Abstract:
A portable binaural recording and playback accessory for a multimedia device includes headphones with embedded outside facing microphones, a protective mobile electronic device case with embedded stereo microphone preamplifier or audio video codec containing a microphone preamplifier, analog to digital converter/digital to analog converter (or digital signal processor), and a battery, allowing for the recording and playback of high quality binaural audio, while at the same time acting as a protective case and as an additional power supply.

Description:
BACKGROUND 
       [0001]    Smart phones and tablet computers have dominated consumer electronic sales in recent times, achieving a dominating presence in the lives of many. People now use their phones or tablet computers to read books, watch movies or television programs, listen to music, make telephone calls, record activities with portable, mountable camera/video recorders, and/or communicate via voice-over-IP with or without video data. Additionally, people are using smart phones and tablet computers for audio and video recording, from simply recording their own thoughts to recording conversations, business meetings, concerts, or education material such as presentations or podcasts. The accessibility and size of smart phones and tablet computers make them a quick and easy audio and video recording option. Unfortunately, recordings on phones will almost always be monophonic, reliant on the quality of the built-in microphone, creating a less than ideal audio recording. 
       SUMMARY OF THE INVENTION 
       [0002]    In accordance with the invention, headphones with embedded microphones connect to a protective mobile electronic device case which contains an audio/video codec and battery, allowing for the recording and playback of high quality binaural audio while at the same time acting as a protective case and as an additional power supply. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]      FIG. 1  is a perspective view of the binaural recording and playback accessory for a multimedia device of the present invention in use with a portable electronic device; 
           [0004]      FIG. 2  is a perspective view of the headphones of the present invention; 
           [0005]      FIG. 3  is an exploded view of the case and portable electronic device of the binaural recording and playback accessory for a multimedia device of the present invention; 
           [0006]      FIG. 4A  is a top view of the case of the binaural recording and playback accessory for a multimedia device of the present invention; 
           [0007]      FIG. 4B  is a right-side view of the case of the binaural recording and playback accessory for a multimedia device of the present invention; 
           [0008]      FIG. 4C  is a left-side case of the binaural recording and playback accessory for a multimedia device of the present invention; 
           [0009]      FIG. 5  is a front view of the case of the binaural recording and playback accessory for a multimedia device of the present invention; 
           [0010]      FIG. 6  is a rear view of the case of the binaural recording and playback accessory for a multimedia device of the present invention 
           [0011]      FIG. 7  is a perspective view of the case of an alternate embodiment binaural recording and playback accessory for a multimedia device of the present invention; 
           [0012]      FIG. 8  is a rear-perspective view of the case of an alternate embodiment binaural recording and playback accessory for a multimedia device of the present invention; and 
           [0013]      FIG. 9  is a diagram illustrating the possible constituent parts of the audio/visual codec of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]      FIG. 1-2  illustrates the binaural recording and playback accessory for a multimedia device  10  of the present invention in use with a multimedia device  12 . Accessory  10  comprises case  14  and headphones  16 . The headphone assembly  16  comprises a right-ear piece  18 , a right headphone speaker  18   b,  a right-ear piece microphone unit  18   a,  a left-ear piece  20 , a left headphone speaker  20   b,  and a left-ear piece microphone unit  20   a.  As illustrated herein headphones  16  are earbud-style headphones; however, circumaural (around-the-ear) audio headphones that are either closed back or open backed could also be used without departing from the scope of the invention (in an openbacked design all ambient sound can still be “passed through” to the user concurrently with the audio playing through the speakers). Microphone units  18   a  and  20   a  are powered via what is known in the industry as “phantom power” (a minute electrical current passing to the microphone units through at least one of the same conductors that carry the microphone&#39;s right and left output signals.) The hard wiring of the headphones  16  in the preferred embodiment would utilize six conductors—three per side. This is possible by utilizing a common negative conductor for both the microphones ( 18   a,    20   a ) and headphone speakers ( 18   b,    20   b ). 
