WO2007109830A1 - Volume control device and distributed audio system - Google Patents
Volume control device and distributed audio system Download PDFInfo
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- WO2007109830A1 WO2007109830A1 PCT/AU2007/000255 AU2007000255W WO2007109830A1 WO 2007109830 A1 WO2007109830 A1 WO 2007109830A1 AU 2007000255 W AU2007000255 W AU 2007000255W WO 2007109830 A1 WO2007109830 A1 WO 2007109830A1
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- WIPO (PCT)
- Prior art keywords
- output
- signals
- amplifier
- volume control
- input
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04S—STEREOPHONIC SYSTEMS
- H04S7/00—Indicating arrangements; Control arrangements, e.g. balance control
Abstract
A volume control apparatus, comprising an input for receiving input signals, a preamplifier for receiving signals from the input, an onboard amplifier for receiving signals from the preamplifier, a first output for outputting signals from the onboard amplifier, and a second output for outputting signals comprising or derived from the input signals without amplification by the onboard amplifier. Output from the second output is suitable for inputting into an external amplifier. The invention also provides a distributed audio system with one of more such volume control apparatuses.
Description
VOLUME CONTROL DEVICE AND DISTRIBUTED AUDIO SYSTEM
Related Application
This application is based on and claims the benefit of the filing date of AU application no. 2006100238 filed 28
March 2006, the content of which is incorporated herein by reference in its entirety.
Field of the Invention The present invention relates to distributed audio system./ and to a volume control device for use therein.
Background of the Invention
There exist a number of music distribution systems with powered volume controls. Such volume controls house a pre-amplifier and a small power amplifier for connection to speakers near the volume control . An analogue audio signal is transmitted from an audio player to the volume control (and hence preamplifier) , the suitably (pre-) amplified analogue signal is then transmitted to the power amplifier, and the resulting signal is output to the speakers .
Another existing system includes a volume control wall plate that includes a pre-amplifier (again, for receiving an analogue audio signal from the audio player) , with an amplifier located either in each speaker or separately housed near the speakers for receiving the (pre-) amplified analogue signal from the pre-amplifier, amplifying it and passing it to the speakers.
Summary of the Invention
The present invention provides, therefore, a volume control apparatus, comprising: an input for receiving input signals; a preamplifier for receiving signals from said input;
an onboard amplifier for receiving signals from said preamplifier; a first output for outputting signals from said onboard amplifier; and a second output for outputting signals comprising or derived from said input signals without amplification by said onboard amplifier; wherein output from said second output is suitable for inputting into an external amplifier.
The output from the second output may comprise the output of the preamplifier. Alternatively, output from the second output may comprise some or all of the input signals, such as from a looped terminal connected to the input (such that the output from the second output has the same level characteristics as the input signals) . In one embodiment, the output from the second output is received from the onboard amplifier, but with the onboard amplifier operated so that it provides no amplification.
Thus, a user can use the output from the first output (i.e. amplified by the onboard amplifier of the volume control apparatus) , or the output from the second output (and typically amplify that output by means of an external, more powerful amplifier) , or both. The apparatus thus can operate as a preamplifier with inbuilt amplifier, as a preamplifier to control an additional stand-alone external amplifier, or merely to pass the input signals to the second output (for transmission to an external amplifier) and provide control signals for controlling the (for example, volume of the) external amplifier but with no pre-amplification or amplification.
In one embodiment, the volume control apparatus includes a switch with a first setting for directing the output of the preamplifier to the onboard amplifier and a second setting for directing the signals from the preamplifier to
the second output .
The switch may include a third setting that directs the signals from the preamplifier to both the onboard amplifier and the second output.
In another embodiment, the apparatus includes a switch with a first setting in which the output of the preamplifier is passed to the onboard amplifier and a second setting in which the output of the preamplifier is not passed to the onboard amplifier. In this embodiment, the input signals may be permanently available at the second output (for example, for transmission to an external amplifier) .
In one particular embodiment, the first output and the second output are provided as a combined output, and the apparatus includes a switch with a first setting for directing an output of the preamplifier to the combined output via the onboard amplifier and a second setting for directing the output of the preamplifier to the combined output without passing via the onboard amplifier.
Hence, in this embodiment, the combined output acts as the first output when the output signals from the preamplifier are directed to the combined output via the onboard amplifier, and as the second output when the output signals from the preamplifier are directed to the combined output without passing via the onboard amplifier.
