06760451 is referenced by 86 patents and cites 2 patents.

A prefilter (

5

) for an audio system comprising a loudspeaker (

1

) in a room (

2

), which corrects both amplitude and phase errors due to the loudspeaker (

1

) by a linear phase correction filter response and corrects the amplitude response of the room (

2

) whilst introducing the minimum possible amount of extra phase distortion by employing a minimum phase correction filter stage. A test signal generator (

8

) generates a signal comprising a periodic frequency sweep with a greater phase repetition period than the frequency repetition period. A microphone (

7

) positioned at various points in the room (

2

) measures the audio signal processed by the room (

2

) and loudspeaker (

1

), and a coefficient calculator (

6

) (e.g. a digital signal processor device) derives the signal response of the room and thereby a requisite minimum phase correction to be cascaded with the linear phase correction already calculated for the loudspeaker (

1

). Filter (

5

) may comprise the same digital signal processor as the coefficient calculator (

6

). Applications in high fidelity audio reproduction, and in car stereo reproduction.

Title
Compensating filters
Application Number
9/83276
Publication Number
6760451 (B1)
Application Date
May 22, 1998
Publication Date
July 6, 2004
Inventor
Michael Anthony Gerzon
57 Juxon Street, Jericho, Oxford
US
Peter Graham Craven
11 Wessex Way, Grove, Wantage, Oxon
US
Agent
Nixon & Vanderhye P C
US
IPC
H03G 5/00
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