Stereo Microphone




Introduction: Stereo Microphone

About: My name is Randy and I am a Community Manager in these here parts. In a previous life I had founded and run the Instructables Design Studio (RIP) @ Autodesk's Pier 9 Technology Center. I'm also the author of t…

It has come time for me to update my home recording studio to continue recording my own brand of intergalactic low-fi, disco, funk, folk rock. Rather than spend big bucks on a stereo mic setup that won't offer me the low quality sound that I am accustomed to, I have decided to build my own for next to nothing almost entirely out of found parts. Now I can get awesome panning effects that can easily be mimicked in software, but never truly replicated.

For those that don't know what a stereo mic is, it is basically using two microphones to record to both the left and right audio channels of a stereo music track to give that "3D" effect.

Step 1: Go Get Stuff

You will need:

- A flexible lamp arm
- 24" x 6" sheet of 1/8" acrylic
- 12" x 12" sheet of 1/8" milky white acrylic
- A laser cutter (or handsaw)
- A heat gun
- An oven mitt
- Table clamps
- An IKEA clock frame
- Two metal washers
- Two 1" (or larger) rubber grommets
- Two dynamic microphones
- A dozen LEDs
- Two BC546 transistor
- Two 100uF capacitors
- Two 2.2K resistors
- Two 47K resistors
- A 220 ohm resistor
- A 5V power transformer (give or take 1 volt)
- Red and black solid wire
- A panel mount stereo jack
- An SPST pull cord switch
- A power drill (with assorted bits)
- Assorted hand tools

Step 2: Cut Your Acrylic

Cut your acrylic using the following templates below.

One is for the bracket that holds the microphones, another other is a cover to make the base of the mic look all pretty-like and the last is a perf. board for building the circuit (print 2 or 3 of these using your extra scrap material after making the other cuts).

I laser cut them with a 75W laser with the following settings:
Speed: 12
Power: 100
Frequency: 5000

If you don't have a laser cutter, print out the template and tape or draw them onto your material. Proceed to cut them out with the tools you have.

Step 3: Clamp and Bend

Bolt your microphone bracket centered upon the flexible lamp arm.

Clamp the flexible rod to the table and slowly heat it with the heat gun until the sides start to flop.

The acrylic should be getting rather hot, so I recommend using an oven mitt.

Bend the acrylic into a U-shape until you are happy with the results. Let it cool to harden.

If you are unhappy with the final results, just re-heat it and try again.

Step 4: Insert Grommets

Carefully insert your rubber grommets into the holes on each side of the bracket.

Gently push them into place. Don't be too forceful, as you might snap the plastic.

Step 5: Insert Microphones

Place your microphones gently through the holes, angled towards each other, until they are held firmly in place.

Step 6: Drill LED Holes

Now we need to drill holes around the inner bottom of your clock for your LEDs.

I first lined this part with tape and marked it because I didn't want to put any extra markings on the case itself (in case I made a mistake).

I then drilled the holes.

Step 7: Wire LEDs

Insert your LEDs into the holes, pointed towards the inside of the case. Wire all of the longer power pins together and all of the shorter ground pins together.

When you are done, solder one end of your 220 ohm resistor to any of the ground pins.

Step 8: Install Stuff

Drill appropriate sized holes for your audio jack and pull cord switch and then insert them into the case.

Also, cut the end off of your 5V power transformer and pass that into the center of the case. This may require drilling an extra hole on the surface the LEDs are in (so the wire can be passed through). Once pass through, tie a simple overhand knot, so that it is held in place.

Step 9: Build Your Circuit

Build a circuit (as shown below) into your laser cut perf board.

Once done, build another.

Step 10: Wire and Glue

Following the schematic, wire and glue the two boards in the part of the clock frame where the clock mechanism used to be.

You should be able to wire up everything at this point, but the microphones themselves.

Remember not to cover the center hole, because you will be passing the rod through it in the next step.

Step 11: Clamp

Drill a hole in the center of the plastic clock face cover and insert backwards (face down) into the clock frame.

Slide the acrylic cover you made in stop two onto the rod.

Clamp the rod the clock base using washers and nuts

Step 12: Finish Wiring

There are two wire coming out of the microphone.

One is a ground wire and should be wired to ground. The other is the audio signal wire which should be wired to audio in on the preamp.

Wire a microphone to each of the pre amps.

Step 13: Record

Now you are ready to rock.

Have fun.

Some minor aesthetic improvements you may consider are:
1. Adding a weight to the inside of the base to make it a little less top-heavy.
2. Adding a felt circle to the bottom.

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    7 years ago

    "And that guys leg" - Rocket from GOTG


    11 years ago on Step 8

    Hi Randofo,
    I am also trying to make a desktop microphone(with my destroyed earphone which contains a mic.) at home with very simple steps can you help me to make it in a easy way plz help me ,mail me on

    I hate this new way to add comments, all the computers i have used it, have froze up, even on my quad core. Is there a way to change it back, BTW, Nice instructables.


    13 years ago on Introduction

    I dare you to (try) To say "Arduino Duemilanove" in it!(and upload the sound file)


    13 years ago on Introduction

    Good project! I know you wanted a lo-fi sound, BUT, to be fair, i must say that with this setup (wich resembles the ORTF quasi-coincident setup) you'll get a very unnatural phase distortion, even if the stereo image is a little wider. I would prefer a X-Y or coincident microphone technique. Easy to accomplish: just make sure the diafragms of the mikes are on the same vertical axis and 90 degrees apart.


    Reply 13 years ago on Introduction

    Ditto - this doesn't strictly look like real ORTF (but it's kinda similar) and coincident/xy generally gives better stereo results... I reckon this setup would work best with omni mics (unlike proper ORTF), but dynamic omnis are rare... Still I guess it's supposed to be lofi, so... :)


    13 years ago on Step 1

    That's alot of parts for a seemingly simple device. 0_o


    Reply 13 years ago on Introduction

    yeah. couldn't you just put two mics on a a special stand?


    Rockin' the Stereo Street Swag! 've been wanting to do a stereo recording i'ble...


    Reply 13 years ago on Introduction

    You should do one! Make us proud!


    13 years ago on Introduction

    It's funny, I just made one of these last week from 2 cardioid condenser mics, a piece of aluminum and an old tripod.

    According to this site (about halfway down the page)

    "The ORTF technique, which specifies two cardioid mics 110 degrees apart with 6.69 inches between the capsules, was designed to mimic human hearing."

    I set mine up the way they state and it works great. I have a Tascam US-122 USB sound card that has Phantom power on it hooked to an old laptop (Compaq presario, AMD K6), I use it for outdoor field recording (crickets, traffic, creek sounds, etc)


    13 years ago on Introduction

    This is very useful, thanks. I want to do one of these for me.