One of the benefits of the apparatus of the invention is that it allows a user to employ the onboard amplifier of the apparatus, and later to upgrade by adding an external amplifier and employing the second output, without changing any of the original hardware. As the external amplifier would typically be of a much higher audio fidelity, the invention allows that upgrade by the user by
adding the external amplifier, while avoiding any need to replace the apparatus of the invention.
Another advantage of the apparatus of the invention is that it allows the user to employ both the onboard amplifier and an external amplifier, such as to provide audio in respective areas where lower fidelity and higher fidelity are desired. The apparatus of the invention also allows a plurality of like volume control apparatuses to be used powered from a single power supply, if the onboard amplifier is switched off the current consumption of any single volume control apparatus is low.
In one embodiment, the apparatus includes a control output for controlling an external amplifier (such as to turn it on or into a standby mode) . Thus, the external amplifier need not consume full power when the apparatus is itself turned off. The apparatus may also include a power switch to switch the onboard amplifier on and off to save power consumption when the second output is in exclusive use
(with, for example, an external amplifier) .
In one embodiment, the apparatus includes a control circuit for outputting a control signal adapted to control an external amplifier (such as to switch off or to go into a standby mode) .
The invention also provides a distributed audio system includes a volume control apparatus as described above. In one embodiment, the volume control apparatus is one of a plurality of like volume control apparatuses.
Brief Description of the Drawing In order that the invention may be more clearly ascertained, preferred embodiments will now be described, by way of example, with reference to the accompanying drawing, in which:
Figure 1 is a schematic view of a distributed audio system according to an embodiment of the present invention;
Figure 2 is a schematic view of a distributed audio system according to another embodiment of the present invention;
Figure 3 is a schematic view of a distributed audio system according to a further embodiment of the present invention; Figure 4 is a schematic circuit diagram of the amplified volume control of the distributed audio systems of figures 1 to 3 ;
Figure 5 is a schematic circuit diagram of an amplified volume control according to another embodiment of the present invention for the distributed audio systems of figures 1 to 3; and
Figure 6 is a schematic circuit diagram of an amplified volume control according to another embodiment of the present invention for the distributed audio systems of figures 1 to 3.
Detailed Description of the Embodiments
A distributed audio system according to an embodiment of the present invention is shown generally at 10 in figure 1. The system 10 includes an audio player 12 and is designed to allow the output of audio player 12 to be played - and its volume controlled - through speakers disposed remotely from the audio player 12, typically in other rooms .
The audio player 12 may be in the form of any audio player with suitable output, such as a CD player, MP3 player, personal computer, television tuner, radio tuner or DVD player. System 10 also includes a wall mounted input module 14 (connected to the output terminals 16 of the audio player 12 by electrical cables 18) , which includes a wall plate 20 and RCA input jacks 22, and converts the
signal from the audio player 12 to a balanced signal. It should be noted that, while system 10 has one input module, in other embodiments a plurality of input modules may be included in the system, each with its own output so that the user can select which audio signal is to be distributed by the system.
The system 10 includes a volume control apparatus, with which a user can control the audio volume output by the system, in the form of a first amplified volume control 24. First amplified volume control 24 is the principal mechanism by which the volume of the system 10 is controlled by a user when remote from the audio player 12. Amplified volume control 24 has an onboard preamplifier (not shown: see figure 4) and an onboard low powered amplifier (not shown: see figure 4) of, in this embodiment, 6W.
System 10 includes an electrical cable 26 for connecting input module 14 and first amplified volume control 24. Electrical cable 26 is in the form of an 8 conductor twisted pair cable, and carries the aforementioned balanced signal. The system 10 includes an external amplifier 28 (viz. external with respect to first amplified volume control 24) , typically located in a ceiling cavity or other nearby location, and a set of speakers 30, connected to the output of external amplifier 28. External amplifier 28 is powered either by a remote power supply (not shown in this figure, but see figures 4 and 6) or a local power source, such as 230 V (or local equivalent) plus power supply.
In the embodiment of figure 1, the onboard amplifier of amplified volume control 24 is turned off and the onboard preamplifier of amplified volume control 24 is connected by cables 32 to external amplifier 28. Thus, first amplified volume control 24 operates as a preamplifier to
drive the external amplifier 28 and hence speakers 30.
