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
- 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
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:
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
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
Gently push them into place. Don't be too forceful, as you might snap the plastic.
Step 5: Insert microphones
Step 6: Drill LED holes
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
When you are done, solder one end of your 220 ohm resistor to any of the ground pins.
Step 8: Install stuff
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
Once done, build another.
Step 10: Wire and glue
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
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
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
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.