JP4345349B2

JP4345349B2 - In-vehicle sound reproduction device

Info

Publication number: JP4345349B2
Application number: JP2003134086A
Authority: JP
Inventors: 昭典長谷川; 文靖今野
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2003-05-13
Filing date: 2003-05-13
Publication date: 2009-10-14
Anticipated expiration: 2023-05-13
Also published as: JP2004338430A

Description

【０００１】
【発明の属する技術分野】
本発明は自動車の走行状態による車室内の音響特性の変化を自動的に補正して良好なスピーカ再生音を得るための車載用再生装置に関するものである。
【０００２】
【従来の技術】
周囲の騒音レベルの変動に応じてスピーカから再生される出力レベルを補正する従来の車載用音響再生装置のブロック図を図７に示す。同図において入力端子１から入力された信号は、入力信号の増幅率を変える可変利得増幅器２を通り電力増幅器３で電力増幅され、スピーカボックス６内のスピーカ４で再生される。
【０００３】
そして、スピーカボックス６の周辺に配置された第１のマイクロホン７の信号とスピーカボックス６の内部に配置された第２のマイクロホン８の信号は、それぞれ最低共振周波数（ｆ₀）が同一な第１の低域通過フィルタ９と第１の高域通過フィルタ１０を通り演算増幅器１１に入力される。第１の低域通過フィルタ９と第１の高域通過フィルタ１０の最低共振周波数（ｆ₀）をスピーカ４の最低共振周波数（ｆ₀）に合わせることにより、第１の低域通過フィルタ９と第１の高域通過フィルタ１０の出力特性は周波数に対してほぼ同じ帯域通過特性でかつ位相が逆位相となる。第１の低域通過フィルタ９と第１の高域通過フィルタ１０の出力信号を演算増幅器１１にて演算し、第１の低域通過フィルタ９の出力信号からスピーカ４の再生音を減少させることにより受聴点でのスピーカ４の再生音と騒音の混合音を模擬する。そして第１の増幅器１２により可変利得増幅器２の出力信号と同じ大きさになるように調整される。
【０００４】
一方、可変利得増幅器２の出力信号は第２の低域通過フィルタ１５と第２の高域通過フィルタ１６により、騒音がない場合の演算増幅器１１の出力特性と同じ帯域通過特性に調整される。
【０００５】
上記２つの信号はそれぞれ第１の絶対値回路１３および第２の絶対値回路１７で正、負それぞれの絶対値に変換され、第１の積分器１４、第２の積分器１８で積分される。積分された正、負の絶対値信号は加算器１９で加算されることにより２つの信号の差が比較演算され、第２の増幅器２０から可変利得増幅器２の増幅率を変化させる信号が可変利得増幅器２に出力される。そして、スピーカボックス６の周辺に配置された第１のマイクロホン７とスピーカボックス６の内部に配置された第２のマイクロホン８の信号から得られる信号と、可変利得増幅器２の出力信号から得られる信号の差が無くなるまで可変利得増幅器２に第２の増幅器２０から信号が出力される可変利得増幅器２の増幅率を変化させる。
【０００６】
なお、この出願の発明に関連する先行技術文献情報としては、例えば特許文献１が知られている。
【０００７】
【特許文献１】
特開２００３−９２７６号公報
【０００８】
【発明が解決しようとする課題】
しかしながら、この従来の車載用音響再生装置を車室内に設置する場合、スピーカボックス６を設置する場所によっては、スピーカ４及び第１のマイクロホン７の前面に荷物や乗員の身体などが接近する場合がある。この場合、スピーカ４及び第１のマイクロホン７の前面空間における音響特性に変化が生じ、第１のマイクロホン７が検出する信号と第２のマイクロホン８が検出する信号との相関が崩れてしまう。このような場合、乗員の受聴点でのスピーカ再生音と騒音の混合音を擬似した信号が実際の受聴点での信号と異なることとなり、スピーカ４から再生される音と実際の騒音の大きさに異差が発生したり、最悪の場合にはスピーカ４の再生音で可変利得増幅器２の増幅率が上がっていくという異常動作に至る問題があった。
【０００９】
本発明はこの問題を解決するものであり、車室内の荷物の有無や乗員の有無に関わらず、スピーカからの再生音と騒音とから可変利得増幅器の増幅率を正確に変化させ、受聴点におけるマスキングに対して自然な補正を行う車載用音響再生装置を提供することを目的とする。
【００１０】
【課題を解決するための手段】
上記目的を達成するために、本発明は以下の構成を有するものであり、その特徴部分について列挙する。
【００１１】
本発明の請求項１に記載の発明は、車室内の騒音に応じて自動的に音量を調整する車載用音響再生装置であり、高音再生用スピーカと、中低音再生用スピーカと、前記高音再生用スピーカ近傍に設けられ、前記高音再生用スピーカからの出力音、前記中低音再生用スピーカからの出力音、および車室内の騒音との混合音を検出する第１のマイクロホンと、前記中低音再生用スピーカの近傍に設けられ、前記中低音再生用スピーカの再生音を検出する第２のマイクロホンと、前記第１のマイクロホンに接続された低域通過フィルタと、前記第２のマイクロホンに接続された増幅器と、前記低域通過フィルタに接続された第１の積分器と、前記増幅器に接続された第２の積分器と前記高音再生用スピーカと前記中低音再生用スピーカを駆動する電力増幅器に入る入力信号を自動的に調整する可変利得増幅器とを有し、前記第１のマイクロホンの出力信号は、前記低域通過フィルタで高域周波数成分を除去された後、前記第１の積分器で積分され、前記第２のマイクロホンの出力信号は、前記増幅器にて出力信号レベルを前記第１のマイクロホンの出力信号レベルと同じ大きさに調整された後、前記第２の積分器で積分され、これら積分された前記第１のマイクロホンの出力信号と前記第２のマイクロホンの出力信号とを比較し、前記第１のマイクロホンからの出力信号が大きい場合は前記可変利得増幅器の利得を上げ、前記第２のマイクロホンからの出力信号が大きい場合は前記可変利得増幅器の利得を下げる車載用音響再生装置であり、車室内の中低音再生用スピーカの再生音と車室内の騒音の混合音と、中低音再生用スピーカの再生音を検出して両者の信号を直接比較し、中低音再生用スピーカの再生音と騒音の混合音のレベルに追従して可変利得増幅器の増幅率を変化させることにより、車室内の荷物の有無や乗員の有無に関わらず受聴点における騒音のマスキングに対して自然な補正ができるという作用を有する。
