Audio signal processing

• US 8,099,293 B2
• Filed: 08/13/2008
• Issued: 01/17/2012
• Est. Priority Date: 06/08/2004
• Status: Active Grant

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Kulkarni, Abhijit
• Primary Examiner(s): Vo, Huyen X.
• Application Number:
  US12/190,653
• Publication Number:
  US 20080304671A1
• Time in Patent Office: 1,252 Days
• Field of Search: 704500-504, 704/229, 704/220, 704/200.1, 704/200, 704/221
• US Class Current: 704/501
• CPC Class Codes: 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
• CPC Class Codes: H04S 5/005 of the pseudo five- or more-channel type, e.g. virtual surround

Abstract

An audio system for processing two channels of audio input to provide more than two output channels. The input may be conventional stereo material or compressed audio signal data. The audio processing includes separating the input signals into frequency bands and processing the frequency bands according to processes which may differ from band to band. The audio processing includes no processing of L−R signals.

Claims

1. A method for processing audio signals, the method comprising:

separating audio signal data that were previously compressed by an unknown compression technique in two input audio channels into frequency bands;

separately processing the frequency bands; and

combining the separately processed frequency bands to provide n output audio channels, where n>

2.

2. A method for processing audio signals in accordance with claim 1, wherein the separately processing the frequency bands includes scaling a first channel first frequency band signal, scaling a second channel first frequency band signal, and wherein the separately processing does not include processing a signal representing the difference between any portions of the audio signals in the two input audio channels.

3. Apparatus for processing audio signals in at least two input audio channels to provide more than two output audio channels, the apparatus comprising:

circuitry for separating audio signal data that were previously compressed by an unknown compression technique in the input audio channel signals into frequency bands;

circuitry for separately processing the frequency bands; and

circuitry for combining the separately processed frequency bands to provide the more than two output audio channels.