Picture of Make a stereo microphone for $15
How to make a decent sounding stereo microphone for $15. This is useful for recording ambient sound, or using with a video camera that has a microphone input.

Example of the sound quality you can get out of this:
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Step 1: What you'll need

Picture of What you'll need
1 Female RCA to Male 3.5mm Cable:

2 Male RCA to Female 3.5mm Adapters:

2 3.5mm Microphones:

As user Rogue Agent pointed out in the comments, you should take a look at the frequency range of the microphones you're buying. The ones I linked to are made for voice recording, so they aren't the best for recording music/sound. Human hearing range is about 20Hz - 20kHz, so microphones closer to that range would work better.

Step 2: Put it together

Picture of Put it together
There really is no wrong way to do this.

Protip: Use the picture as a guide.

Step 3: You're done. Now put it to use

Picture of You're done. Now put it to use
Well, this instructable went by pretty fast. Probably because the whole "assemble it" part was incredibly simple.

Anyway, enjoy your new stereo microphone. Use it in place of your camera's horrible sounding built in one, or to record ambient sounds. Did I say that already? Oh, whatever.
gwynnebaer2 years ago
Could you save a step and parts by using a Female 3.5mm cable and skip the RCA->3.5mm conversion?
Snaffle J. Bean (author)  gwynnebaer2 years ago
It's possible. The problem with 3.5mm splitters is that there are two kinds: ones that split a stereo signal into two stereo signals, and ones that split a stereo signal into the left and right channels. The former are the most common, while the latter are a bit hard to find. The reason I used an RCA to 3.5mm converter was because that kind of cable is definitely one that splits a stereo signal into the left and right channels.

As long as you find a 3.5mm splitter that states it splits a stereo signal into the left and right channels, it will work the same as the one I built.
Since the sound is incoming rather than out, would that matter?
Snaffle J. Bean (author)  bobosos112 years ago
Yes. It would record stereo, but both the channels would be the same. Since it's splitting it into two female stereo plugs from one male plug, they would both get combined on the way to the male plug.

If you want to use a 3.5mm splitter, this might work
From the reviews, that looks like it would split into the two separate channels.
Rogue Agent2 years ago
Great, project! One thing to be aware of is that people will want to look at the frequency range on the mics they end up using depending on the intended application. The ones on the link are probably not an ideal range for music (100Hz - 5kHz), but would be fine for voice only. Human hearing range is about 20Hz - 20kHz. Many good sounding (but low cost headphones) reproduce 10Hz - 22kHz. The great thing about it is that it is modular, and with no soldering you could upgrade mics at any time.

Hey Rogue, what type of microphones would you use to capture acoustic instruments and guitar amplifiers. I want to record the ambiance of areas as well as the music I play in these areas.

Snaffle J. Bean (author)  Rogue Agent2 years ago
I'll add that in; Thanks.
Krayzi992 years ago
I didn't know there was such a thing!!! love it!!! although, there are probably easier methods... or, in my case, more lowcost, considering i dont have any mics laying around.
Snaffle J. Bean (author)  Krayzi992 years ago
Yeah. I think the cheapest you could go would be to buy two condenser microphone elements and one 3.5mm stereo cable and just solder each microphone element to each channel wire in the cable. That would only bring the price down to about $10 and would take more work, though.
Yeah, whether it save money or not, i love to solder
elangovan2 years ago
what is this ..................................
Great stuff!
Here's another solution. I used a 3.5 splitter from belkin,

I haven't a clue about electronics and expected it to work with two, mono, telephone mics.

I had to cut the ends from the splitter and fiddle with the connections till I got a proper stereo signal. I then hot glued it into a right frankenstein's monster but it works!
The disadvantage is the cost. £25. The advantage is a proper set of binaural mics which normally cost a fortune. Sorry no photo but here's the juice

(If you cup your hands behind your ears with binaurals, you can actually hear the difference in the recording)

P.S. I faded the piece for free with Audacity -
Snaffle J. Bean (author)  andragairdna2 years ago
Nice. I tried to do what you described, but the inner cables for the stereo splitter I used had some sort of colored coating on the wires that I couldn't remove. Did you have to deal with that?
Fred_T2 years ago
Hi, sound quality is amazing! Do you think any "cheap" (more or less 10$) microphone would be similar in quality?
Snaffle J. Bean (author)  Fred_T2 years ago
Mine were about $2.50 each, so it's possible. Just read the reviews on them to make sure; I skipped over 3 other microphones in that price range before I found the ones I ended up ordering because of bad reviews.
dasirrine2 years ago
The dog barking part of the demo video was good enough to make my cat freak out and run! :-)
grundisimo2 years ago
rimar20002 years ago
Very good idea!