Sound Recording @ Zero Noise

Hi, this is an instructable which solves the problem of sound recording in general room environment. Have you ever faced trouble in recording videos/live lectures/conversations/television programs using a screen recorder and mic. generally we do face trouble with others speaking around the mic, vehicular noises, air buzzing and what not even the slightest of the slightest body tapping movements.

So, I have come up with an idea to solve this issue by using simple acoustics damping materials which we see around daily in our house. These materials don't even costs much and this project was build with not just more than INR 200₹ / USD 3$.

So lets start Building it........

Materials

1. 8 ohms small Speaker - 1 No.s

2. Mic - 1 No.s

3. Deo/Spray Caps (plastic) - 2 No.s

4. Aux Cable - 1 No.s

5. Surgical Cotton - 200 Gms

6. Sponge (Foam) - 30 * 25 * 20 Cms

7. Cardboard box - 25 * 20 * 10 Cms

Tools

1. Hawk saw Blade

2. Scissors

3. Cello Tape

4. Cutter

5. Fevicol (white glue)

6. Synthetic glue

7. Soldering Gun and Lead

8. Multimeter

9. Ruler

10. Tweezer

1. First take the Aux cable which is equipped with two sided 3.5mm jack pin. Cut the wire exactly in the middle length as shown in the picture.

2. Now take the two spray/deodorant bottle caps and make a small hole such that the aux cable can be inserted using the heated soldering rod.

3. Now insert the cables into each cap and solder the mic to one of the wires and a speaker to the other.

4. Each cable has three wires (a ground, right and left pins respectively), short the right and left pin wires and forming a two wired cable.

5. Now using the multimeter, Put it on the continuity setting and check now which terminal is which on a microphone. Place one multimeter probe on the outside metallic casing of the microphone. And place the other multimeter probe on one of the two terminals on the top of the microphone.

If the multimeter beeps, signaling continity, then the terminal you are on is the negative or ground terminal. If the multimeter doesn't beep, signaling discontinuity, then the terminal you are on is the positive terminal of the microphone.

6.Similarly in the three segments of the 3.5mm jack the last segment which is close to the wire end is the negative terminal. place one multimeter probe at the third segment of the pin and other at one end of a wire, the one that beeps is the negative wire.

7. A speaker usually can be wired irrespective of polarity. so solder two wires with the aux cable and test if everything is working fine.

Pre-Testing

1. Once the mic and speaker is soldered to aux cable, they are to be checked if they are properly functioning. To find out plug the mic cable into laptops mic (red) socket and go to Control Panal > click on Speech Recognition > Select Start Speech Recognition > Speak into the mic and see whether the level is fluctuating as you speak.

If every thing is fine, the mic is ready for the use.

2. Similarly plug in the speaker cable into the Speaker(black/green) port of the laptop and play a sound clip and if the sound emits from the speaker inserted then it should be working fine and pre-testing is done.

Capsule Enclosure

1. Once the testing is done, Insert some surgical cotton into the both the caps and secure the mic and speaker such that they both sit properly and glue it with fevicol.

2. Once they are glued allow them to rest and after setting, seal the mouths of both the caps using synthetic glue

(Note: See that there is a little gap in between the speaker and mic inside the sealed caps. They should not touch each other and a air gap is mandatory.)

3. Once the caps are sealed, Roll the Capsule in a thick sheet of Cotton bundle. here cotton acts as a Acoustic absorption material so that any kind of unwanted vibrations are absorbed inside and no buzz sound is created in the recording.

Inserting Capsule into Cardboard Box

1. Once the Capsule is ready then take the cardboard box and insert some cotton and then place the capsule and secure it in such a way that it doesn't moves when shaken. fill the gaps of the cardboard completely with cotton and punch two holes on to one side of the box and take out the aux cables from those holes.

2. Once this is done seal the whole box using a duct tape such that no air goes in or out.

Layering of Sponge sheets

1. Now take the Sponge cube and cut accordingly into 3 cms thick sheets.

2. Once the sheets of sponge are cut out using the hawk saw blade, stick each sheet using the glue on to each side of the card board box and completely cover it using the sponge sheets.

Here the sponge foam sheets act as Acoustic dampers, which obstructs external noises into entering into the cardboard box such that no noise is affecting the sound quality.

Once all the steps are done here is the final recording cube. For final Testing I have recorded a video in a much noisy environment and even in a home theater setup and the results are pretty good.

No noise/external sounds are heard in the recording...... Now that's how you can record any stuff using this small recording cube... Thank you !! Have fun !! Stay Creative !!