【００１２】
本発明の請求項２に記載の発明は、車室内の中低音再生用スピーカの再生音と騒音の混合音を検出するための第１のマイクロホンを近傍に設置した高音再生用スピーカを、車両のインストルメントパネル上面の左右端に第１のマイクロホンと高音再生用スピーカの振動面をフロントガラス面側に向けて設置した構成としており、正確に受聴点と同等の中低音再生用スピーカの再生音と騒音の混合音を検出できるという作用を有する。
【００１３】
本発明の請求項３に記載の発明は、車室内の中低音再生用スピーカの再生音と騒音の混合音を検出するための第１のマイクロホンを近傍に設置した高音再生用スピーカを、車両の左右のフロントピラーに設置した構成を有しており、請求項２に記載の発明と同様の作用を有するとともに、車室内の定在波と反射あるいは吸音による音響特性のピークやディップを検出できるという作用を有する。
【００１４】
本発明の請求項４に記載の発明は、車室内の中低音再生用スピーカの再生音と騒音の混合音を検出するための第１のマイクロホンを近傍に設置した高音再生用スピーカを、車両の左右ドアの車室内面の上部に設置した構成を有しており、請求項３に記載の発明と同様の作用を有するとともに、中低音再生用スピーカと高音再生用スピーカが同一の車両ドアに設置されることにより、電力増幅器との配線が容易になるという効果が得られる。
【００１５】
本発明の請求項５に記載の発明は、車室内の中低音再生用スピーカの再生音と騒音の混合音を検出するための第１のマイクロホンを近傍に設置した高音再生用スピーカを、車両の左右のドアミラー部の車室内面に設置した構成を有しており、請求項４に記載の発明と同様の作用効果を有する。
【００１６】
本発明の請求項６に記載の発明は、高音再生用スピーカの近傍に配置され車室内の中低音再生用スピーカの再生音と騒音の混合音を検出するための第１のマイクロホンの信号から、車室内の定在波成分と反射あるいは吸音による音響特性のピークやディップ成分を取出すための信号処理回路と帰還制御回路を追加した構成を有しており、請求項１に記載の発明と同様の作用を有するとともに車室内の定在波の抑制と車室内の音響特性のピークやディップを自動的に補正することを可能にする作用を有する。
【００１７】
【発明の実施の形態】
以下、本発明の実施の形態について図１から図６を用いて説明する。
【００１８】
（実施の形態１）
図１は本発明の実施の形態１における車載用音響再生装置のブロック図を示す。図１において、入力端子２１に入力された信号は可変利得増幅器２２に加えられ、この可変利得増幅器２２は後述する車室内騒音と高音再生用スピーカ２６および中低音再生用スピーカ２４からの再生音の混合音に応じて生成される制御信号により制御される。可変利得増幅器２２の出力信号は電力増幅器２３に入力され、この電力増幅器２３の出力信号は車両のドアに取付けられた中低音再生用スピーカ２４と高音再生用スピーカ２６により再生される。高音再生用スピーカ２６の入力線にはコンデンサ２７が挿入されていて、このコンデンサ２７により中低域の信号が遮断され高域信号のみが高音再生用スピーカ２６に入力され再生される。高音再生用スピーカ２６の近傍には第１のマイクロホン２８が配置され、車室内の周辺の騒音と高音再生用スピーカ２６および中低音再生用スピーカ２４からの再生音の混合音を検出する。一方、車両のドアに取付けられた中低音再生用スピーカ２４の振動板２５の近傍には、第２のマイクロホン２９が配置され中低音再生用スピーカ２４の再生音を検出する。
【００１９】
高音再生用スピーカ２６の近傍に設置された第１のマイクロホン２８の出力信号の高域レベルは、高音再生用スピーカ２６に近いため受聴点に比べ高くなる。一方、中低域レベルは車両ドアに取付けられた中低音再生用スピーカ２４の振動板２５の近傍に設けられた第２のマイクロホン２９の出力信号に対し、中低音再生用スピーカ２４の距離や位置などにより定まる伝達関数に応じてレベルが下がる。この高音再生用スピーカ２６の近傍に設置された第１のマイクロホン２８の出力信号を、低域通過フィルタ３０にて高域周波数成分を遮断すると、上記２つのマイクロホン２８，２９の信号は一定のレベル差を持った相似信号と見なすことができる。
【００２０】
中低音再生用スピーカ２４の振動板２５の近傍に設けられた第２のマイクロホン２９の出力信号レベルを増幅器３２にて調整し、高音再生用スピーカ２６の近傍に設置された第１のマイクロホン２８の信号レベルと同じ大きさに調整する。高音再生用スピーカ２６の近傍に設置された第１のマイクロホン２８の出力信号は低域通過フィルタ３０で高域周波数成分を除去され第１の積分器３１で積分される。車両のドアに取付けられた中低音再生用スピーカ２４の振動板２５の近傍に設けられた第２のマイクロホン２９の出力信号は第２の積分器３３にて積分され、２つの積分された信号は比較器３４で比較される。上記２つの積分器３１，３３の出力信号差により、第１の積分器３１の出力値が大きい場合は利得制御信号発生器３５により可変利得増幅器２２の利得を上げ、第２の積分器３３の出力値が大きい場合は利得制御信号発生器３５により可変利得増幅器２２の利得を下げるように制御し、上記２つのマイクロホン２８，２９の信号の積分値が同じになるまで可変利得増幅器２２の利得を制御する。
