Audio Signal Processing

• US 20060291669A1
• Filed: 08/10/2006
• Published: 12/28/2006
• Est. Priority Date: 06/21/2001
• Status: Active Grant

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Aylward, J. Richard, Anderson, Erik E.
• Granted Patent: US 8,175,292 B2
• Time in Patent Office: Days
• US Class Current: 381/98
• CPC Class Codes: H04S 3/00 Systems employing more than two channels, e.g. quadraphonic H04S5/00, H04S7/00 take precedence

Abstract

A method for processing and transducing audio signals. An audio system has a first audio signal and a second audio signal that have amplitudes. A method for processing the audio signals includes dividing the first audio signal into a first spectral band signal and a second spectral band signal; scaling the first spectral band signal by a first scaling factor proportional to the amplitude of the second audio signal; and scaling the first spectral band signal by a second scaling factor to create a second signal portion. Other portions of the disclosure include application of the signal processing method to multichannel audio systems, and to audio systems having different combinations of directional loudspeakers, full range loudspeakers, and limited range loudspeakers.

Claims

1-27. -27. (canceled)

28. In an audio system having a first audio signal, a second audio signal and a directional loudspeaker unit, a method for processing said audio signals comprising,

electroacoustically directionally transducing said first audio signal to produce a first signal radiation pattern;

electroacoustically directionally transducing said second audio signal to produce a second signal radiation pattern;

wherein said first signal radiation pattern and said second signal radiation pattern are alternatively and user selectively similar or different.

29. A method for processing audio signals in accordance with claim 28 with an audio system including a source of a third audio signal and a speaker unit separate from said directional loudspeaker unit further comprising,

electroacoustically transducing said third audio signal by said speaker unit.

30. A method for processing audio signals in accordance with claim 29,

wherein said third audio signal is substantially limited to a frequency range having a lower limit at a frequency that has a corresponding wavelength that approximates the dimensions of a human head and

wherein said speaker unit is constructed and arranged to electroacoustically transduce audio signals having frequencies in said frequency range.

31. A method for processing audio signals in accordance with claim 30, wherein said third audio signal comprises a first spectral band of a scaled, filtered audio signal representing a directional channel of a multichannel audio system.

32. A method for processing audio signals in accordance with claim 29, wherein said third audio signal comprises a filtered scaled first spectral band of an input audio signal representing a directional channel of a multichannel audio system and a second spectral band of said input audio signal.

33. In an audio system having a first audio signal, a second audio signal, a third audio signal that is substantially limited to a frequency range having a lower limit at a frequency that has a corresponding wavelength that approximates the dimensions of a human head, a directional loudspeaker unit, and a loudspeaker unit, distinct from said directional loudspeaker unit, a method for processing said audio signals comprising,

electroacoustically directionally transducing by said directional loudspeaker unit said first audio signal to produced a first radiation pattern;

electroacoustically directionally transducing by said directional loudspeaker unit said second audio signal to produce a second radiation pattern; and

electroacoustically transducing by said distinct loudspeaker unit said third audio signal.

34. A method for processing audio signals in accordance with claim 33, wherein said electroacoustically directionally transducing comprises electroacoustically directionally transducing said first audio signal so that said first radiation pattern has a primary axis in a first direction and so that said second radiation pattern has a primary axis in a second direction different from said first direction.

35. A method for processing audio signals in accordance with claim 33, wherein said third audio signal comprises a first spectral band of a scaled, filtered audio signal representing a directional channel of a multichannel audio system.

36-41. -41. (canceled)

42. A method for processing an audio signal, comprising,

filtering said audio signal by a first filter, said first filter having a frequency response and time delay effect similar to the human head to produce a once-filtered audio signal;

filtering said once-filtered audio signal by a second filter, said second filter having a frequency response and time delay effect inverse to the frequency and time delay effect of a human head on a sound wave.

43. A method for processing audio signals in accordance with claim 42, wherein said second filter has a time delay effect inverse to the frequency and time delay effect of a human head on a sound wave that originates at a preselected orientation relative to said human head.

44. A method for processing audio signals in accordance with claim 43, wherein said preselected orientation is an angle approximately thirty degrees relative to said human head.

45. A method for processing audio signals in accordance with claim 43, wherein said preselected orientation is a measured angle.

46-54. -54. (canceled)