Vehicle sound system

• US 5,204,971 A
• Filed: 09/26/1991
• Issued: 04/20/1993
• Est. Priority Date: 10/05/1990
• Status: Expired due to Term

• Current Assignee: Alpine Electronics Incorporated (Alps Alpine Co., Ltd.)
• Original Assignee: Alpine Electronics Incorporated (Alps Alpine Co., Ltd.)
• Inventors: Takahashi, Masahiro, Watanabe, Yoshikatsu
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Woldu, Almaz
• Application Number:
  US07/766,615
• Time in Patent Office: 572 Days
• Field of Search: 455/238.1, 455/345, 455/186.1, 455/186.2, 455/185.1, 455/200.1, 381/86
• US Class Current: 455/185.1
• CPC Class Codes: H03G 3/32 the control being dependent upon ambient noise level or sound level
• CPC Class Codes: H04B 1/20 for coupling gramophone pick-up, recorder output, or microphone to receiver

Abstract

A sound system for a vehicle detects the amount of noise, such as road noise, and automatically controls the audio volume in accordance with the noise amount. There are provided a plurality of tables, in which the relationships among the present volume, the noise amount and the volume increase amount of the audio signal are stored. Once one of the plurality of tables is selected by using a table selection key according to the type of the vehicle or the sound system, the volume is automatically controlled based on the characteristic of the selected table.

Claims

1. A vehicle sound system comprising:

detection means for detecting noise;

level conversion means for converting the noise detected by said detection means into a direct-current level signal;

audio signal reproduction means for reproducing an audio signal;

volume control means for increasing or decreasing the audio signal reproduced by said audio signal reproduction means by a volume change amount according to a volume control signal;

a plurality of tables in each of which a relationship among an output value of the audio signal, the direct-current signal and the volume change amount of the audio signal is stored;

selection means for selecting a desired table from said plurality of tables; and

control means for producing said volume control signal for controlling said volume control means according to said direct-current signal and said output value of the audio signal.

2. A vehicle sound system according to claim 1, wherein said control means controls said volume control means when noise components are continuously input for a predetermined time.

3. A vehicle sound system according to claim 1, wherein said control means performs fade-in and fade-out according to a volume change curve having a predetermined time constant in controlling said volume control means.

4. A vehicle sound system according to claim 1, wherein said plurality of tables are prepared in accordance with types of vehicles or sound systems.

5. A vehicle sound system according to claim 1, wherein said plurality of tables each are a control parameter table stored in an EEPROM.