Monday, September 26, 2011

Active Sonar and Passive Sonar - アクティブ・ソナーとパッシブ・ソナー

When Daniel applies echolocation to human use, he mentions the difference between 'active sonar' and 'passive sonar' for.'

What he calls 'passive sonar' is the sound produced by someone or something else. Though this kind of sounds give general feedback on what is happening around us, but it does not give precise feedback on things around us, like the distance, size and the type of material.

Whereas, what he calls 'active sonar' is the effective way to find out what is ahead, as you control the sound by producing it by yourself and hear the echo.

But what if we are in noisy environment? - He answers in his literature that we should be able to determine our own tongue click from others since we control the click sound... in flash sonar, he recommends we practice distinguishing our own tongue click sound from others by clicking to the wall and hear the sound, which he calls the process 'hook stimulus' so we will get to hear our own click sound regardless of the environment.

His term of 'active sonar' seem to include other sounds made by ourselves, like a tapping cane sound or a clap of hand. Though cane tapping and hand clapping may help us understand what is around, Daniel says it does not give us feedback for determining the distance, the size, and the material of the object.
Moreover, cane tapping sound is made too far from our ears, so as hand clapping. if clapping hands right in front of face, we won:t hear the echo.

Therefore, Daniel believes his 'flash sonar' with hearing the echo of our own tongue click works better than other audio feedbacks available around us.

Though he did not say this, I think he uses his flash sonar technique when passive sonar does not give enough information, and I would like to confirm that by meeting him in person... soon!






しかし、雑踏の中などで、どうやって自分の舌打ち音の反響を聞き分けられるか、それはダニエルが「フラッシュ・ソナー」を教える際、始めに壁などの前で、自分の舌打ち音を実際に聞いて覚える、「hook stimulus」という訓練を繰り返し行います。これにより、自分の舌打ち音を、他の音と区別することができるようになるそうです。



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