How Can I Connect and Use Multiple Microphones for Real-Time Signal Processing?

[mike1111]

Hi,

I need to get 3 mircophone input into my computer so I can do some signal processing (using matlab) as close to real-tme as possible. I was wondering if anyone had any idea how to do this.

I was thinking of using usb mircophones but I don't know how to get it to read 3 microphone inputs and keep the signals separated.

Note: was also thinking of using a microcontrolled with analog microphone and ADC instead of going directly to the usb ports.

Thanks for any advice or ideas you can give.

 

[vk6kro]

You would probably need multiple sound cards. I've never heard of this, but this article says Windows supports it:
http://www.dxlabsuite.com/winwarbler/Help/ConfiguringMultipleSoundcards.htm

Maybe you could try one extra sound card for a start and see if it crashes Windows.

I've done this when a motherboard had a faulty sound card onboard, but you always disable the faulty one before you install the new one in a slot. Never tried two at once.

Normally, one sound card just combines all the inputs to give a single output for the computer. So this wouldn't be any good for you if you want to keep them separate.

Your multiple USB microphone idea sounds good. Depends if the software supports it and keeps the inputs separate.

I wondered too if you could have 2 microphones as mono signals on a stereo pair.
So, you could amplify the two microphone outputs to line input level and feed both of them to a stereo line input plug. (The mic input isn't usually stereo, it uses a stereo plug for power to electret microphones). Still only two microphones, but better than one.

 

[minger]

Rather than getting three sound cards, perhaps you can just get one sound card and an external preamp, designed for computer interface.
http://pro-audio.musiciansfriend.com/computers-peripherals/audio-interfaces

If you do go with way, stay away from M-Audio, I've had nothing but bad luck with them.

 

[vk6kro]

Not sure how that would help. Please explain.

He wants to get 3 microphone signals into the computer but keep them apart so that software can see them separately. Sound cards give one signal to the computer, we need 3.

Let us know if you find any way of doing that...

 

[DavidSnider]

Not sure how that would help. Please explain.

He wants to get 3 microphone signals into the computer but keep them apart so that software can see them separately. Sound cards give one signal to the computer, we need 3.

Let us know if you find any way of doing that...

He's suggesting to get a digital multitrack recorder that hooks into your PC. The sound card is only for output, the recorder takes multiple inputs. (Most multitrack recorders have their own line out built in too, so you may not even need that).

 

[minger]

Right, they're basically a recording interface. I have an old one that uses a serial port. The actual hardware allows for 4 inputs to be recorded simultaneously.

So, assuming that you have the software to capture it, its something that could be done for under a couple hundred bucks, plus cost of mics.

 

[vk6kro]

But, it still doesn't bring 3 inputs into the computer at the same time without combining them first.
He says "as close to real-tme as possible".

I'd try an extra sound card but I don't have any spare PCI sound cards.

Sound cards don't have to be expensive, but it would be good to know if the computer allowed multiple sound cards.
http://www.dealextreme.com/details.dx/sku.4666

There are also gadgets like these:
http://www.dealextreme.com/search.dx/search.sound card
The USB sound cards at the top look promising. Cheap enough too. (That price includes shipping).

 

[chroot]

USB microphones would be your best bet. You can probably use MATLAB's Data Acquisition Toolbox to read them independently.

- Warren

 

[mike1111]

Thanks a lot for the help and ideas, it be a while before I can get the equipment to test them.