HK40042200A - Bluetooth speaker configured to produce sound as well as simultaneously act as both sink and source - Google Patents

Description

Bluetooth speaker configured to produce sound and to act as both a receiver and a source

Related application (claiming priority)

This application claims the benefit of U.S. provisional application No.62/703,319 filed on 25/7/2018, the contents of which are incorporated herein by reference in their entirety.

Technical Field

The present invention relates generally to wireless speakers, and more particularly to bluetooth speakers, such as subwoofer (subwoofer), configured to receive bluetooth signals, output sound, and connect to an audio system, such as another bluetooth speaker or an audio system of a vehicle, via bluetooth.

Background

Personal audio is an important growing market, driven primarily by the ease of use and portability of bluetooth speakers, to which users can stream audio from mobile phones. In most cases, these portable bluetooth speakers do not provide enough bass frequencies to provide a more "full" sound quality to the user, as do home theater systems with subwoofers.

Portable bluetooth speakers generally have difficulty providing low frequencies (20-200Hz) at the same level as mid to high frequencies (200-20 kHz). This is mainly due to the size of the loudspeaker, which cannot move the necessary amount of air to generate low frequencies (20-200Hz) in this range. Another reason is the size of the portable bluetooth speaker. In order to produce the same level of sound as the medium-high frequencies, the loudspeakers inside the device require a larger size housing, which may greatly increase the original size and weight.

Many OEM car stereos currently on the market offer bluetooth connectivity as a standard option. Subwoofers are not a common standard option for stereo systems, so low frequency output levels are not optimal for "full sound". It is believed that the automotive manufacturer would not offer subwoofers as a standard option because subwoofers add cost, weight, and space requirements to the overall vehicle design.

After-market solutions can be used to supplement car stereos, where the consumer must install a subwoofer himself or use professional services, as it is often necessary to remove certain parts of the car to enable wiring and installation of third party electronics such as amplifiers. For many car owners, they do not have experience or knowledge of installing after-market electronics, or do not want to pay a high installation fee. In most cases of renting cars, operating the car with after-market electronics will violate the rental agreement.

Existing solutions can connect multiple wireless speakers for audio playback, including subwoofers, but they can only be used by the same manufacturer specifically designed for this purpose. As an example, these products cannot connect to competitor's products.

Existing subwoofers are not considered to be "portable" nor so designed. Subwoofers are generally too heavy and large to be portable. In addition, subwoofers are powered by ac outlets or, in automobiles, receive 12-16V via hard wiring.

There is a need to provide better bass for audio systems that are portable, battery powered, and easily connectable to existing third party bluetooth audio systems. Users of this technology will be able to pair this subwoofer device with their existing bluetooth speakers, their bluetooth enabled car audio system, or any other bluetooth audio system without professional installation.

Disclosure of Invention

It is an object of embodiments of the present invention to provide a bluetooth speaker, such as a subwoofer, configured to receive a bluetooth signal, generate sound, and connect to an audio system, such as a bluetooth speaker, a vehicle audio system, a home theater system, or a smart television, via bluetooth.

It is a further object of embodiments of the invention to provide a device that can receive bluetooth signals, e.g. from a smartphone or other device, play sound through at least one speaker of the device, and wirelessly transmit signals to an audio system, e.g. another speaker or the audio system of a vehicle, through bluetooth.

Briefly, an embodiment of the present invention provides an apparatus comprising a bluetooth signal receiver, a signal processor, at least one speaker, and a bluetooth signal transmitter. The device is configured to receive a bluetooth signal using a bluetooth signal receiver, process the signal using a signal processor, emit sound using at least one speaker, and transmit the bluetooth signal using a bluetooth signal transmitter.

A preferred embodiment of the present invention comprises a portable, battery-powered bluetooth subwoofer, comprising: a Bluetooth signal receiver configured to receive a wireless Bluetooth signal; a signal processor configured to receive a digital audio signal from the Bluetooth signal receiver; a Bluetooth signal transmitter configured to receive a signal from the signal processor and wirelessly transmit a Bluetooth signal; a digital audio buffer configured to receive a signal from the signal processor; at least one microphone; a synchronization circuit configured to receive signals from the at least one microphone and the digital audio buffer; and an amplifier, the digital audio buffer configured to receive the signal from the synchronization circuit and provide a signal to the amplifier, the amplifier configured to drive the at least one speaker to produce sound. At least one user interaction control, adjustable by a user, connected to the signal processor may be provided.