【００２１】
車室内に騒音がない場合、上記２つのマイクロホン２８，２９の信号の積分値は同じになり可変利得増幅器２２の利得は変化しない。車室内に騒音が生じたとき、第１の積分器３１の出力値は第２の積分器３３の出力値より騒音の分だけ大きくなり、第２の積分器３３の出力値が第１の積分器３１の出力値と同じになるまで可変利得増幅器２２の利得を制御する。
【００２２】
通常、高音再生用スピーカ２６は音像を乗員の前方に定位させるために車両のハンドルの中心より上部の前方に設置するため、この高音再生用スピーカ２６の近傍に設けた第１のマイクロホン２８は荷物や乗員の身体の状態の影響を受けにくい。
【００２３】
以上のように本実施の形態１における車載用音響再生装置は、車室内の荷物の有無や乗員の有無に関わらず、車室内の騒音と中低音再生用スピーカ２４からの再生音とから自動的に制御目標値を定め、騒音の変化に追従して可変利得増幅器２２の利得を変化させることにより、受聴点におけるマスキングに対して自然な補正ができるという効果を得ることが出来る。
【００２４】
（実施の形態２）
図２は本発明の実施の形態２における車室内の中低音再生用スピーカ２４と高音再生用スピーカ２６とそれぞれの近傍に設置したマイクロホン２８，２９の位置関係を示した図である。図２において中低音再生用スピーカ２４の再生音と騒音の混合音を検出するための第１のマイクロホン２８を近傍に設置した高音再生用スピーカ２６は車両のインストルメントパネル５２の上面の左右端に配置され、振動板２５の近傍に第２のマイクロホン２９を設置した中低音再生用スピーカ２４はフロントドア５０の下部に配置される。
【００２５】
このような構成において中低音再生用スピーカ２４から再生される再生音は、中低音再生用スピーカ２４と受聴者の耳とほぼ同じ距離にある高音再生用スピーカ２６の近傍に設置された第１のマイクロホン２８で検出される。一方、車室内の騒音は狭い車室内の空間では検出する場所によるレベル差はないものとみなして良い。ゆえに車両のインストルメントパネル５２の上面に設置した第１のマイクロホン２８で検出される車室内の騒音と中低音再生用スピーカ２４の再生音の混合音は、高音再生用スピーカ２６の再生音を除くと受聴者の耳の位置での車室内騒音と中低音再生用スピーカ２４の再生音の混合音と同等となり、この信号を用いて可変利得増幅器２２の利得を制御することで違和感のない自然な制御を可能とする。
【００２６】
（実施の形態３）
図３は本発明の実施の形態３における車室内の中低音再生用スピーカ２４と高音再生用スピーカ２６とそれぞれの近傍に設置したマイクロホン２８，２９の位置関係を示した図である。図３において、中低音再生用スピーカ２４の再生音と騒音の混合音を検出するための第１のマイクロホン２８を近傍に設置した高音再生用スピーカ２６は車室内のフロントピラー５１に、フロントドア５０の下部に配置された振動板２５の近傍に第２のマイクロホン２９を設置した中低音再生用スピーカ２４の取付け面と第１のマイクロホン２８の検出面が平行になるように取付けられている。
【００２７】
第１のマイクロホン２８で検出される車室内の騒音と中低音再生用スピーカ２４の再生音の混合音と受聴者の耳の位置での車室内の騒音と中低音再生用スピーカ２４の再生音の混合音との関係は実施の形態２と同様である。さらに第１のマイクロホン２８がフロントドア５０の下部に配置された中低音再生用スピーカ２４の取付け面と向かい合った構成となるため、向かい合った面の距離に対応した波長の１／２や１／４の定在波を検出することが可能となる。更に車室内の左右両端の面により近づくことで、反射や吸音の影響を受けやすくなり音響特性のピークやディップの検出も可能となる。
【００２８】
（実施の形態４）
図４は本発明の実施の形態４における車室内の中低音再生用スピーカ２４と高音再生用スピーカ２６とそれぞれの近傍に設置したマイクロホン２８、２９の位置関係を示した図である。図４において中低音再生用スピーカ２４の再生音と騒音の混合音を検出するための第１のマイクロホン２８を近傍に設置した高音再生用スピーカ２６は、車両の左右フロントドア５０の車室内面の上部に、フロントドア５０の下部に配置された振動板２５の近傍に第２のマイクロホン２９を設置した中低音再生用スピーカ２４の取付け面と第１のマイクロホン２８の検出面が平行になるように取付けられている。
【００２９】
実施の形態３と同様の効果を有するとともに、上記２つのスピーカ２４，２６を同じフロントドア５０に配置することでスピーカの配線が容易にできるという効果も得られる。
【００３０】
（実施の形態５）
図５は本発明の実施の形態５における車室内の中低音再生用スピーカ２４と高音再生用スピーカ２６とそれぞれの近傍に設置したマイクロホン２８，２９の位置関係を示した図である。図５において中低音再生用スピーカ２４の再生音と騒音の混合音を検出するための第１のマイクロホン２８を近傍に設置した高音再生用スピーカ２６は車両の左右のドアミラー部５４の車室内面に、フロントドア５０の下部に配置された振動板２５の近傍に第２のマイクロホン２９を設置した中低音再生用スピーカ２４の取付け面と第１のマイクロホン２８の検出面が平行になるように取付けられている。効果については実施の形態４と同様である。
【００３１】
（実施の形態６）
図６は本発明の実施の形態６におけるブロック図を示す。本発明の実施の形態１と異なるところは、高音再生用スピーカ２６の近傍に配置され、車室内の中低音再生用スピーカ２４の再生音と騒音の混合音を検出するための第１のマイクロホン２８の信号から車室内の定在波成分と反射あるいは吸音による音響特性のピークやディップ成分を取出すための信号処理回路３７と、減算器３６および演算増幅器３８からなる帰還制御回路を追加した構成となっている。
【００３２】