Amplified volume control 24 also has an infrared sensor (not shown) and can be controlled by means of an infrared remote control (also not shown) . This also allows the audio player 12 to be controlled remotely: infrared signals received by first amplified volume control 24 and determined by the amplified volume control 24 to be adapted to control the audio player 12 are converted by first amplified volume control 24 into electrical signals and transmitted along 8 conductor twisted pair cable 26 to the input module 14. Input module 14 passes this signal to its λ infrared' output 34 (though still as an electrical signal) . The system 10 also includes an infrared repeater 36, connected to infrared output 34 of input module 14; the infrared repeater 36 converts any received signal back into infrared and transmits the resulting infrared signal 38 to the audio player 12. Hence, the infrared remote control can be operated in the vicinity of first amplified volume control 24 to remotely control the functions of audio player 12.
The system 10 includes a second amplified volume control 40/ which is identical with first amplified volume control 24 and hence also has an onboard preamplifier and an onboard low powered amplifier (not shown) . Second amplified volume control 40 is wired directly to first amplified volume control 24 by means of 8 conductor twisted pair cable 42, so that first amplified volume control 24 can provide audio signals to second amplified volume control 40. In the arrangement shown in figure 1, second amplified volume control 40 is not provided with an external amplifier; instead, the onboard amplifier of second amplified volume control 40 is switched on and the output of that onboard amplifier is connected to a further set of speakers 44. As second amplified volume control 40 is identical with first amplified volume control 24, the
aforementioned infrared remote control can be used to control audio player 12 also; second amplified volume control 40 can detect infrared signals (i.e. from a remote control) , convert them into electrical signals, and transmit those signals along cable 42 to the first amplified volume control 24 and from there - as described above - to input module 14.
It will be understood that system 10 may include further identical amplified volume controls of essentially unlimited number.
The system 10 includes a power supply 46 that powers first and second amplified volume controls 24,40 via power cables 48. Power cables 48 may run alongside the audio/infrared cable 42, depending on the location of power supply 46.
A distributed audio system according to another embodiment of the present invention is shown generally at 50 in figure 2. Some features of system 50 are essentially identical with features of system 10, so like reference numerals have been used to identify like features. System 50 includes multiple audio players 52a, 52b (of which there could be an essentially unlimited number) , a multi-input amplifier 54 connected thereto and - as in the embodiment of figure 1 - a wall mounted input module 14 (connected to the unbalanced output 56 of amplifier by electrical cables 58) . The input module 14 has a wall plate 20 and RCA input jacks 22, and converts the unbalanced signal from amplifier 54 to a balanced signal.
The input module 14 is wired to first amplified volume control 24 via 8 conductor twisted pair cable 26. Infrared signals received - and converted to electrical signals - by first amplified volume control 24 are also sent in cable 26 from first amplified volume control 24 to
the infrared output 34 of the input module 14, so that an infrared remote control at first amplified volume control 24 can remotely operate the functions of the amplifier 54 and audio players 52a, 52b. The onboard amplifier of first amplified volume control 24 is turned off and an external amplifier 28 is connected to the onboard preamplifier of first amplified volume control 24. External amplifier 28 is powered either through a remote or a local power source, as in system 10 of figure 1. The first amplified volume control 24 operates as a preamplifier to drive the external amplifier 28, while external amplifier 28 drives the set of speakers 30. Second amplified volume control 40 is wired directly from first amplified volume control 24 via 8 conductor twisted pair cable 42 to transmit audio signals to the second amplified volume control 40 (and λ infrared' control signals from amplified volume control 40 to first amplified volume control 24) • The onboard low powered amplifier of second amplified volume control 40 is wired directly to a further set of speakers 44. The system 50 includes a power supply 46 that powers first and second amplified volume controls 24,40 via power cables 48.
A distributed audio system according to a further embodiment of the present invention is shown generally at 70 in figure 3. System 70 is almost identical with system 50 of figure 2, so like reference numerals have been used to identify like features. However, unlike wall mounted input module 14 of the embodiments of figures 1 and 2, system 70 has volume controls that are wired in a so- called 'star' topology in which input module 14' is directly wired to both first and second amplified volume controls 24,40 via respective 8 conductor twisted pair cables 26,42' (unlike in systems 10 and 50, where input module 14 is connected to first amplified volume control 24 which is then connected to second amplified volume control 40) .