Drawings

The invention, both as to organization and manner of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in conjunction with the accompanying drawings, wherein like reference numerals identify like elements, in which:

FIG. 1 is a block diagram of a portable, battery-powered Bluetooth sub-woofer in accordance with a preferred embodiment of the present invention;

FIG. 2 depicts a standard method of connecting a mobile phone to a Bluetooth speaker;

FIG. 3 is similar to FIG. 2, depicting the device of FIG. 1 for the same application;

FIG. 4 depicts a standard method of connecting a mobile phone to a Bluetooth enabled car stereo (also known as a "stereo host");

FIG. 5 is similar to FIG. 4, depicting the device of FIG. 1 for the same application;

FIG. 6 is a diagram of cross-correlation calculations for calibration (or synchronization) of audio signals; and is

Fig. 7 shows cross-correlation calculations not used for synchronizing audio signals.

Detailed Description

While this invention is susceptible of embodiment in different forms, there is shown in the drawings and will herein be described in detail specific embodiments for the purpose of understanding the present disclosure, which are to be considered as illustrative of the principles of the invention and not intended to limit the invention to the embodiments illustrated.

Fig. 1 is a block diagram of a device configured to receive a wireless signal, generate sound, and wirelessly connect to an audio system, such as another speaker or an audio system of a vehicle, particularly illustrating a preferred embodiment of the present invention, wherein the device includes a portable, battery-powered bluetooth subwoofer 10 according to the preferred embodiment of the present invention.

As shown, the portable, battery-powered Bluetooth sub-woofer 10 includes at least one wireless receiver, such as a Bluetooth signal receiver 12. The bluetooth signal receiver 12 is configured to receive wireless signals, such as bluetooth signals, from the mobile phone. Thus, for example, music may be wirelessly transmitted from a mobile phone to subwoofer 10. Subwoofer 10 includes a signal processor 14, such as a Digital Signal Processor (DSP), configured to receive a digital audio signal 16 from bluetooth signal receiver 12. The subwoofer 10 also includes at least one wireless source, such as a bluetooth signal transmitter 18, configured to receive the signal 20 from the signal processor 14 and wirelessly transmit a bluetooth signal to an audio system, such as another speaker (as shown in fig. 3 and described more fully below) or an audio system of a vehicle (as shown in fig. 5 and described more fully below).

As shown in fig. 1, subwoofer 10 also preferably includes: a digital audio buffer 22 configured to receive a signal 23 from the signal processor 14; at least one microphone 24; and a synchronization circuit 26 configured to receive a signal 28 from the at least one microphone 24 and a signal 30 from the digital audio buffer 22. An amplifier 32 is preferably provided and the digital audio buffer 22 is configured to receive a signal 34 from the synchronization circuit 26, provide a signal 36 to the amplifier 32, and the amplifier 32 is configured to drive at least one speaker 38 to produce sound.

As shown in fig. 1, at least one user interaction control, such as one or more knobs and/or switches 40, may be provided for connection to the signal processor 14, wherein the at least one user interaction control is adjustable by a user, such as setting a crossover frequency, phase, etc., wherein the controls are user adjustments common in subwoofer applications. In addition, the portable, battery-powered Bluetooth sub-woofer 10 may include one or more inputs, lights, buttons, etc., which are standard in the industry and therefore have been omitted from the drawings for clarity.

Preferably, the signal processor 14 is configured to effectively feed low frequencies to the digital audio buffer 22 for eventual output via the at least one speaker 38, and to feed medium and high frequencies to the bluetooth signal transmitter 18, the bluetooth signal transmitter 18 being paired with another audio system, such as another speaker (as shown in fig. 3, described more fully below) or an audio system of the vehicle (as shown in fig. 5, described more fully below) that plays medium and high frequencies.

In any event, to calibrate (or synchronize) the low frequencies of another audio system, subwoofer 10 is preferably configured to use at least one microphone 24, which microphone 24 feeds signal 28 back to synchronization circuit 26. The synchronization circuit 26 is configured to determine the total delay and to point to a memory address in the digital audio buffer 22 in relation to the low frequency digital audio signal 23 matching the incoming audio received via the microphone 24. The signal 36 is then fed to the amplifier 32 for playback through at least one speaker 38. Preferably, the subwoofer 10 is configured such that the total delay accuracy is acceptable, e.g., less than 5 milliseconds.