         [0015]    In the preferred embodiment jack  17  is of a tip ring sleeve connector style, which is well known in the art. Jack  17  has two different regions (generally stepped in diameter) and an outer sleeve each connected to one of the three hardwires described above (not illustrated). Should an alternate embodiment have an additional microphone for capturing a user&#39;s talking (not illustrated) a seventh wire from this microphone would be required and the internal wiring for the connection to the jack  17  would be modified as would be well known in the industry. Microphones  18   a,    20   a  are outward facing (face away from the head of the user) and lie along the centerline of the ear canal, when placed in a user&#39;s ear. Microphones  18   a,    20   a  are non-directional, capturing sound from all directions, partially limited only by any physical barriers. Thus, microphones  18   a,    20   a  are positioned to collect the exact same sound that would go into the ear canal as the ear canals would capture without headphones. In this way the sound origin, direction, volume, frequencies, tonal response, etc., as captured by microphones  18   a,    20   a  will most closely approximate the sound collected by the users&#39; ears at the time of a recording, essentially mimicking an Head Related Transfer Function (HRTF). When reproduced, this audio recording will closely mimic the original source (of the audio waves being captured) and coordinate this sound with any video captured from this point (that is the location of the multimedia device  12 ). 
         [0016]    Microphones  18   a,    20   a  are enabled via switch  19  which is mounted on case  14 . A visual indicator  29  of the of the respective input and output levels from the microphones  18   a ,  20   a,  is also located on case  14  and may comprise a series of LEDs. Recording level control is accomplished via a two-way switch  31 , allowing the user to raise or lower the recording level. The switch  31  will be mounted in the case adjacent the visual indicator  29 . Since the separate microphones face 180 degrees apart and are blocked by the mass of a human head not all sounds recorded by the microphones will have the same volume. The lower of the two recorded signal volumes must be detected in order to be recorded. Additionally the higher of the two signals must be maintained below a maximum level for clarity. Switch  31  will allow both microphone sensitivities to be simultaneously adjusted upward or downward so as to insure a proper recording level is maintained as well as the stereo separation of the recorded signals. Although illustrated as wired, headphones  16 , and hence microphones  18   a,    20 , could easily be enabled for wireless transmission such as Wi-Fi, Bluetooth, 4G including LTE, Wibro Evolution (3.9G), LTE-Advanced, or otherwise enabled for wireless transmission of audio signals. 
         [0017]    Case  14  contains one or more batteries  22  which can be directed to serve as the primary power or reserve power for the multimedia device  12 . In an alternate embodiment batteries  22  may also be directed to serve as the primary power source for the codec  26  and the headphones  16 . Switch  24  allows the user to select the desired battery function. Case  14  can be water resistant or even completely waterproof. 
         [0018]    Headphone jack input hole  28  is incorporated into case  14  and is adapted to receive headphone jack  17  and is matingly conformed for proper electrical connection with the various six (or seven) conductors of the aforementioned jack  17 . Input hole  28  moves electronic signals both ways—by reception and transmission. Transmission in the cases of sound/music being played through the headphones  16  and the phantom power being sent to the microphone units  18   a  and  20   a  and reception when microphones  18   a,    20   a  are recording. Case  14  connects to multimedia device  12  via a male multi-pin interface connector  23  that matingly conforms to a female multi-pin interface connector  25  incorporated into the multimedia device  12  and that allows electrical continuity between the multimedia device  12 &#39;s electronic features, the codec  26 , and the headphones  16 . It should be noted that male multi-pin interface connector  23  could vary in positioning within case  14  and size, depending on “style” of the female multi-pin connector  25  of the multi-media device to which it connects. Additionally, headphones  16  could easily be replaced by using an adaptor (connected to case  14  via input hole  28 ) to connect two external microphones of any type. 
         [0019]    There is a series of hard wires imbedded between the male multi-pin interface connector  23 , the codec  26  and the headphones  16 . It is to be noted that input hole  28  in case  14  is hard wired for electrical contact to both the codec  26  and the male multi-pin interface connector  23 . This allows a plethora of different operations. It is to be noted that the headphone jack input hole of the multimedia device  12  is not utilized with assembly  10 , rather it is replaced with the headphone jack input hole  28  which is wired to the codec  26  and the male multi-pin interface connector. If the multimedia device&#39;s headphone jack input hole was used, then there would be no way to route any of the microphones output to codec  26  for processing. In this way the input signal from the microphones  18   a,    20   a  is processed first by codec  26  prior to being transmitted to device  12 , while the output signal from device  12  passes through codec  26  prior to being transmitted to headphones  16 . 
