Room acoustics correction device

• US 20070121955A1
• Filed: 11/30/2005
• Published: 05/31/2007
• Est. Priority Date: 11/30/2005
• Status: Abandoned Application

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Johnston, James, Smirnov, Sergey
• Application Number:
  US11/289,328
• Publication Number:
  US 20070121955A1
• Time in Patent Office: Days
• US Class Current: 381/56
• CPC Class Codes: H04S 7/301 Automatic calibration of stereophonic sound system, e.g. with test microphone

Abstract

A method and system are provided for improving the preferred listening environment of a sound system. Initially, a calibration pulse is generated from one or more rendering devices. Next, the calibration pulse is captured at a microphone attached to the rendering devices. Thereafter, one or more time delay, gain, and frequency response characteristics of the sound system are calculated using the captured calibration pulse. Based on these calculations, the time delay, gain, and frequency response characteristics of the rendering devices are adjusted respectively to cause the sound generated from the rendering devices to reach a listener'"'"'s acoustic preference.

Claims

1. A method for improving the listening environment of a sound system comprising:

generating a calibration pulse from one or more rendering devices, the calibration pulse having an autoconvolution peak and a bandwidth complimentary to the noise floor in the space;

capturing the calibration pulse at a microphone attached to a calibration computing device;

calculating at least one of;

a time delay, gain, and frequency response characteristic corresponding to the sound system using the captured calibration pulse; and

adjusting at least one of;

the time delays, gain, and frequency response characteristic of the rendering devices to cause the sound generated from the rendering devices to reach a listener'"'"'s acoustic preference.

2. The method of claim 1, further comprising:

adjusting the delays for the rendering devices such that the audio content generated by each rendering device reaches a preferred listening position simultaneously.

3. The method of claim 1, further comprising:

creating an inverse filter using the time delays, gain, and frequency response characteristics for correcting one or more frequency errors of the sound system.

4. The method of claim 3, wherein creating an inverse filter further comprises calculating a first LPC filter by flattening a frequency spectrum at low frequencies.

5. The method of claim 4, wherein creating an inverse filter further comprises calculating a second LPC filter by flattening a frequency spectrum at high frequencies.

6. The method of claim 5, wherein creating an inverse filter further comprises convolving the first LPC filter with the second LPC filter to generate an inverse filter.

7. The method of claim 1, further comprising:

equalizing the acoustic performance of the rendering devices by adjusting the gain for the rendering devices.

8. The method of claim 1, further comprising:

measuring the gain directly from the rendering devices using the calibration pulse.

9. The method of claim 1, further comprising obtaining a bandwidth for the calibration pulse by using a mid band probe signal.

10. A method for calibrating a sound system comprising:

generating a test signal from one or more rendering devices;

capturing the test signal at a microphone attached to a calibration computing device, the captured test signal having a first arrival portion;

transmitting the captured test signal to the calibration computing device;

calculating an inverse filter using the first arrival portion of the test signal at the calibration computing device;

generating a room correction profile at the calibration computing device; and

adjusting the time delay, gain, and frequency response characteristics of the rendering devices using the room correction profile.

11. The method of claim 10, wherein calculating an inverse filter further comprises:

calculating a first LPC filter by flattening a frequency spectrum at low frequencies.

12. The method of claim 11, wherein calculating an inverse filter further comprises:

calculating a second LPC filter by flattening a frequency spectrum at high frequencies.

13. The method of claim 12, wherein calculating an inverse filter further comprises:

convolving the first LPC filter with the second LPC filter to generate an inverse filter.

14. The method of claim 10, wherein generating a room correction profile further comprises:

calculating the analytic energy envelope using the calculated energy corresponding to the inverse filter.

15. The method of claim 10, further comprising:

measuring the gain directly from the rendering devices using the test signal.

16. The method of claim 10, further comprising obtaining a bandwidth for the test signal by using a mid band probe signal.

17. The method of claim 14, wherein calculating the gain is based on the analytic energy envelope.