Figure 4 is a schematic circuit diagram of an amplified volume control 80, of the type shown at 24 and 40 in figures 1 to 3, so like features have been identified by like reference numerals. Amplified volume control 80 is depicted with external amplifier 28, speakers 30 and further speakers 44. The amplified volume control 80 has a power input/output 82 (comprising a power output looped to a power input) , for receiving power and - should the amplified volume control 80 be operated with another comparable amplified volume control (such as is first amplified volume control 24 to second amplified volume control 40 in figures 1 and 2) - for powering the further amplified volume control by means of a power cable (cf . power cable 48 of figures 1 and 2) .
Amplified volume control 80 has signal I/O terminals 84 (for connection via eight conductor twisted pair cable to input module 14) comprising infrared terminals 86i, left audio-in terminals 861 and right audio-in terminals 86r.
In case it is desired to connect amplified volume control 80 to another comparable amplified volume control, amplified volume control 80 includes infrared terminals 88i, left audio-out terminals 881 and right audio-out terminals 88r, arranged to receive from signal I/O terminals 84 the signals input at signal I/O terminals 84. Such cascading of a plurality of amplified volume controls is also facilitated by the use of separate power and signal cables (power cables 48 and signal cables 26,42,42' respectively) , as these embodiments can readily be equipped with power cables 48 that can carry sufficient power for any likely number of amplified volume controls. (Some background art systems employ a combined power/signal cable, such as a category 5 four pair twisted cable, which would limit the power that can be transmitted and hence any such cascading.)
I/O terminals 84 are connected to a preamplifier 90, whose output is input into control circuitry 92. The output of control circuitry 92 is connected to an onboard switch 94. Onboard switch 94 has three settings: in a first setting (that depicted in this figure) the output of the preamplifier is directed to a 6 W onboard amplifier 96, the output of which is directed to first output 98. It will be appreciated by those in the art that onboard amplifier 96 may have other power outputs, according to intended application. For example, a 12 W onboard amplifier will be suitable for many domestic entertainment applications. In a second setting of switch 94, the output of the preamplifier 90 is directed to a second output 100 (i.e. bypassing onboard amplifier 96). In a third setting of switch 94, the output of the preamplifier 90 is directed to both onboard amplifier 96 (and thence first output 98) and second output 100.
First output 98 of amplified volume control 80 is in the form of audio outputs for direct connection to a set of speakers (such as speakers 44 of figures 1 to 3) .
Second output 100 is provided for those circumstances where higher fidelity sound is desired. For this reason, second output 100 comprises left and right output terminals, to which can be connected - by a suitable cable - a remotely located, high powered external amplifier 28 (the output of which is connected to a set of speakers, such as speakers 30 of figures 1 to 3) . This external amplifier 28 is controlled by preamplifier 90 via control circuitry 92. During this mode of operation (i.e. with switch 94 in its second setting) , onboard amplifier 96 can be switched off.
It may also be desired to operate both amplifiers (i.e. external amplifier 28 and onboard amplifier 96) simultaneously, and this is accomplished by means of the
third setting of switch 94.
The control circuitry 92 of amplified volume control 80 has a control output 102 for providing an on/off or standby control signal for the external amplifier 28.
Amplified volume control 80 also includes infrared sensor 104 for receiving infrared control signals from an infrared remote control (not shown) , and infrared circuitry 106 for receiving the output of the infrared sensor 104, and passing those signals to signal I/O terminals 84 and control circuitry 92.
Amplified volume control 80 includes an external volume control in the form of a pair of buttons (not shown) , one to increase volume, the other to decrease volume, by means of which a user can control the volume of the ultimate audio output. This external volume control is connected to the control circuitry 92, so can be used to control control circuitry 92 to change the amplitude of the signal output by preamplifier 90. The volume can also be adjusted by means of the infrared remote control mentioned above, as infrared circuitry 106 is also connected to control circuitry 92.
In use, audio signals received at signal I/O terminals 84 are transmitted to preamplifier 90, and thence to control circuitry 92. From the control circuitry 92, the signals enter onboard switch 94 that - as described above - passes the signals to the onboard amplifier 96 or, bypassing the onboard amplifier, to second output 100 (for connection to external amplifier 28) , or to both the onboard amplifier 96 and second output 100.