         [0020]    As used herein “codec” is hardware, firmware, software, or a combination of hardware, firmware, and software that provides the architecture, which is configurable into a number of functional arrangements to accomplish the audio and video processing necessary for accessory  10 . As illustrated in  FIG. 9 , codec  26  may include microphone inputs, microphone amplifiers, analog to digital audio convertor, audio to digital signal processor, video digital processor, digital to analog audio convertor. However, in its most basic form codec  26  employs only a microphone preamp  40  to digital audio convertor  42 . 
         [0021]    Case  14  may include two embedded cameras  50 ,  52  adapted for stereoscopic video recording. In such an embodiment codec  26  would receive the two separate video signals from the cameras  50 ,  52  and process them appropriately for enhanced stereoscopic recording and playback via multimedia device  12 . In this embodiment the initiation of a video recording by multimedia device  12  would not operate the local camera (that is the camera in device  12 ) but rather initiate operation and substitute the output of cameras  50 ,  52  into the multimedia device  12 . 
         [0022]      FIGS. 7 &amp; 8  illustrate an alternate embodiment of case  14  wherein embedded microphones  60  into the sides and ends of case  14 . This embodiment allows for headphone  16 /microphones  18   a,    18   b  to be omitted. The user would only require case  14  to produce high quality recordings, and no headphones or external microphones would be needed. Embedded microphones  60  could be located on opposing sides of case  14 , at opposing ends of case  14 , or on the back of case  14 , and codec  26  could choose which pair of microphones  60  to employ for recording (or use both pairs) depending on the orientation of the phone. Additionally, digital signal processing could be added to individual microphones  60  to enhance the recording effect. The digital signal processing could include filtering, dynamic delay, mid side decode, variable phase inversion, compression, limiting, beam-forming, 
         [0023]    HRTF filters, or any other digital signal processing technology. Microphones  60  are also visible in previous embodiments. It should be noted that microphones  60  can be embedded anywhere on case  14  without departing from the scope of the invention. 
         [0024]    In operation, (playing headphones only) the digital audio output signal from the multimedia device  12  passes through the male and female pin connectors ( 23 ,  25 ) and is routed via hard wires to the codec&#39;s  26  digital/analog converter  44  where it is converted to an analog signal, and with no further processing required, routes the audio signals via the tip ring sleeve connector style jack  17  through input jack input hole  28 , which then sends a positive and negative left and right signal to the headphones  16 . 
         [0025]    In a final embodiment codec  26  may amplify and process signals from both microphones  18   a,    20   a,  bypass the analog/digital convertor and directly output their analog audio signal to speakers  18   b,    20   b  in conjunction with audio signals from device  12  that it has converted from digital to analog and also simultaneously provided to the headphones  16 . This feature is especially useful to individuals that are hearing impaired. 
         [0026]    In operation (recording stereo sound only) when sound that is captured by microphones  18   a,    20   a  the analog input signal travels via jack  17  through input hole  28  to codec  26  where preamp  40  amplifies the signal. Next analog/digital convertor converts the analog signal to digital and the now digital signal passes through the male connector  23  to female connector  25  into multimedia device  12  for recording. Codec  26  can optionally employ a digital signal processor  43  for additional processing. 
         [0027]    In operation, (recording stereo sound synchronized with video recording) the multimedia device&#39;s video recording feature is deployed from the interface screen on the multimedia device which signals the internal camera to begin recording simultaneously with the initiation of a “record now” signal to the multimedia devices internal mono microphone. Since the microphones are electrically connected to the codec (pre amp, optional amp, digital signal processor and analog to digital converter) and the codec is connected to the multimedia device through the male and female pin connectors, the multimedia device&#39;s logic controller (internal microprocessor) recognizes the existence of a connected, alternate set of stereo microphones (the default as stereo always trumps mono in the hierarchy of recording) and restricts the use of the mono microphone. The “record now” signal is routed through the male and female multi pin interface connector through the codec to the microphones to begin recording. Phantom power is initiated to the microphones. The microphone&#39;s output signal passes through the tip ring sleeve connector style jack  17  and the headphone jack input hole  28  then via the hard wires to the codec where it sequentially passes through the pre amplifier, the digital signal processor and the digital/analog convertor. Eventually, after sound processing, a set of left and right digital audio signals are set via hard wires to the male and female multi pin interface connector and into the multimedia device&#39;s digital memory where it is stored in synchronization with the video images. 
         [0028]    The forgoing description is meant to be exemplary only and should not be deemed limiting. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.