The calibration (or synchronization) is preferably done in a synchronization circuit 26, which synchronization circuit 26 comprises a digital circuit, a programmed field programmable gate array or a programmed digital signal processor, which cross-correlates (cross correlation) the signal 28 from the at least one microphone 24 with the signal 23 delayed by a signal 30. Cross-correlation is a well-studied and well-documented mathematical algorithm. Depending on the particular implementation of synchronization circuit 26, a mathematically equivalent technique such as convolution by applying a finite impulse response filter with programmable coefficients may be required. The calculated number of samples (time) position of the cross-correlation peak with sufficient confidence (in fig. 6, the "X" at 90 is delayed relative to the "0" at 91) is used to control the digital audio buffer 22 to delay the signal 36 to the amplifier and the signal to the line output 80 as needed.

Preferably, the confidence in the calibration is calculated by comparing the "Y" value in the cross-correlation peaks 90 and 93 in fig. 6 and 7, respectively, with the "Y" value in the next highest peaks 92 and 94, and also comparing the Y peak value with the Y mean of the cross-correlation to be evaluated. If the peak is sufficiently greater than the next highest peak, and also sufficiently greater than the average, as shown in FIG. 6, then the delay may be configured using this calculation. If the peak is not sufficiently larger than the next highest peak, or not sufficiently larger than the average, fig. 7 shows both cases, meaning that the result is erroneous, discarded and the calculation repeated.

Preferably, the accuracy of the calibration is improved by delaying the signal 23, resulting in a more useful signal 30 for cross-correlation comparison with the signal 28. The delay may be 0, fixed, or calculated from previous calibration attempts.

Preferably, the accuracy of the calibration is also improved by filtering the signals 28 and 30 according to those frequencies that can be easily detected by the at least one microphone 24, which are considered to be easily reproduced by the speakers receiving the signals from the transmitters 18 and 48, and which are not reproduced by the speaker 38 or (say) 82.

Preferably, the subwoofer 10 is configured to be battery powered and, therefore, as shown in fig. 1, includes a battery 42, associated internal power management circuitry 44, and the subwoofer 10 is configured to be charged using an external wall charger 46. Of course, the subwoofer 10 may alternatively (or additionally) be configured to be hardwired, such as to the power system of an automobile.

Instead of a single bluetooth transmitter 18, a further bluetooth transmitter (represented by point 48 in fig. 1) may be provided to receive the signal 49 from the signal processor 14, thereby configuring the subwoofer 10 to connect (and transmit) to multiple bluetooth speakers simultaneously, e.g., creating a 5.1 surround sound system.

Instead of or in addition to providing signal 36 to amplifier 32 to drive speaker 38, digital audio buffer 22 may provide a signal to line output 80, and line output 80 may be connected to an external active speaker 82, such as an energized external subwoofer or an amplifier connected to a passive subwoofer. In practice, amplifier 32 and speaker 38 may be omitted entirely from device 10, with only line output 80 being provided. Alternatively, or in addition, an amplifier 83 may be provided within the device 10 to provide a stimulus output to an amplifier output 85, the amplifier output 85 being connectable to an external passive loudspeaker 87, such as a passive loudspeaker or subwoofer. Any one or more of these alternatives, namely internal amplifier 32 and speaker 38, line output 80, internal amplifier 83, and amplifier output 85 may be implemented.

Another embodiment may provide more than one microphone 24, as represented by the multiple points indicated by reference numeral 25, in order to provide improved noise cancellation.

Portable subwoofer 10 is configured to connect to any bluetooth device capable of streaming audio. Common examples include mobile phones, tablets, personal computers, and the like. In this disclosure, a mobile phone is used as an example only.

Fig. 2 depicts a standard method of connecting a mobile phone 50 to a conventional bluetooth speaker 60. The mobile phone 50 is considered the "source" and the bluetooth speaker 60 is considered the "receiver". Audio data is streamed from the mobile phone 50 to the bluetooth speaker 60. The bluetooth speaker 60 receives the signal, processes it, and amplifies the signal to the speaker, thereby producing audio sounds.