Figure 5 is a schematic circuit diagram of an alternative amplified volume control 110, of the type shown at 24 and 40 in figures 1 to 3, according to another embodiment of the present invention. Amplified volume control 110 is
identical in most respects with amplified volume control 80 of figure 4, so like features have been identified by like reference numerals. However, rather than having the first output and second output as distinct outputs, in amplified volume control 110 they are provided as a combined output 112. This may be suitable for those applications in which the cables used to couple combined output 112 to speakers or to an external amplifier can be accommodated by the same set of terminals; alternatively, an adaptor connector can be added to modify combined output 112 from having, for example, RCA terminals (for connection to an external amplifier) to, for example, speaker binding posts (for connection to a set of speakers) .
Figure 6 is a schematic circuit diagram of an amplified volume control 120 according to an alternative embodiment of the present invention, for the distributed audio systems of figures 1 to 3 , depicted with external amplifier 28, speakers 30 and further speakers 44.
Amplified volume control 120 is similar to amplified volume control 80 of figure 4, so like reference numerals have been used to indicate like features. However, unlike amplified volume control 80, amplified volume control 120 includes additional lines 122, 124 that connect infrared terminals 88i, left audio-out terminals 881 and right audio-out terminals 88r to second output 100 (hence bypassing onboard amplifier 96 of amplified volume control 120) . Looping second terminals 100 ultimately off I/O terminals 84 in this manner means that the signal is always available to external amplifier 28.
Amplified volume control 120 includes an onboard switch 94', which differs somewhat from onboard switch 94 of amplified volume control 80. Onboard switch 94' of amplified volume control 120 has only two settings, "on" and XΛoff", as onboard switch 94' controls only whether a
signal is passed to onboard amplifier 96. Hence, in the "on" setting (depicted in this figure) the output of the preamplifier is directed to onboard amplifier 96, the output of which is coupled to first output 98. In the "off" setting the output of the preamplifier is not directed to onboard amplifier 96, so no output is provided at first output 98. Owing to additional lines 122, 124, however, in both settings the input signal is available at second output 100.
As in amplified volume control 80, control circuitry 92 provides control signals for controlling the volume of the output. In particular, control circuit 92 of amplified volume control 120 is configured to send additional control signals to external amplifier 28 - via control output 102 - comprising either a negative signal (for "volume up") or a positive signal (for "volume down") ; these signals can be used to effectively switch external amplifier 28 off, whether external amplifier 28 is being used exclusively or so that - if onboard switch 94' is in its "on" setting - first output 98 can be used exclusively. Hence, control circuit 92 can then - according to the setting of the volume signal - control devices connected to first output 98, to external amplifier 28, or to first output 98 and external amplifier 28.
Amplified volume controls 80, 110 and 120 can be sued with analogue or digital input signals. If for use with digital input signals, volume controls 80, 110 and 120 include a digital to analogue converter (not shown in figures 4 to 6) , and provide analogue output signals at both first output 98 and second output 100 (or combined output 112) . Amplified volume control 120 may, alternatively, buffer the digital input signals received at the second set of terminals (i.e. infrared terminals 88i, left audio-out terminals 882 and right audio-out
terminals 88r) , and forwarded to second output 100 for transmission in digital form to external amplifier 28, which would then perform the digital to analogue conversion.
Modifications within the scope of the invention may be readily effected by those skilled in the art. It is to be understood, therefore, that this invention is not limited to the particular embodiments described by way of example hereinabove.
In the claims that follow and in the preceding description of the invention, except where the context requires otherwise owing to express language or necessary implication, the word "comprise" or variations such as
"comprises" or "comprising" is used in an inclusive sense, that is, to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.
Further, reference herein to prior art is not intended to imply that such prior art forms or formed a part of the common general knowledge.
Claims
1. A volume control apparatus, comprising: an input for receiving input signals; a preamplifier for receiving signals from said input; an onboard amplifier for receiving signals from said preamplifier; a first output for outputting signals from said onboard amplifier; and a second output for outputting signals comprising or derived from said input signals without amplification by said onboard amplifier; wherein output from said second output is suitable for inputting into an external amplifier.
2. An apparatus as claimed in claim 1, wherein said output from said second output comprises an output of said preamplifier .
3. An apparatus as claimed in claim 1, wherein said output from said second output comprises some or all of said input signals .
4. An apparatus as claimed in claim 3, wherein said output from said second output is transmitted to said second output from a looped terminal connected to said input.
5. An apparatus as claimed in claim 1, further comprising a switch with a first setting for directing said output of said preamplifier to said onboard amplifier and a second setting for directing said signals from said preamplifier to said second output.
