Intelligent speaker training using microphone feedback and pre-loaded templates

• US 6,766,025 B1
• Filed: 03/15/1999
• Issued: 07/20/2004
• Est. Priority Date: 03/15/1999
• Status: Expired due to Term

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Sessions, D. C., Levy, Paul S.
• Primary Examiner(s): Harvey, Minsun Oh
• Application Number:
  US09/267,618
• Time in Patent Office: 1,954 Days
• Field of Search: 381/96, 381/55, 381/56, 381/57, 381/58, 381/59, 381/95
• US Class Current: 381/96
• CPC Class Codes: H04R 27/00 Public address systems circuits for preventing acoustic reaction H04R3/02; circuits for distributing signals to loudspeakers H04R3/12; monitoring or testing arrangements for public address systems H04R29/007; amplifiers H03F
• CPC Class Codes: H04R 29/001 for loudspeakers H04R29/007 takes precedence
• CPC Class Codes: H04R 3/04 for correcting frequency response
• CPC Class Codes: H04S 7/301 Automatic calibration of stereophonic sound system, e.g. with test microphone

Abstract

A programmable speaker uses characterization data stored within the memory of the speaker and digital signal processing (DSP) to digitally perform transform functions on input audio signals to compensate for speaker related distortion and listening environment distortion. In a manufacturing environment, a non-intrusive system and method for tuning the speaker is performed by applying a reference signal and a control signal to the input of the programmable speaker. A microphone detects an audible signal corresponding to the input reference signal at the output of the speaker and feeds it back to a tester which analyzes the frequency response of the speaker by comparing the input reference signal to the audible output signal from the speaker. Depending on the results of the comparison, the tester provides to the speaker an updated digital control signal with new characterization data which is then stored in the speaker memory and used to again perform transform functions on the input reference signal. The tuning feedback cycle continues until the input reference signal and the audible output signal from the speaker exhibit the desired frequency response as determined by the tester. In a consumer environment, a microphone is positioned within selected listening environments and the tuning device is again used to update the characterization data to compensate for distortion affects detected by the microphone within the selected listening environment.

Claims

1. A programmable speaker, comprising:

a programmable portion including a processing portion and a memory storage area for storing characterization data, said processing portion for performing a transform function on an input audio signal using said characterization data, said programmable portion receiving and processing said audio input signal and outputting a transformed signal wherein said transform function corresponds to the inverse transform function of the product of a first transform function corresponding to speaker related distortion and a second transform function corresponding to listening environment distortion; and

an output portion for converting said transformed signal into an audible analog signal.

2. The speaker as described in claim 1 wherein said characterization data comprises sets of characterization data each corresponding to a different selected listening environment wherein one set is used when performing said transform function dependent on said selected listening environment.

3. The speaker as described in claim 1 wherein said programmable portion includes a means for receiving said characterization data from an external source and storing said received characterization data in said memory storage area.

4. The speaker as described in claim 1 wherein said processing portion comprises a digital signal processing unit, its corresponding memory system, and function specific hardware for performing said transform function on said input signal using said characterization data to generate said transformed signal.

5. The speaker as described in claim 1 wherein said memory storage area is a non-volatile memory.

6. The speaker as described in claim 1 wherein more than one transform function is performed on said input signal by said processing portion each transform function using different characteristic data.

7. The speaker as described in claim 1 wherein said characterization data is weighting coefficient values of said transform function.

8. A speaker system, comprising:

a speaker disposed in a speaker enclosure;

a processing portion, coupled to the speaker, and disposed in the speaker enclosure;

a first stored set of weighting coefficients, coupled to the processing portion, for providing control information to the processing portion to compensate for speaker related distortion;

a microphone disposed in a listening environment; and

a tuning means coupled to the microphone, and further coupled to the processing portion, the tuning means adapted to provide, based at least in part upon the first stored set of weighting coefficients and a signal received from the microphone, a second stored set of weighting coefficients, the second stored set of weighting coefficients for providing control information to the processing portion to compensate for both speaker related distortion and listening environment distortion.

9. The speaker system of claim 8, wherein the first set of weighting coefficients is based, at least in part, upon a comparison of a reference input signal, to an audio output signal produced by the speaker system in response to receiving the reference input signal.