to complex loudspeaker configurations, is also illustrated in
Starting out from the two input channels R and L, the left output signal LHi and the right output signal RHi are generated in the lower listening level 7 and the upper listening level 6 by means of an algorithm in the signal processor 34, so that, to begin with, four output signals, two for the upper listening level 6 and two for the lower listening level 7, are generated.
As it is furthermore evident from
The output signals R and L in the lower listening level 7 are then taken as channels L1 and R1 directly to the loudspeakers 36, 37 of the soundbar 40. At the same time, the output signals R and L serve as input signals R and L, in order to generate a lower listening level 7 and an upper listening level 6 once more within the scope of the method according to the invention. This takes place again by means of the algorithm in the signal processor 34, on which the software is located. The software contains an algorithm, which is processed by the signal processor.
Starting out from the splitting of the input signals R and L, the output signals R and L are generated in the lower listening level 7 and, in the upper listening level 6, the left output signal LHi and the right output signal RHi are generated, so that, once again, four output signals are generated, two for the upper listening level 6, that is, LHi and RHi, and two for the lower listening level 7, that is, L and R. Subsequently, the signals LHi and RHi are mixed with the signals R and L in the lower listening level 7, that is, is added to the signal L and RHi to the signal R. By these means, the added or mixed signals in the lower listening level are supplied to two further loudspeakers 38, 39 of the sound bar 40. Accordingly, the sound bar 40 has a total of five output channels, namely four output signals R, L, LHi+L, RHi+R in the lower listening level 7 and one output signal LHi+RHi in the upper listening level 6. All output channels can be processed further by the level control, the equalizer, the compressor etc.
The variation of a modular-like, expandable smallest unit, shown in
The embodiment of the method according to the invention, shown in
The further LFE channel is guided directly to its own outlet and, as LFE output channel, is supplied there to a further loudspeaker. This output channel, like all the other output channels, can also be processed further by a level control, equalizer, compressor, etc. The loudspeaker configuration of audio equipment, which corresponds to the embodiment described in connection with
It is a common feature of both the embodiments shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2014 100 049.8 | Jan 2014 | DE | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 6122382 | Iida | Sep 2000 | A |
| 20040125967 | Eid | Jul 2004 | A1 |
| 20090060237 | Konagai | Mar 2009 | A1 |
| 20100303246 | Walsh | Dec 2010 | A1 |
| 20130208895 | Horbach | Aug 2013 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20220070602 A1 | Mar 2022 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15109676 | US | |
| Child | 17470439 | US |