実施の形態３から５で述べたように、中低音再生用スピーカ２４の再生音と騒音の混合音を検出するための第１のマイクロホン２８を近傍に設置した高域再生用スピーカ２６を配置すると車室内の定在波と反射および吸音による音響特性のピークやディップが検出される。この第１のマイクロホン２８の信号から信号処理回路３７により定在波とピーク成分やディップ成分を取出し、可変利得増幅器２２の前段に設けた減算器３６に帰還させることで自動的に車室内の定在波と音響特性のピークやディップを補正できるという効果を有するものである。
【００３３】
【発明の効果】
以上のように、本発明は車室内の荷物の有無や乗員の有無に関わらず、中低音再生用スピーカからの再生音と騒音とから可変利得増幅器の増幅率を正確に変化させ、受聴点におけるマスキングに対して自然な補正を行うことができる車載用音響再生装置を提供するものである。
【図面の簡単な説明】
【図１】本発明の実施の形態１における車載用音響再生装置を示すブロック図
【図２】同実施の形態２のスピーカとマイクロホンの位置関係を示す図
【図３】同実施の形態３のスピーカとマイクロホンの位置関係を示す図
【図４】同実施の形態４のスピーカとマイクロホンの位置関係を示す図
【図５】同実施の形態５のスピーカとマイクロホンの位置関係を示す図
【図６】同実施の形態６における車載用音響再生装置を示すブロック図
【図７】従来の車載用音響再生装置を示すブロック図
【符号の説明】
２１入力端子
２２可変利得増幅器
２３電力増幅器
２４中低音再生用スピーカ
２５振動板
２６高音再生用スピーカ
２７コンデンサ
２８第１のマイクロホン
２９第２のマイクロホン
３０低域通過フィルタ
３１第１の積分器
３２増幅器
３３第２の積分器
３４比較器
３５利得制御信号発生器
３６減算器
３７信号処理回路
３８演算増幅器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an in-vehicle reproduction apparatus for automatically correcting a change in acoustic characteristics in a vehicle interior due to a running state of an automobile and obtaining a good speaker reproduction sound.
[0002]
[Prior art]
FIG. 7 shows a block diagram of a conventional on-vehicle sound reproducing device that corrects an output level reproduced from a speaker in accordance with fluctuations in ambient noise level. In the figure, the signal input from the input terminal 1 passes through the variable gain amplifier 2 that changes the amplification factor of the input signal, is amplified by the power amplifier 3, and is reproduced by the speaker 4 in the speaker box 6.
[0003]
The signal of the first microphone 7 arranged around the speaker box 6 and the signal of the second microphone 8 arranged inside the speaker box 6 have the same lowest resonance frequency (f ₀ ). The low-pass filter 9 and the first high-pass filter 10 are input to the operational amplifier 11. By matching the lowest resonance frequency of the first low-pass filter 9 and the first high-pass filter 10 (f ₀₎ to the minimum resonance frequency of the speaker 4 (f _0), a first low-pass filter 9 The output characteristics of the first high-pass filter 10 are substantially the same band-pass characteristics with respect to frequency, and the phase is opposite. The output signals of the first low-pass filter 9 and the first high-pass filter 10 are calculated by the operational amplifier 11, and the reproduced sound of the speaker 4 is reduced from the output signal of the first low-pass filter 9. This simulates the mixed sound of the reproduction sound and noise of the speaker 4 at the listening point. Then, the first amplifier 12 is adjusted so as to have the same magnitude as the output signal of the variable gain amplifier 2.