Fig. 3 shows the same solution using the portable subwoofer 10 shown in fig. 1 and described above. As shown in fig. 3, mobile phone 50 is connected to portable subwoofer 10 as a "source" via bluetooth. The portable subwoofer 10 is the "receiver" of the mobile phone 60 and is also the "source" of the bluetooth speaker 60. The bluetooth speaker 60 is a "receiver" relative to the portable subwoofer 10. In essence, the portable subwoofer 10 is configured to receive an audio signal from the mobile phone 50, process the signal, route low frequencies to the internal amplifier 32 (see fig. 1), the amplifier 32 excites the internal subwoofer loudspeaker 38 (see fig. 1), and routes medium and high frequencies to the "source" portion, which is then effectively broadcast to the bluetooth speaker 60 (see fig. 3). Both the portable subwoofer 10 and the bluetooth speaker 60 are synchronized (i.e., using at least one microphone 24 and synchronization circuit 26 as shown in fig. 1) so that the sound is emitted without audible delay.

When paired with portable bluetooth speaker 60, portable subwoofer 10 must be within range of source mobile phone 50 and bluetooth speaker 60. The user will then pair mobile phone 50 with portable subwoofer 10 via bluetooth. The portable subwoofer 10 will be paired with the bluetooth speaker 60 and once connected, the user will stream audio through his mobile phone 50.

The portable subwoofer 10 can be configured to use a level 2 bluetooth power level, which is the most common level of bluetooth audio products today. Its range is typically about ten meters or thirty-two feet. Alternatively, the portable subwoofer 10 can be configured to operate at other levels, such as a level 1 bluetooth power level.

Fig. 4 depicts a standard method of connecting a mobile phone 50 to a conventional bluetooth enabled car stereo (also referred to as a "stereo host") 70. Mobile phone 50 is considered the "source" and head unit 70 is considered the "receiver". Audio data is streamed from the mobile phone 50 to the head unit 70. The head unit 70 receives the signal, processes it, and amplifies it to a speaker 72 in the vehicle, thereby producing audio sound.

Fig. 5 shows the same solution using the portable subwoofer 10 shown in fig. 1 and described above. As shown in fig. 5, mobile phone 50 is connected to portable subwoofer 10 as a "source" via bluetooth. Portable subwoofer 10 is the "receiver" of mobile phone 50 and is the "source" of car stereo (i.e., head unit) 70. The main audio body 70 is a "receiver" relative to the portable subwoofer 10. In essence, the portable subwoofer 10 is configured to receive an audio signal from the mobile phone 50, process the signal, route low frequencies to an internal amplifier (32 in fig. 1) that excites an internal subwoofer loudspeaker (38 in fig. 1), and route medium and high frequencies to a "source" portion, which is then effectively broadcast to the head unit 70. Both the portable subwoofer 10 and the main stereo 70 are synchronized (i.e., using at least one microphone 24 and synchronization circuit 26 as shown in fig. 1) so that the sound is produced without audible delay.

When paired with car stereo 70, portable subwoofer 10 will be positioned within range of source mobile phone 50 and car stereo 70. The user will pair mobile phone 50 with portable subwoofer 10 via bluetooth and portable subwoofer 10 will pair with car stereo 70. Once connected, the user will stream audio through their mobile phone.

The portable subwoofer 10 preferably has features similar to existing subwoofers in order to "adjust" the sound level to match the environment or product with which it is paired. This preferably includes, for example, volume level, crossover frequency and phase.

The portable subwoofer 10 is also configured to synchronize sound with other audio devices (portable bluetooth speakers, car stereo, etc.) so the user will hear music without any delay between the low frequencies from the portable subwoofer 10 and the mid/high frequencies from the other audio devices.

The portable subwoofer 10 is configured to pair with any bluetooth enabled device via bluetooth and act as a "receiver". The portable subwoofer 10 is also configured to pair with other audio devices capable of transmitting bluetooth audio via bluetooth and act as a "source".

The portable subwoofer 10 is also preferably configured to filter the audio signal output to "split" the signal into two streams. One of which is low frequency to the portable subwoofer 10 and the other of which streams wirelessly to another device intended for medium to high frequencies.

The portable subwoofer 10 is also preferably configured to synchronize the audio signals to the portable subwoofer 10 and the unit playing the medium/high frequency so that the user does not hear a delay between the two units playing the audio stream.

Preferably, the portable subwoofer 10 is configured to be portable, small enough to be carried by a person, and portable, operating with rechargeable batteries inside the unit, thus not requiring any other power source, such as an ac outlet or a car power system.

