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Where the real low volume sound goes(disappears) when you speak through microphone?I am meaning we are only hearing the increased voice by microphone through speaker for example in a auditorium.

Why do we hear microphone raised voice instead of our low volume voice?Where the low volume sound (real) goes?

My idea is they are in the same phase because the electric and sound goes very fast from cables.So they bind together with an infinitely little error that can be omitted.

closed as unclear what you're asking by Rory Alsop Sep 27 '16 at 9:07

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    I don't understand the question – Andy aka Sep 22 '16 at 23:06
  • We have a voice.When we are speaking to someone they hear our bare voice.Suppose it is 5 db.When you talk through mic the processed sound is 35 db again suppose.So do we hear both processed and bare voice same time resulting in volume increase that comes as a one source sound. – aintnosunshinewhenyouaregone Sep 22 '16 at 23:09
  • Do they bind together the sound coming through my mouth and the sound coming through mic to speaker? – aintnosunshinewhenyouaregone Sep 22 '16 at 23:10
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    Sounds mix together in the air. The direct sound from the speaker's mouth and the sound from the speakers are mixed together. The sound from the speakers is just generally so much louder than the direct sound that it tends to mask the direct sound. – Linuxios Sep 23 '16 at 3:28
  • @Linuxios why don't you turn that comment into an answer ? – audionuma Sep 23 '16 at 7:35
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You can boost the gain on a microphone signal so that is is much more sensitive than your ears. HOWEVER, you cannot make a microphone that has similar "automatic noise rejection" that your ear-brain system uses. Microphones don't hear sound like our ears do. If you try to amplify soft speaking, you will also be unavoidably amplifying the ambient noise along with it.

This is bad enough when trying to simply record soft voices. But it is even more of an issue when trying to amplify speech in a room (auditorium, etc.) because you are amplifying the ambient noise (including the sound system itself) you will quickly encounter feedback where the sounds from the speaker enter the microphone and cause a loud howling sound. This is why you frequently encounter inadequate sound reinforcement in this situation.

This has nothing to do with "phases" or cables, etc. It is an effect of acoustic physics and the Inverse-Square Law.

Ref:

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If I understand your question correctly, you are asking as to why what you hear from a microphone recording or PA System does not sound like the original voice.

There are many reasons, but the most important is that the equipment is actually changing the sound. The microphones, the amplifiers, and the speakers, all have an effect on the sound. Even the best equipment leaves some impact.

In the case of human voice (recorded in a quiet setting), there are a few major factors.

1) Microphone frequency response.

Microphones are not as sensitive to some frequencies as they are others. This means that some microphones might make high pitched sounds seem much louder than low pitched sounds, even if they really should have been at the same volume.

2) Distortion, coloration, or noise from the amplification unit.

When you record something, or when you speak over a PA system, the signal needs to be amplified somehow. This process will usually add 'harmonics' and 'distortion' that result in the nature of the sound changing. Think of the sound of a typical electric guitar solo, compared to when the guitar is unplugged. This is an example of extreme coloration and distortion from an amplifier designed to add as much character as possible. Amplifiers for recording are usually designed to add as little coloration as possible. The good ones are expensive though, and still change the sound a little.

3) Frequency response of the speakers.

Just like how microphones have a frequency response curve, so do speakers. This means that some speakers will make high pitched sounds louder than low pitched ones, and visa-versa for others. Good quality professional speakers (called monitors) will try to make all sounds equally loud. Some cheaper ones might try to make the bass extra loud, in order to be 'cool'. You've probably seen that you can adjust the bass/treble ratio on most stereo sets, this is to compensate for the limited accuracy of frequency response, and allows you to change it to your preferences.

One other thing. You may notice voice recordings of other people sound closer to the original than recordings of your own voice. You might think that it's just your imagination, or that you have somehow recorded the voice wrong, but that's probably not it. It's actually because you don't hear your own voice the way other people do! When you speak, the sound moves through your bones and into your ear directly in addition to the sound from the air. This means you get a huge amount of bass frequencies and some additional harmonics that are very different from what you hear from the air. That means the microphone, and everybody else, actually hears something different from what the person speaking hears.

There are a few techniques for trying to emulate this effect though. Like trying to put the microphone closer to your chest, or adding some reverb with a low-pass filter. The room and microphone type also can matter here... The closest I ever got to matching what I perceive my own voice to be, was when I setup an omni-mic in a very narrow but long storage closet, and spoke into the air above the microphone. The result was surprisingly close to what I hear when I speak, and very different from what I get when I do this in a plain old room with no special treatment.

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