[0004]
On the other hand, the output signal of the variable gain amplifier 2 is adjusted by the second low-pass filter 15 and the second high-pass filter 16 to the same band pass characteristic as the output characteristic of the operational amplifier 11 when there is no noise.
[0005]
The two signals are converted into positive and negative absolute values by the first absolute value circuit 13 and the second absolute value circuit 17, respectively, and integrated by the first integrator 14 and the second integrator 18. . The integrated positive and negative absolute value signals are added by an adder 19 so that the difference between the two signals is compared and a signal for changing the amplification factor of the variable gain amplifier 2 from the second amplifier 20 is variable gain. It is output to the amplifier 2. Then, a signal obtained from the signals of the first microphone 7 arranged around the speaker box 6 and the second microphone 8 arranged inside the speaker box 6 and a signal obtained from the output signal of the variable gain amplifier 2 The gain of the variable gain amplifier 2 from which the signal is output from the second amplifier 20 is changed to the variable gain amplifier 2 until the difference is eliminated.
[0006]
For example, Patent Document 1 is known as prior art document information related to the invention of this application.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 2003-9276
[Problems to be solved by the invention]
However, when this conventional in-vehicle sound reproducing device is installed in the vehicle interior, depending on the location where the speaker box 6 is installed, luggage or the body of an occupant may approach the front surface of the speaker 4 and the first microphone 7. is there. In this case, the acoustic characteristics in the front space of the speaker 4 and the first microphone 7 change, and the correlation between the signal detected by the first microphone 7 and the signal detected by the second microphone 8 is lost. In such a case, the signal simulating the mixed sound of the speaker reproduction sound and noise at the occupant's listening point is different from the signal at the actual listening point, and the sound reproduced from the speaker 4 and the actual noise level are different. In the worst case, the gain of the variable gain amplifier 2 is increased by the reproduced sound of the speaker 4.
[0009]
The present invention solves this problem. Regardless of the presence or absence of luggage in the passenger compartment or the presence or absence of passengers, the amplification factor of the variable gain amplifier is accurately changed from the reproduced sound and noise from the speaker, so that It is an object of the present invention to provide an on-vehicle sound reproducing device that performs natural correction for masking.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration, and its characteristic parts are listed.
[0011]
The invention according to claim 1 of the present invention is an on-vehicle sound reproduction device that automatically adjusts the volume according to noise in the vehicle interior, and includes a high-frequency sound reproduction speaker, a mid-low-frequency sound reproduction speaker, and the high-frequency sound reproduction device. A first microphone provided in the vicinity of the speaker for detecting a mixed sound of an output sound from the high sound reproduction speaker, an output sound from the medium / low sound reproduction speaker, and a vehicle interior noise; and the medium / low sound reproduction A second microphone that is provided in the vicinity of the speaker for detecting the reproduction sound of the middle / low sound reproduction speaker, a low-pass filter that is connected to the first microphone, and a second microphone that is connected to the second microphone An amplifier, a first integrator connected to the low-pass filter, a second integrator connected to the amplifier, the high-frequency sound reproduction speaker, and the middle-low sound reproduction speaker A variable gain amplifier that automatically adjusts an input signal entering the amplifier, and the output signal of the first microphone is subjected to the first integration after the high-frequency component is removed by the low-pass filter. And the output signal level of the second microphone is adjusted to the same level as the output signal level of the first microphone by the amplifier, and then integrated by the second integrator. And comparing the integrated output signal of the first microphone and the output signal of the second microphone, and if the output signal from the first microphone is large, increasing the gain of the variable gain amplifier, wherein when the output signal from the second microphone is large is vehicle audio reproducing apparatus to reduce the gain of the variable gain amplifier, the reproduced sound of the low-frequency sound reproducing speaker in the car compartment and passenger compartment The mixed sound of the noise and the reproduction sound of the middle / low frequency reproduction speaker are detected and directly compared, and the level of the mixed sound of the reproduction sound and noise of the middle / low frequency reproduction speaker is tracked. By changing the amplification factor, a natural correction can be made for noise masking at the listening point regardless of the presence or absence of luggage in the passenger compartment or the presence or absence of passengers.
[0012]
According to a second aspect of the present invention, there is provided a high sound reproduction speaker in which a first microphone for detecting a mixed sound of a reproduction sound and a noise of a middle / low sound reproduction speaker in a vehicle interior is installed in the vicinity of the vehicle. The first microphone and the vibration surface of the high-frequency sound reproduction speaker are installed on the left and right edges of the top surface of the instrument panel with the windshield surface facing the windshield surface. It has the effect that a mixed sound of noise can be detected.
[0013]
According to a third aspect of the present invention, there is provided a high sound reproduction speaker in which a first microphone for detecting a mixed sound of a reproduction sound and a noise of a medium / low sound reproduction speaker in a vehicle interior is installed in the vicinity of the vehicle. It has a configuration installed on the left and right front pillars, has the same effect as the invention of claim 2, and can detect peaks and dips of acoustic characteristics due to standing waves and reflection or sound absorption in the passenger compartment. Has an effect.