To enhance existing audio systems that do not have sufficient bass, such as portable bluetooth speakers and car stereos without subwoofers, the portable subwoofer 10 can accomplish this with the following capabilities: pairing with a device capable of streaming bluetooth audio, such as a mobile phone, splits the audio so that the portable subwoofer 10 produces a larger bass sound and transmits mid/high frequencies to the existing audio system to produce a fuller sound. Its portability is not only in size and weight, but also because the unit is battery powered, it can operate without requiring an ac outlet or direct car power.

Although the present disclosure refers to bluetooth as the wireless communication standard used by the devices and systems disclosed herein, the devices and related systems may be configured to receive and transmit data using other standards and frequencies, such as future standards, while still falling largely within the scope of the present invention.

Furthermore, although the apparatus has been described as a subwoofer, the apparatus may be provided as, for example, a full range speaker capable of producing low, high and mid frequencies. As such, the "at least one speaker" 38 disclosed herein may actually be a plurality of speakers, e.g., three speakers, with the signal processor 14 configured to transmit different frequencies to different amplifiers associated with different speakers.

While the foregoing description emphasizes bluetooth, it is to be understood that the present invention is not limited to this wireless standard, but may be configured to work with other wireless standards

While particular embodiments of the present invention have been shown and described, it is envisioned that those skilled in the art may devise various modifications without departing from the spirit and scope of the present invention.

Claims (16)

1. A portable device, comprising: a wireless receiver; a signal processor; a wireless source; at least one microphone configured to receive audio from outside the portable device; and at least one of at least one speaker and a line output, wherein the device is configured to receive wireless signals using the wireless receiver, process the signals using the signal processor, and transmit wireless signals using the wireless source in accordance with audio received from the at least one microphone, and wherein the portable device is configured to emit sound using the at least one speaker and/or provide signals to the line output in accordance with audio received from the at least one microphone.

2. The portable device of claim 1, wherein the wireless receiver comprises a wireless signal receiver.

3. The portable device of claim 1, wherein the wireless receiver comprises a bluetooth signal receiver.

4. The portable device of claim 1, wherein the wireless source comprises a wireless signal transmitter.

5. The portable device of claim 1, wherein the wireless source comprises a bluetooth signal transmitter.

6. The portable device of claim 1, further comprising: a digital audio buffer configured to receive a signal from the signal processor.

7. The portable device of claim 6, further comprising: a synchronization circuit configured to receive signals from both the at least one microphone and the digital audio buffer.

8. The portable device of claim 1, further comprising: a digital audio buffer configured to receive a signal from the signal processor, further comprising: a synchronization circuit configured to receive signals from both the at least one microphone and the digital audio buffer, further comprising an amplifier, wherein the digital audio buffer is configured to receive signals from the synchronization circuit and provide signals to the amplifier, the amplifier configured to drive the at least one speaker to produce sound.

9. The portable device of claim 8, wherein the synchronization circuit is configured to employ cross-correlation to effect calibration of the device.

10. The portable device of claim 9, wherein the portable device is configured to add a delay if, after comparing the peaks of the cross-correlation of the signals received by the synchronization circuit, it is determined that the highest peak is substantially greater than the next highest peak and also substantially greater than the average of the cross-correlation of the signals received by the synchronization circuit.

11. The portable device of claim 10, wherein the portable device is configured to not add delay but repeat the calculation if it is determined that the highest peak of the cross-correlation is not sufficiently greater than the next highest peak or not sufficiently greater than the average.

12. The portable device of claim 9, wherein the portable device is configured to improve the accuracy of the calibration by delaying a preamble signal used in the cross-correlation calculation.

13. The portable device of claim 9, wherein the portable device is configured to improve the accuracy of the calibration by filtering the signal received by the synchronization circuit according to those frequencies detectable by the synchronization circuit using the at least one microphone.

14. The portable device of claim 1, further comprising: at least one user interaction control connected to the signal processor and configured to be adjustable.

15. The portable device of claim 1, further comprising a battery, and an internal power management circuit associated with the battery.

16. A method of synchronizing sounds using a portable device, the method comprising:

providing the portable device, the portable device comprising: a wireless receiver; a signal processor; a wireless source; at least one microphone configured to receive audio from outside the portable device; and at least one of at least one speaker and a line output;

receiving a wireless signal using the wireless receiver;

processing the signal using the signal processor;

transmitting a wireless signal using the wireless source in accordance with audio received from the at least one microphone; and

emitting sound using the at least one speaker in accordance with audio received from the at least one microphone and/or transmitting signals to the line output in accordance with audio received from the at least one microphone.