# US 12,008,998 B2 · Audio system height channel up-mixing

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- Number: US 12,008,998 B2
- Document ID: US12008998B2
- Status: Granted
- Kind: B2
- Application number: 17/850,293
- Filed: 2022-06-27
- Published: 2022-10-13
- Granted: 2024-06-11
- Earliest claimed: 2020-11-03
- Assignees: Bose Corporation
- Applicants: Bose Corporation
- Inventors: James Tracey
- Web page: https://patentgrep.com/patent/US12008998B2

## CPC

- G10L 19/008: Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
- H04S 5/00: Pseudo-stereo systems, e.g. in which additional channel signals are derived from monophonic signals by means of phase shifting, time delay or reverberation
- H04S 1/007: {in which the audio signals are in digital form (data reduction aspects thereof based on psychoacoustics G10L19/02)}
- H04S 5/005: {of the pseudo five- or more-channel type, e.g. virtual surround}
- H04S 3/008: {in which the audio signals are in digital form, i.e. employing more than two discrete digital channels (data reduction aspects thereof based on psychoacoustics G10L19/02)}
- H04S 2400/01: Multi-channel, i.e. more than two input channels, sound reproduction with two speakers wherein the multi-channel information is substantially preserved
- G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
- H04S: STEREOPHONIC SYSTEMS

## Abstract

Audio system height channel up-mixing that is configured to develop two or more height channels from audio sources that do not include height-related encoding. The up-mixing involves determining correlations and normalized channel energies between input audio signals. At least two height channels (e.g., left and right height audio signals) are developed from the correlations and normalized energies.

## Claims

### Claim 1

A computer-implemented method for an audio system with at least two audio drivers, the method comprising:
determining correlations between input audio signals that do not include height components;
determining normalized energies of the input audio signals; and
developing at least left and right height audio signals from the determined correlations and normalized channel energies, wherein the at least left and right height audio signals are configured for playback using one or more of the at least two audio drivers.

### Claim 2 (depends on 1)

The method of claim 1, further comprising performing a Fourier transform on the input audio signals prior to the determining of the correlations and prior to the determining of the normalized energies, thereby resulting in a series of bins to be used for at least one of the determining of the correlations and the determining of the normalized energies.

### Claim 3 (depends on 2)

The method of claim 2, wherein the determined correlations are based on the series of bins from the Fourier transform.

### Claim 4 (depends on 2)

The method of claim 2, wherein the determined normalized energies are based on the series of bins from the Fourier transform.

### Claim 5 (depends on 2)

The method of claim 2, further comprising partitioning the series of bins using sub-octave spacing.

### Claim 6 (depends on 1)

The method of claim 1, further comprising developing left front height, right front height, left back height, and right back height audio signals.

### Claim 7 (depends on 1)

The method of claim 1, further comprising developing de-correlated left and right audio signals.

### Claim 8 (depends on 7)

The method of claim 7, further comprising performing cross-talk cancellation on the de-correlated left and right audio signals.

### Claim 9 (depends on 1)

The method of claim 1, wherein a user can enable and disable playback of the at least left and right height audio signals.

### Claim 10 (depends on 1)

The method of claim 1, wherein a user can customize a volume of the at least left and right height audio signals that is relative to a volume of one or more other audio signals of the audio system.

### Claim 11

An audio system comprising:
at least two drivers; and
at least one processor configured to
determine correlations between input audio signals that do not include height components,
determine normalized energies of the input audio signals, and
develop at least left and right height audio signals from the determined correlations and normalized energies, wherein the at least left and right height audio signals are configured for playback using one or more of the at least two audio drivers.

### Claim 12 (depends on 1)

The audio system of claim 1, wherein the at least one processor is further configured to perform a Fourier transform on the input audio signals prior to the determining of the correlations and prior to the determining of the normalized energies, thereby resulting in a series of bins to be used for at least one of the determining of the correlations and the determining of the normalized energies.

### Claim 13 (depends on 12)

The audio system of claim 12, wherein the determined correlations are based on the series of bins from the Fourier transform.

### Claim 14 (depends on 12)

The audio system of claim 12, wherein the determined normalized energies are based on the series of bins from the Fourier transform.

### Claim 15 (depends on 12)

The audio system of claim 12, wherein at least one processor is further configured to partition the series of bins using sub-octave spacing.

### Claim 16 (depends on 11)

The audio system of claim 11, wherein the at least one processor is further configured to develop left front height, right front height, left back height, and right back height audio signals.

### Claim 17 (depends on 11)

The audio system of claim 11, wherein the at least one processor is further configured to develop de-correlated left and right audio signals.

### Claim 18 (depends on 17)

The audio system of claim 17, wherein the at least one processor is further configured to perform cross-talk cancellation on the de-correlated left and right audio signals.

### Claim 19 (depends on 11)

The audio system of claim 11, wherein a user can enable and disable playback of the at least left and right height audio signals.

### Claim 20 (depends on 11)

The audio system of claim 11, wherein a user can customize a volume of the at least left and right height audio signals that is relative to a volume of one or more other audio signals of the audio system.