[0014]
According to a fourth aspect of the present invention, there is provided a high sound reproduction speaker in which a first microphone for detecting a mixed sound of reproduced sound and noise of a medium / low sound reproduction speaker in a vehicle interior is installed in the vicinity of the vehicle. It has the structure installed in the upper part of the vehicle interior surface of the left and right doors, and has the same operation as that of the invention according to claim 3, and the middle and low tone reproduction speakers are installed in the same vehicle door. By doing so, the effect that wiring with a power amplifier becomes easy is acquired.
[0015]
According to a fifth aspect of the present invention, there is provided a high sound reproduction speaker in which a first microphone for detecting a mixed sound of a reproduction sound and a noise of a medium / low sound reproduction speaker in a vehicle interior is installed in the vicinity of the vehicle. It has the structure installed in the vehicle interior surface of the left-right door mirror part, and has the same effect as the invention of Claim 4.
[0016]
The invention according to claim 6 of the present invention is based on the signal from the first microphone for detecting the mixed sound of the reproduction sound and the noise of the middle / low sound reproduction speaker arranged in the vicinity of the high sound reproduction speaker. A signal processing circuit and a feedback control circuit for extracting a standing wave component in a vehicle interior and a peak or dip component of acoustic characteristics due to reflection or sound absorption are added, and the configuration is the same as that of the invention according to claim 1. It has the effect of suppressing the standing wave in the passenger compartment and automatically correcting the peak and dip of the acoustic characteristics in the passenger compartment.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0018]
(Embodiment 1)
FIG. 1 is a block diagram of an in-vehicle sound reproducing device according to Embodiment 1 of the present invention. In FIG. 1, a signal input to an input terminal 21 is applied to a variable gain amplifier 22, and this variable gain amplifier 22 is used to generate vehicle interior noise and a reproduced sound from a high sound reproduction speaker 26 and a medium / low sound reproduction speaker 24 described later. It is controlled by a control signal generated according to the mixed sound. The output signal of the variable gain amplifier 22 is input to a power amplifier 23, and the output signal of the power amplifier 23 is reproduced by a medium / low sound reproduction speaker 24 and a high sound reproduction speaker 26 attached to a vehicle door. A capacitor 27 is inserted in the input line of the high-frequency sound reproduction speaker 26, and the low-frequency signal is cut off by the capacitor 27, and only the high-frequency signal is input to the high-frequency sound reproduction speaker 26 and reproduced. A first microphone 28 is disposed in the vicinity of the high sound reproduction speaker 26 to detect a mixed sound of ambient noise in the vehicle interior and reproduction sound from the high sound reproduction speaker 26 and the medium / low sound reproduction speaker 24. On the other hand, a second microphone 29 is disposed in the vicinity of the diaphragm 25 of the medium / low sound reproduction speaker 24 attached to the door of the vehicle to detect the reproduction sound of the medium / low sound reproduction speaker 24.
[0019]
The high level of the output signal of the first microphone 28 installed in the vicinity of the high sound reproduction speaker 26 is close to the high sound reproduction speaker 26 and thus becomes higher than the listening point. On the other hand, the mid-low range level is the distance and position of the mid-low sound reproduction speaker 24 with respect to the output signal of the second microphone 29 provided in the vicinity of the diaphragm 25 of the mid-low sound reproduction speaker 24 attached to the vehicle door. The level decreases according to the transfer function determined by the above. When the output signal of the first microphone 28 installed in the vicinity of the high sound reproduction speaker 26 is blocked by the low-pass filter 30, the signals of the two microphones 28 and 29 have a certain level. It can be regarded as a similar signal with a difference.
[0020]
The output signal level of the second microphone 29 provided in the vicinity of the diaphragm 25 of the middle / low sound reproduction speaker 24 is adjusted by the amplifier 32, and the first microphone 28 installed in the vicinity of the high sound reproduction speaker 26 is adjusted. Adjust to the same size as the signal level. The output signal of the first microphone 28 installed in the vicinity of the high sound reproduction speaker 26 is removed by the low-pass filter 30 and is integrated by the first integrator 31. The output signal of the second microphone 29 provided in the vicinity of the diaphragm 25 of the medium / low sound reproduction speaker 24 attached to the vehicle door is integrated by the second integrator 33, and the two integrated signals are obtained. Comparison is performed by the comparator 34. When the output value of the first integrator 31 is large due to the difference between the output signals of the two integrators 31 and 33, the gain of the variable gain amplifier 22 is increased by the gain control signal generator 35, and the second integrator 33 When the output value is large, the gain control signal generator 35 controls the gain of the variable gain amplifier 22 to decrease, and the gain of the variable gain amplifier 22 is increased until the integrated values of the signals of the two microphones 28 and 29 become the same. Control.
[0021]
When there is no noise in the passenger compartment, the integrated values of the signals of the two microphones 28 and 29 are the same, and the gain of the variable gain amplifier 22 does not change. When noise occurs in the passenger compartment, the output value of the first integrator 31 is larger than the output value of the second integrator 33 by the amount of noise, and the output value of the second integrator 33 is the first integration value. The gain of the variable gain amplifier 22 is controlled until the output value of the amplifier 31 becomes the same.
[0022]
Usually, the high sound reproduction speaker 26 is installed in front of the center of the handle of the vehicle so as to localize the sound image in front of the occupant. Therefore, the first microphone 28 provided in the vicinity of the high sound reproduction speaker 26 is a luggage. And is not easily affected by the condition of the passenger's body.
