Audio system
AssigneeAlps Alpine Co., Ltd.
InventorsNozomu Saito, Keita Tanno
Life of this patent
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Abstract
A voice output from an i-th audio source apparatus is adjusted with a frequency transfer function Wii(f) set in an i-th noise reduction filter and is output from an i-th speaker. In the noise reduction filter, a frequency transfer function Wii(f) is set in which the sound is made smaller at frequencies where the gain of the frequency transfer function Cim(f) from the SPKi to a user tends to be relatively larger than the gain of the frequency transfer function Cii(f) from the SPKi to the user, and the sound is increased at frequencies where the gain of Cim(f) tends to be relatively smaller than the gain of Cii(f), where m is an integer excluding i from 1 to n.
Claims4
An audio system configured to output sound of different sound sources for each of n users from a 1st user to an n-th user, where is n>2, the audio system comprising:
- n sound source devices from the 1st to the n-th;
- n speakers from the 1st to the n-th;
- and
- n filters,
- wherein the i-th filter, where i is an integer of 1 to n, is configured to transmit a sound output from the i-th sound source device to the i-th speaker with a set frequency transfer characteristic;
- wherein the frequency transfer characteristic set for the i-th filter is a frequency transfer function for reducing sound at a frequency at which a gain of a frequency transfer function from the i-th speaker to the m-th user is greater than a gain of a frequency transfer function from the i-th speaker to the i-th user, and increasing sound at a frequency at which of a gain of a frequency transfer function from the i-th speaker to the m-th user is less than a gain of a frequency transfer function from the i-th speaker to the i-th user, where m is an integer excluding i from 1 to n;
- and
- wherein when Cii(f) is a frequency transfer function from the i-th speaker to the i-th user, C*ii(f) is a complex conjugate of Cii(f), Cim(f) is a frequency transfer function from the i-th speaker to the m-th user, and C*im(f) is a complex conjugate of Cim(f), a frequency transfer characteristic Wij set for the i-th filter is expressed by the equation:
- W
- ii
- (
- f
- )
- =
- 1
- 1
- +
- ∑
- m
- =
- 1
- m
- ≠
- i
- n
- (
- C
- im
- *
- (
- f
- )
-
- C
- im
- (
- f
- )
- /
- C
- ii
- *
- (
- f
- )
-
- C
- ii
- (
- f
- )
- )
- .
Dependencies are inferred from the claim text.