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High quality microphone for distance application

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aminpix

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I am more digital person so please bear with me for these basic questions.

I am designing a board with a microphone array. The goal is to use high quality microphones and connect them to tlv320adc6140 to convert microphone output to digital and the rest of the board will be done in digital (tlv320adc6140 accept both microphone and line-in).
I am looking for a high quality microphone for my board.

1- Any high quality microphone do you recommend for my application?
(This microphone array supposed to be use for outdoor application to hear far voices.)

2- Should I use amplifier after microphone?
(tlv320adc6140 has input mic-in, Since we use it in open area, we may have some load sounds closer to the microphone. I think using amplifier may boost far sounds but it will boos load near sounds as well)
 
How do you define "high quality". I could suggest a Neumann N49 microphone. It's "high quality" and about US$9000. Is that what you want?

I could suggest a Shure M58. It's kind of a standard microphone and about US$100. Is that good enough?

But the fact that this needs to be outdoors is a whole other requirement. Does it have to be weatherproof? Omni-directional? Directional? Cost? Sensitivity?

Nobody can answer whether you need an amp or not. What's the audio level? What's the microphone sensitivity?
And there's no question about whether an amplifier "may" boost near sounds. It most certainly will.

You need some requirements before anyone can answer your questions.
 
Hi,

1) We have no clue. Neither frequency range, waveform, generated signal level, distance to signal source, expected performance...
It´s on you to define the application´s specifications.

2) It depends on used microphone, it´s output level and the signal input range of the ADC.
It´s on you to define the application´s specifications.

***
Amplifiers amplify the input signal. They can´t differentiate between far and near.

****
Each microphone has a directional characteristic. If you define the wanted characteristic first you can search for according microphones.

****
If I had the job to "hear far voices" (without any other requirements) ... I´d surely use a parabolic mirror on the microphone.


Klaus
 
barry said:
How do you define "high quality". I could suggest a Neumann N49 microphone. It's "high quality" and about US$9000. Is that what you want?

I could suggest a Shure M58. It's kind of a standard microphone and about US$100. Is that good enough?

But the fact that this needs to be outdoors is a whole other requirement. Does it have to be weatherproof? Omni-directional? Directional? Cost? Sensitivity?

Nobody can answer whether you need an amp or not. What's the audio level? What's the microphone sensitivity?
And there's no question about whether an amplifier "may" boost near sounds. It most certainly will.

You need some requirements before anyone can answer your questions.
Click to expand...
I understands my question was too fuzzy. Unfortunately, I don't have enough knowledge of sounds and microphones.
let me ask my question in this way:
I am looking for a microphone or circuit to record normal human conversation in outdoor from 30 to 50 meter. Do you suggest any microphone?
I have noticed there are some SNR and sensitivity. what range on sensitivity I should look for?
 
Hi,

aminpix said:
I don't have enough knowledge of sounds and microphones.
Click to expand...
It´s your project. So tell us in technical terms (not microphone related, not sound related) what you want to achieve.

In your first post you talk about a microphone array. How many? How are they physically arranged?
How do you "connect" them? With "connect" I mean the algorithm on the digital side.
What is your idea? You say you are a digital guy. If you want to write code ... you first need a strategy.

****
High quality microphone.
There are many qualities for a microphone, like: dynamic, bandwidth, frequency flatness, impulse reponse...

What we don´t know: how important is the "sound quality" really. Is it for high perfomance audio productions? Or just to clearly understand the spoken words?

*****
aminpix said:
The goal is to use high quality microphones
Click to expand...
I like to contradict. I can´t imagine the goal is "to use high quality microphones".
I rather guess you want a high quality result (how ever you define your result) ... with rather cheap microphones, but with features that allow the high quality result.
I understand that using "high quality microphones" may exclude some problems ... but you buy this with a lot of money. And maybe there are much cheaper microphones giving the same result.
What I want to say: you need to focus on the result. You need to define the result .... and then .. with the next step .. you need to focus on how to achieve this result.

***
See it like this:
If you want to transport a parcel from A to B very fast. Then you may buy a Lambourghini, because it is fast. But what does the Labourghini help if the parcel is too big for the boot? Or there is water between A and B.

****
What is an array of microphones? 3 x 3 = 9? 10 x 10 = 100? 32 x 32 x 1024?

Klaus
 
Any old Sony 7" reel tape recorder from the 60's used magnetic mics $10 (used if you can find one) will pick up distant sounds better than your ears if you use stereo. But it will not have the compression of your ears, so use a compressor or fast attack slow decay AGC or a compander in software.

Using small parabolic dish will make it a narrower beam. For the ultimate 100m range use an array of 3" PVC pipes at different lengths like a pipe organ to spread the bandwidth if you want to snoop on sounds really far away.
 
KlausST said:
Hi,


It´s your project. So tell us in technical terms (not microphone related, not sound related) what you want to achieve.

In your first post you talk about a microphone array. How many? How are they physically arranged?
How do you "connect" them? With "connect" I mean the algorithm on the digital side.
What is your idea? You say you are a digital guy. If you want to write code ... you first need a strategy.

****
High quality microphone.
There are many qualities for a microphone, like: dynamic, bandwidth, frequency flatness, impulse reponse...

What we don´t know: how important is the "sound quality" really. Is it for high perfomance audio productions? Or just to clearly understand the spoken words?

*****

I like to contradict. I can´t imagine the goal is "to use high quality microphones".
I rather guess you want a high quality result (how ever you define your result) ... with rather cheap microphones, but with features that allow the high quality result.
I understand that using "high quality microphones" may exclude some problems ... but you buy this with a lot of money. And maybe there are much cheaper microphones giving the same result.
What I want to say: you need to focus on the result. You need to define the result .... and then .. with the next step .. you need to focus on how to achieve this result.

***
See it like this:
If you want to transport a parcel from A to B very fast. Then you may buy a Lambourghini, because it is fast. But what does the Labourghini help if the parcel is too big for the boot? Or there is water between A and B.

****
What is an array of microphones? 3 x 3 = 9? 10 x 10 = 100? 32 x 32 x 1024?

Klaus
Click to expand...
I vote for the 3D 32 x 32 x 1024 array. :)

But, seriously, I think the parabolic reflector is the way to go. Not sure why an array is needed.
 
If you have a flat Lambertian pattern LED to represent roughly a cardiod mic aimed like an LNB for a satellite then you can see how to block stray emitted light as you might want to block for detected sound and obtain the focused reflection at an angle with foam insulation and block stray near field waves.

Otherwise the electret mics will work if you do the same foam aperture to parabolic dish. (just not the same quality and BW) Then play/block the cloth/felt backing with something opens sound to block near field sound and capture only differential pressure on the front. This will then give it the strength of speaker phone 10 m away. Making a sealed cover with 2 mm hole in front will amplify the air velocity for greater sensitivity rather just wide open 8 ~ 10 mm.
 
Last edited:
Shotgun microphones are available commercially, designed to capture sound from distant subjects and reject ambient nearby noise. Appearance-wise they usually resemble ordinary 'cardioid' microphones with the help of modifications. Expect to pay more than ordinary mics cost.

Whatever you choose, a major consideration is to minimize wind noise against the mic. The parabolic reflector idea (mentioned in other replies above) seems like a good option.
 
Thanks everyone for sharing their knowledge with me.
Would you share some website or source of information regarding microphone, their circuit design, parameters, etc?

I am more digital guy and I need to read more about this topic for this project.
 

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