[0023]
As described above, the on-vehicle sound reproduction device according to the first embodiment automatically uses the vehicle interior noise and the reproduced sound from the middle / low sound reproduction speaker 24 regardless of the presence or absence of luggage or the presence of passengers. By setting the control target value and changing the gain of the variable gain amplifier 22 following the change in noise, it is possible to obtain an effect that natural correction can be performed for masking at the listening point.
[0024]
(Embodiment 2)
FIG. 2 is a diagram showing the positional relationship between the middle / low sound reproduction speaker 24 and the high sound reproduction speaker 26 and the microphones 28 and 29 installed in the vicinity of the vehicle interior according to the second embodiment of the present invention. In FIG. 2, the high sound reproduction speaker 26 in which the first microphone 28 for detecting the mixed sound of the reproduction sound and the noise of the medium / low sound reproduction speaker 24 is installed in the vicinity is provided on the left and right ends of the upper surface of the instrument panel 52 of the vehicle. The middle / low-pitched sound reproduction speaker 24 that is disposed and has the second microphone 29 disposed in the vicinity of the diaphragm 25 is disposed below the front door 50.
[0025]
In such a configuration, the reproduced sound reproduced from the medium / low sound reproduction speaker 24 is a first sound installed in the vicinity of the high / low sound reproduction speaker 26 at approximately the same distance as the medium / low sound reproduction speaker 24 and the listener's ear. It is detected by the microphone 28. On the other hand, the noise in the vehicle interior may be regarded as having no level difference depending on where it is detected in a narrow vehicle interior space. Therefore, the mixed sound of the vehicle interior noise detected by the first microphone 28 installed on the upper surface of the instrument panel 52 of the vehicle and the reproduction sound of the middle / low sound reproduction speaker 24 excludes the reproduction sound of the high sound reproduction speaker 26. And the mixed sound of the vehicle interior noise at the position of the listener's ear and the reproduced sound of the middle / low sound reproducing speaker 24, and by using this signal to control the gain of the variable gain amplifier 22, there is no sense of incongruity. Allows control.
[0026]
(Embodiment 3)
FIG. 3 is a diagram showing the positional relationship between the middle / low sound reproducing speaker 24 and the high sound reproducing speaker 26 and the microphones 28 and 29 installed in the vicinity of the vehicle interior according to the third embodiment of the present invention. In FIG. 3, a high sound reproduction speaker 26 in which a first microphone 28 for detecting a mixed sound of the reproduction sound and noise of the medium / low sound reproduction speaker 24 is installed in the vicinity of the front pillar 51 in the vehicle interior and the front door 50. Are attached so that the mounting surface of the speaker for medium / low sound reproduction 24 in which the second microphone 29 is installed in the vicinity of the diaphragm 25 arranged in the lower part of the first microphone 28 and the detection surface of the first microphone 28 are parallel to each other.
[0027]
The mixed sound of the vehicle interior noise detected by the first microphone 28 and the reproduction sound of the middle / low sound reproduction speaker 24, the vehicle interior noise at the position of the listener's ear and the reproduction sound of the middle / low sound reproduction speaker 24 The relationship with the mixed sound is the same as in the second embodiment. Further, since the first microphone 28 is configured to face the mounting surface of the mid / low-pitched sound reproduction speaker 24 disposed at the lower part of the front door 50, the wavelength of the wavelength corresponding to the distance of the facing surface is ½ or ¼. It is possible to detect standing waves. Furthermore, by approaching the left and right end surfaces of the vehicle interior, it is easy to be affected by reflection and sound absorption, and the peak and dip of the acoustic characteristics can be detected.
[0028]
(Embodiment 4)
FIG. 4 is a diagram showing the positional relationship between the middle / low sound reproduction speaker 24 and the high sound reproduction speaker 26 and microphones 28 and 29 installed in the vicinity of the vehicle interior according to the fourth embodiment of the present invention. In FIG. 4, the high sound reproduction speaker 26 in which the first microphone 28 for detecting the mixed sound of the reproduction sound and the noise of the medium / low sound reproduction speaker 24 is installed in the vicinity of the vehicle interior surface of the left and right front doors 50 of the vehicle. In the upper part, the mounting surface of the middle / low sound reproducing speaker 24 in which the second microphone 29 is installed in the vicinity of the diaphragm 25 disposed at the lower part of the front door 50 and the detection surface of the first microphone 28 are parallel to each other. Installed.
[0029]
In addition to the same effects as those of the third embodiment, arranging the two speakers 24 and 26 on the same front door 50 also provides an effect that the wiring of the speakers can be easily performed.
[0030]
(Embodiment 5)
FIG. 5 is a diagram showing the positional relationship between the middle / low sound reproduction speaker 24 and the high sound reproduction speaker 26 and microphones 28 and 29 installed in the vicinity of the vehicle interior according to the fifth embodiment of the present invention. In FIG. 5, the high sound reproduction speaker 26 in which the first microphone 28 for detecting the mixed sound of the reproduction sound and the noise of the middle / low sound reproduction speaker 24 is installed in the vicinity is provided on the vehicle interior surface of the left and right door mirror portions 54 of the vehicle. The mounting surface of the middle / low sound reproducing speaker 24 in which the second microphone 29 is installed in the vicinity of the diaphragm 25 disposed at the lower part of the front door 50 and the detection surface of the first microphone 28 are mounted in parallel. ing. The effect is the same as in the fourth embodiment.