6. An apparatus as claimed in claim 5, wherein said switch includes a third setting that directs said signals from said preamplifier to both said onboard amplifier and said second output .
7. An apparatus as claimed in claim 1, further comprising a switch with a first setting in which an output of said preamplifier is passed to said onboard amplifier and a second setting in which said output of said preamplifier is not passed to said onboard amplifier.
8. An apparatus as claimed in claim 7, wherein said input signals are be permanently available at said second output .
9. An apparatus as claimed in claim 1, further comprising a control circuit for outputting a control signal adapted to control an external amplifier.
10. An apparatus as claimed in claim 1, wherein said first output and said second output are provided as a combined output, and said apparatus includes a switch with a first setting for directing an output of said preamplifier to said combined output via said onboard amplifier and a second setting for directing said output from said preamplifier to said combined output without passing via said onboard amplifier.
11. An apparatus as claimed in claim 1, further comprising a digital to analogue converter for converting said input signals from digital to analogue input signals, wherein said apparatus is arranged to provide digital output signals at at least said first output.
12. A volume control apparatus, comprising: a digital input for receiving digital input signals; a digital to analogue converter for converting said input signals from digital to analogue input signals; a preamplifier for receiving said digital input signals from said digital to analogue converter and outputting preamplified signals; and an output for outputting an output comprising or derived from said preamplified signals.
13. An apparatus as claimed in claim 12, further comprising an onboard amplifier for receiving said preamplified signals, amplifying said preamplified signals, and outputting amplified signals, wherein said amplified signals is available at said output.
14. An apparatus as claimed in either claim 1 or 12, further comprising a further output connected to said input for outputting said input signals so that said input signals are available at said further output for coupling to a comparable volume control apparatus .
15. An apparatus as claimed in either claim 1 or 12, comprising a power input and a power output coupled to said power input so that a further volume control apparatus can be powered from said apparatus .
16. An apparatus as claimed in either claim 1 or 12, comprising a further signal output looped to said input so that said input signals can be transmitted to a further volume control apparatus .
17. A distributed audio system comprising one or more volume control apparatuses as claimed in any one of the preceding claims .
18. An audio system as claimed in claim 15, including separate audio and power cables .
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2006100238 | 2006-03-28 | ||
| AU2006100238A AU2006100238A4 (en) | 2006-03-28 | 2006-03-28 | Volume control device and distributed audio system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2007109830A1 true WO2007109830A1 (en) | 2007-10-04 |
Family
ID=36406735
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/AU2007/000255 WO2007109830A1 (en) | 2006-03-28 | 2007-03-01 | Volume control device and distributed audio system |
Country Status (2)
| Country | Link |
|---|---|
| AU (1) | AU2006100238A4 (en) |
| WO (1) | WO2007109830A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011077212A1 (en) * | 2009-12-22 | 2011-06-30 | Toyota Jidosha Kabushiki Kaisha | Acoustic apparatus, acoustic system, and audio signal control method |
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| US6389139B1 (en) * | 1997-11-18 | 2002-05-14 | Dana Innovations | Powered volume control for distributed audio system |
| AU2003100201A4 (en) * | 2003-03-19 | 2003-07-17 | Robert Sanders | An Intelligent Distributed Audio System |
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2006
- 2006-03-28 AU AU2006100238A patent/AU2006100238A4/en not_active Ceased
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2007
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| US5243344A (en) * | 1991-05-30 | 1993-09-07 | Koulopoulos Michael A | Digital-to-analog converter--preamplifier apparatus |
| US6389139B1 (en) * | 1997-11-18 | 2002-05-14 | Dana Innovations | Powered volume control for distributed audio system |
| AU2003100201A4 (en) * | 2003-03-19 | 2003-07-17 | Robert Sanders | An Intelligent Distributed Audio System |
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| ANTHEM: "INTEGRATED 2 Integrated Amplifier", PRODUCT OVERVIEW, Retrieved from the Internet <URL:http://www.web.archiver.org/web/20041211074250> * |
| ARCAM: "SOLO Music System", HANDBOOK/MANUAL, Retrieved from the Internet <URL:http://www.web.archiver.org/web/20060327223851> * |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011077212A1 (en) * | 2009-12-22 | 2011-06-30 | Toyota Jidosha Kabushiki Kaisha | Acoustic apparatus, acoustic system, and audio signal control method |
Also Published As
| Publication number | Publication date |
|---|---|
| AU2006100238A4 (en) | 2006-05-04 |
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