Apparatus for stereophonic sound positioning

• US 8,213,646 B2
• Filed: 06/18/2009
• Issued: 07/03/2012
• Est. Priority Date: 06/20/2008
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Iguchi, Sei, Kobayashi, Wataru, Furuya, Kazuhiko, Yonai, Keita, Matsumoto, Yuji
• Primary Examiner(s): Goins, Davetta W
• Assistant Examiner(s): Ganmavo, Kuassi
• Application Number:
  US12/457,670
• Publication Number:
  US 20090316939A1
• Time in Patent Office: 1,111 Days
• Field of Search: 381/86, 381/310, 381/300, 381/302, 340/435, 340/436, 340/437, 340/551, 340/552, 340/565
• US Class Current: 381/302
• CPC Class Codes: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04R 5/04 Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments combinations of amplifiers H03F3/68; stereophonic systems H04S
• CPC Class Codes: H04S 2420/01 Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF's] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD]
• CPC Class Codes: H04S 7/30 Control circuits for electronic adaptation of the sound field

Abstract

A stereophonic apparatus uses three speakers respectively installed toward a front of a vehicle on both shoulders of a seat back of a driver'"'"'s seat and toward a back of the vehicle on an exact center in front of a driver. This configuration provides more effectively exerted positioning effects for a virtual sound source realized by using the three speakers, especially for the effects in a frontward field of sound.

Claims

1. A vehicular stereophonic sound apparatus for presenting an object condition of an object based on sensor information that is representative of an in-and-about condition of a vehicle and for outputting notification sound from a virtual sound source toward an occupant of the vehicle, the apparatus comprising:

a right and a left main-speakers installed respectively equidistantly on a right side and a left side relative to a right ear and a left ear of the occupant;

a sub-speaker installed on a right-front position of the occupant, such that the sub-speaker is disposed in front of the occupant on a center plane of the occupant;

a control unit for outputting a control signal for generating virtual sound based on determination of the object condition to be presented for the occupant according to the sensor information;

a positioning unit for positioning a sound image of the object in an actual direction by performing, for a right and a left audio signals respectively directed to the right and the left main-speakers, signal processing that utilizes Head-Related Transfer Function that reflects a position of the object based on the control signal from the control unit;

an enhance unit for enhancing the sound image by performing, for the right and the left audio signals respectively directed to the right and the left main-speakers, signal processing according to the position of the object;

a delay unit for correcting a difference of sound arrival times to the right and the left ears due to a difference of speaker-to-ear distances between the right and left main-speakers and the sub-speakers relative to the right and the left ears based on the control signal from the control unit according to the actual direction of the object;

a filter unit for processing the audio signal directed to the sub-speaker based on the control signal from the control unit according to the actual direction of the object, the filter unit being configured as an FIR filter with a tap number of N; and

a volume adjustment unit for adjusting sound volume of the right and the left main-speakers and the sub-speaker independently based on the control signal from the control unit according to the actual direction and a distance of the object, wherein

the tap number of N of the FIR filter is determined based on the actual direction of the object,

N is set to a lower setting when the actual direction of the object is from a side of the vehicle to a front of the vehicle, than when the actual direction of the object is from a rear of the vehicle.

2. A vehicular stereophonic sound apparatus for presenting an object condition of an object based on sensor information that is representative of an in-and-about condition of a vehicle and for outputting notification sound from a virtual sound source toward an occupant of the vehicle, the apparatus comprising:

a right and a left main-speakers installed respectively equidistantly on a right side and a left side relative to a right ear and a left ear of the occupant;

a sub-speaker installed on a right-front position of the occupant, such that the sub-speaker is disposed in front of the occupant on a center plane of the occupant;

a control unit for outputting a control signal for generating virtual sound based on determination of the object condition to be presented for the occupant according to the sensor information;

a positioning unit for positioning a sound image of the object in an actual direction by performing, for a right and a left audio signals respectively directed to the right and the left main-speakers, signal processing that utilizes Head-Related Transfer Function that reflects a position of the object based on the control signal from the control unit;

an enhance unit for enhancing the sound image by performing, for the right and the left audio signals respectively directed to the right and the left main-speakers, signal processing according to the position of the object;

a delay unit for correcting a difference of sound arrival times to the right and the left ears due to a difference of speaker-to-ear distances between the right and left main-speakers and the sub-speakers relative to the right and the left ears based on the control signal from the control unit according to the actual direction of the object;

a filter unit for processing the audio signal directed to the sub-speaker based on the control signal from the control unit according to the actual direction of the object, the filter unit being configured as an FIR filter with a tap number of N; and

a volume adjustment unit for adjusting sound volume of the right and the left main-speakers and the sub-speaker independently based on the control signal from the control unit according to the actual direction and a distance of the object,

wherein

the tap number of N of the FIR filter is determined based on the actual direction of the object,

N is set to a lower setting when the actual direction of the object is from a side of the vehicle to a front of the vehicle, than when the actual direction of the object is from a rear of the vehicle, and

the object that is represented by the sound image is actually positioned outside the vehicle.

3. The vehicular stereophonic sound apparatus of claim 2 further comprising:

a sound contents storage unit for storing sound contents that are to be presented for the occupant of the vehicle; and

a sound contents selection unit for selecting the sound contents according to the control signal from the control unit.

4. The vehicular stereophonic sound apparatus of claim 3, wherein

the sound contents selection unit selects the sound contents so as to simulate a kind of the object to be presented.