[0031]
(Embodiment 6)
FIG. 6 shows a block diagram in the sixth embodiment of the present invention. A difference from the first embodiment of the present invention is that the first microphone 28 is arranged in the vicinity of the high sound reproduction speaker 26 and detects the mixed sound of the reproduction sound and the noise of the medium / low sound reproduction speaker 24 in the vehicle interior. The signal processing circuit 37 for extracting the standing wave component in the vehicle interior, the peak of the acoustic characteristic due to reflection or sound absorption, and the dip component from the above signal, and the feedback control circuit comprising the subtractor 36 and the operational amplifier 38 are added. ing.
[0032]
As described in the third to fifth embodiments, when the high frequency reproduction speaker 26 in which the first microphone 28 for detecting the mixed sound of the reproduction sound and the noise of the medium / low sound reproduction speaker 24 is installed is disposed. Peaks and dips in acoustic characteristics due to standing waves, reflections and sound absorption in the passenger compartment are detected. A standing wave, a peak component, and a dip component are extracted from the signal of the first microphone 28 by the signal processing circuit 37, and are automatically fed back to the subtractor 36 provided in the preceding stage of the variable gain amplifier 22 to automatically determine the interior of the vehicle interior. This has the effect of correcting the peak and dip of the standing wave and the acoustic characteristics.
[0033]
【The invention's effect】
As described above, the present invention accurately changes the amplification factor of the variable gain amplifier from the reproduction sound and noise from the middle / low sound reproduction speaker regardless of the presence or absence of luggage in the passenger compartment or the presence or absence of a passenger, and at the listening point. It is an object of the present invention to provide an in-vehicle sound reproducing apparatus capable of performing natural correction for masking.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an in-vehicle sound reproducing device according to Embodiment 1 of the present invention. FIG. 2 is a diagram showing a positional relationship between a speaker and a microphone according to Embodiment 2. FIG. FIG. 4 is a diagram showing the positional relationship between the speaker and the microphone. FIG. 4 is a diagram showing the positional relationship between the speaker and the microphone according to the fourth embodiment. FIG. 5 is a diagram showing the positional relationship between the speaker and the microphone according to the fifth embodiment. FIG. 7 is a block diagram showing a vehicle-mounted sound reproducing device according to the sixth embodiment. FIG. 7 is a block diagram showing a conventional vehicle-mounted sound reproducing device.
21 Input terminal 22 Variable gain amplifier 23 Power amplifier 24 Medium / low sound reproduction speaker 25 Diaphragm 26 High sound reproduction speaker 27 Capacitor 28 First microphone 29 Second microphone 30 Low-pass filter 31 First integrator 32 Amplifier 33 Second integrator 34 Comparator 35 Gain control signal generator 36 Subtractor 37 Signal processing circuit 38 Operational amplifier

Claims

It is an in-vehicle sound reproduction device that automatically adjusts the volume according to the noise in the passenger compartment,
A speaker for high-pitched sound reproduction;
A mid-low range speaker,
A first microphone that is provided in the vicinity of the high-frequency sound reproduction speaker and detects a mixed sound of the output sound from the high-frequency sound reproduction speaker, the reproduction sound from the medium-low sound reproduction speaker, and the vehicle interior noise;
A second microphone provided in the vicinity of the middle / low sound reproduction speaker and detecting a reproduction sound of the middle / low sound reproduction speaker;
A low pass filter connected to the first microphone;
An amplifier connected to the second microphone;
A first integrator connected to the low pass filter;
A second integrator connected to the amplifier;
A variable gain amplifier that automatically adjusts an input signal that enters a power amplifier that drives the high-pitched sound reproduction speaker and the mid-low sound reproduction speaker;
The output signal of the first microphone is integrated by the first integrator after the high-frequency component is removed by the low-pass filter,
The output signal of the second microphone is adjusted by the amplifier to have the same output signal level as the output signal level of the first microphone, and then integrated by the second integrator.
The integrated output signal of the first microphone and the output signal of the second microphone are compared, and when the output signal from the first microphone is large, the gain of the variable gain amplifier is increased, and the first A vehicle-mounted sound reproduction device that reduces the gain of the variable gain amplifier when the output signal from the microphone of 2 is large .

The in-vehicle use according to claim 1, wherein the high sound reproduction speaker is installed on left and right ends of an upper surface of an instrument panel of a vehicle with a vibration surface of the first microphone and the high sound reproduction speaker facing a windshield surface. Sound playback device.

The in-vehicle sound reproducing device according to claim 1, wherein the high sound reproducing speaker is installed on left and right front pillars of a vehicle.

The on- vehicle sound reproduction device according to claim 1, wherein the high-frequency sound reproduction speaker is installed on an upper portion of a vehicle interior surface of the left and right doors of the vehicle.

The in-vehicle sound reproducing apparatus according to claim 1, wherein the high-frequency sound reproducing speaker is installed on a vehicle interior surface of the left and right door mirror portions of the vehicle.

A subtractor is further provided in front of the variable gain amplifier,
Detecting a peak component and a dip component of said first acoustic characteristics from the microphone signal by a standing wave and the reflection or sound absorption in the vehicle interior, these by feeding back to the subtracter, the standing wave, the peak and dip The in-vehicle sound reproducing apparatus according to claim 1, wherein the input characteristics of the power amplifier are automatically corrected so as to be eliminated.