Bandwidth Improvement And Distortion Reduction In Closed-box Loudspeaker Systems
- Technology Application
- Home entertainment systems High-end car audio systems
- Detailed Technology Description
- None
- Supplementary Information
- Patent Number: US6584204B1
Application Number: US1998209645A
Inventor: Al Ali, Khalid M. | Packard, Andrew | Tongue, Benson H.
Priority Date: 11 Dec 1997
Priority Number: US6584204B1
Application Date: 10 Dec 1998
Publication Date: 24 Jun 2003
IPC Current: H03G000332 | H03G000522 | H04R000300
US Class: 381096 | 3810943
Assignee Applicant: The Regents of the University of California
Title: Loudspeaker system with feedback control for improved bandwidth and distortion reduction
Usefulness: Loudspeaker system with feedback control for improved bandwidth and distortion reduction
Summary: For e.g. playback system, high fidelity car audio system and home theater system used in e.g. movie theater, recording studios and concerts.
Novelty: Loudspeaker system used in e.g. recording studios, has filter unit for generating controlled signal to reduce distortion of audible signal in predefined sub-bass frequency range
- Industry
- Electronics
- Sub Category
- 3C/Gadgets
- Application No.
- 6584204
- Others
-
Related Materials
Loudspeakers: Modeling and Control; Khalid Mohammad Al-Ali; Ph.D Thesis
Tech ID/UC Case
18432/1996-057-0
Related Cases
1996-057-0
- *Abstract
-
Using novel feedback sensing techniques and a control algorithm (together referred to as "the control system"), researchers at the University of California, Berkeley, have expanded the bandwidth of a professional grade low-frequency transducer, while simultaneously reducing the distortion. The unique idea is that the control system is physically independent of the loudspeaker, allowing the introduction of this technology both as next generation and in combination with existing subwoofers.
For an 18-inch professional grade subwoofer, the control system produced a significant improvement in the sub-bass Sound Pressure Level (SPL) response, and reduced harmonic distortion over the controlled region for output levels reaching 140 dB SPL (re 20 ?Pa, 1.25" from the speaker). This was especially evident at lower frequencies where the Total Harmonic Distortion (THD) was reduced by a factor of 0.55 (from 7.0% for the stock system to 3.9% for the closed-loop system). Listening tests consisting of played-back music and test tones using the A/B double blindfold methodology further verified the significant performance enhancements.
- *IP Issue Date
- Jun 24, 2003
- *Principal Investigator
-
Name: Khalid Al-Ali
Department:
Name: Andrew Packard
Department:
Name: BENSON TONGUE
Department:
- Country/Region
- USA
