# US 10,319,389 B2 · Automatic timbre control

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- Number: US 10,319,389 B2
- Document ID: US10319389B2
- Status: Granted
- Kind: B2
- Application number: 14/906,687
- Filed: 2014-07-02
- Published: 2016-06-09
- Granted: 2019-06-11
- Earliest claimed: 2013-07-22
- Assignees: Harman Becker Automotive Systems GmbH
- Applicants: Harman Becker Automotive Systems GmbH
- Inventors: Markus Christoph
- Web page: https://patentgrep.com/patent/US10319389B2

## CPC

- G10L 21/0364: for improving intelligibility
- G10L 19/0212: {using orthogonal transformation}
- G10L 21/0232: Processing in the frequency domain
- G10L 21/034: Automatic adjustment
- H04S 7/30: {Control circuits for electronic adaptation of the sound field}
- G10L 2021/02163: {Only one microphone}
- H04R 3/04: for correcting frequency response
- G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
- H04S: STEREOPHONIC SYSTEMS
- H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K)

## Abstract

A system and method for automatically controlling the timbre of a sound signal in a listening room are also disclosed, which include the following: producing sound in the time domain from a re-transformed electrical sound signal in the time domain, in which an electrical sound signal in the time domain being transformed into electrical sound signal in the frequency domain and the electrical sound signal in the frequency domain being re-transformed into the re-transformed electrical sound signal; generating a total sound signal representative of the total sound in the room, processing the total sound signal to extract an estimated ambient noise signal representing the ambient noise in the room; and adjusting the spectral gain of the electrical sound signal in the frequency domain dependent on the estimated ambient noise signal, the electrical sound signal and a room dependent gain signal.

## Claims

### Claim 1

A method for automatically controlling a timbre of a sound signal in a listening room, comprising:
producing sound in a time domain from a re-transformed electrical sound signal in the time domain, in which a first electrical sound signal in the time domain is transformed into a second electrical sound signal, in a frequency domain and the second electrical sound signal in the frequency domain is re-transformed into the re-transformed electrical sound signal;
generating a total sound signal representative of a total sound in a listening room, wherein the total sound comprises a sound output from a loudspeaker and ambient noise in the listening room;
processing the total sound signal to extract an estimated ambient noise signal representing the ambient noise in the listening room; and
adjusting a spectral gain of the second electrical sound signal in the frequency domain dependent on the estimated ambient noise signal, the first electrical sound signal and a room dependent gain signal;
wherein the room dependent gain signal is determined from reference room data and estimated room data,
wherein a mean calculation and a voice activity detection is performed to provide the estimated ambient noise signal,
wherein the voice activity detection is performed via a voice activity detector,
wherein the spectral gain of the second electrical sound signal is adjusted, according to psychoacoustic parameters, and
wherein the spectral gain corresponds to a gain that is frequency dependent.

### Claim 2 (depends on 1)

The method of claim 1, wherein the psychoacoustic parameters comprise psychoacoustic frequency scaling.

### Claim 3 (depends on 1)

The method of claim 1, wherein a mean calculation and a noise estimation is performed to provide the estimated ambient noise signal.

### Claim 4 (depends on 3)

The method of claim 3, wherein the noise estimation employs nonlinear smoothing.

### Claim 5 (depends on 1)

The method of claim 1, further comprising receiving a fader/balance setting, wherein adjusting the spectral gain of the second electrical sound signal is dependent on the fader/balance setting.