Directional microphone with your own hands. Two ways to make a microphone from ordinary headphones What can you make a microphone from

I think not all owners of ordinary, budget (cheap) microphones for a computer or laptop are completely satisfied with the sound quality and volume. Usually in such microphones, on headphones, in the form of a lavalier or desktop type, they have the following device. There is a plastic microphone housing itself, inside of which there is an electret-type microphone capsule. Such electret capsules are called condenser microphones. The capsules are quite small in size, their quality (if it is relatively cheap) is very good. They have connection polarity (plus and minus). A two-wire, rather flexible wire is soldered to this capsule, which is connected to a 3.5-type plug with its other end.

This microphone can be modified to make it sound much louder and better. I propose a diagram containing only a few details. This is a simple microphone amplifier. Despite its simplicity, this circuit makes the sound of a microphone capsule really much better. Moreover, the amplifier is powered from the same wire that goes sound signal. Note for those who don't know! The microphone jack of a computer has three pins, one of which is the case, it is also a minus for the microphone, the second pin is a plus ( constant pressure there is about 2.5 V on it) and the third contact is a signal one. In the circuit, the signal and positive terminals are combined.

Now about the scheme itself microphone amplifier. After the microphone capsule itself, there is a capacitor C1, which filters high-frequency noise. The circuit will work fine without it, but it's still better to put it. Also, an electret-type microphone capsule (condenser, also called) needs phantom power. It is fed through resistors R1 and R3. Resistor R2 trimmer type, they can adjust the amount of amplification of the sound of the microphone. All resistors are 1 kilo ohm. Capacitor C2 has a capacity of 47 microfarads, its voltage can be any. Note that it has a plus and a minus.

A bipolar transistor of the KT3102 type is placed in the microphone amplifier circuit. This low power transistor has a fairly high gain. It has n-p-n conductivity. Instead, you can put any other one with similar characteristics, for example, the same KT315. Moreover, when choosing another transistor, it is the high gain factor that is important, and not its power. Well, do not confuse the type of conductivity (transistors pnp type not suitable for use in the circuit). It is this transistor that makes the amplification of the microphone sound. Its base receives a signal from a microphone capsule, and in the collector circuit we already have an increased amplitude of this signal.

The amplified signal is fed through the wire to a 3.5-type audio plug. As you can see in the diagram, you need to solder two contacts together, this is a plus and a signal one. It is also important that the wire from the microphone to the jack is shielded. As practice has shown, the difference between shielded and non-shielded wire is tangible. A wire without a screen is affected by various external electromagnetic pickups coming from the network, high-frequency devices, etc. Unfortunately, budget microphones initially have a wire without a screen. So, if possible, replace this wire with a shielded one, you will immediately feel a positive difference.

In addition to shielding the wire, you will also need to make a screen on the circuit itself. For example, after I soldered the circuit, which turned out to be quite small, place it inside a plastic syringe (for 2 cubes). On top of the syringe body, I wound several layers of ordinary foil, which I electrically connected to the minus of the microphone amplifier circuit. As a result, it turned out that the entire signal path from the microphone capsule itself to the plug is shielded. After checking, it turned out that with such shielding, external electromagnetic interference and various pickups practically reduced to zero.

Besides important point is the presence of the so-called wind protection. It's that little foam case that goes over the microphone. This cover greatly reduces the effect of sobs coming from the lips of the speaker into the microphone itself. That is, when we put the microphone head directly in front of us, then those air flows that have a deaf, sobbing character, after amplification, are not reproduced in the best way. acoustic system. Foam rubber largely weakens these unpleasant sounds. So the presence of this foam cover is a must.

And one more important point. This is a selection of microphone capsules. Let's say I had 20 of these capsules. Many of them looked almost the same. I decided to check them all the same, but is there a difference between them? I connected these microphone capsules one by one to this homemade amplifier. After that, the computer produced a sequential recording of the same sounds with each of the available capsules. As a result, despite the similarity (in appearance), their sound characteristics are very different. Of the 20 pieces, only 4 proved to be of the highest quality. They issued clear sound, there was good volume, a minimum of noise and interference, as well as a wide range of reproducible frequencies. So not all mic capsules are the same!

Video on this topic:

P.S. If, before soldering this circuit of a simple microphone amplifier, I was suspicious of the final result (the circuit was too simple). Then after I soldered it, picked up the best microphone capsule, put shielding on the wire and the microphone amplifier case itself, I was convinced of good quality this scheme. The sound that can be obtained using a regular budget microphone and after soldering the amplifier with its improvements was very different. This simple microphone amplifier makes the sound much better, louder, clearer. So I advise you to collect it for your needs.

It’s very difficult to do without a computer microphone now, you can’t use it without it. voice search, you will not be able to chat with a friend via video call. However, not all computers have built-in microphones, moreover, they often do not have very good sensitivity. You can solve this problem quite simply - assemble the microphone yourself.

Scheme

Circuit Assembly

(downloads: 206)

Microphone Assembly

I have already described one design of a microphone designed for the DPC, but its operation revealed a number of shortcomings, which are described below. So I tried to make a better model.

The result is two different microphones, one mono and the other stereo.

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Prologue.

My first homemade microphone had a too uneven frequency response due to the resonance that occurs in the tube. In addition, it allowed recording only monophonic sound. It was decided to build a more perfect model of the microphone, but, as always, do without turning and milling.

In the course of reflection, several ideas came up for making a slot microphone tube without the use of machines, and even the tube itself.

Washer slit microphone tube.

The slot microphone tube can be made from large diameter washers. If two holes are drilled in each washer, then you can use two pins to assemble a multilayer sandwich, and adjust the size of the slots with small washers.

This idea, in my opinion, has only one significant drawback. In order to drill holes in each washer with sufficient accuracy, a small jig would have to be made.

Tube slot microphone from transistor clamps.

If instead of washers you use clamps from old-type transistors, then you won’t have to drill anything at all. It remains only to collect the tube.

The disadvantage of a pipe assembled from standard clamps from transistors of the type P213 ... P217 is a lot of weight. If you use duralumin clamps from transistors of the KT801 type, you can get a fairly light tube. True, it will be difficult to place two microphone capsules in such a tube at once, so for a stereo wet phone you will have to look for another solution.

Slit microphone tube made of metal tape.

The slit microphone tube can be made from a narrow metal tape by rolling it into a helix on a template of the desired diameter. Then the width of the slots can be adjusted by changing the pitch of the screw.

Based on these ideas, I made two microphones - monophonic and stereophonic.

This time I omitted some details regarding the assembly of microphones and the manufacture of parts, since I have already covered them in detail.

Slit microphone from clamps from transistors.

This is a drawing according to which a slit microphone was made from transistor clamps.

1. Collar from transistors - duralumin.
2. Nut - steel, M2.
3. Grover washer - steel, M2.
4. Hairpin - steel, M2.
5. Gasket - cambric.
6. Shielded cable - Ø2mm.
7. Bushing - rubber Ø11mm.
8. Body - medical syringe - 5g.
9. The back wall is a medical syringe - 5g.

It turned out to be easy to assemble a microphone from clamps from transistors. Here's what was used for the build.

1. Grover washer - steel, M2.
2. Shielded cable with 3.5mm Jack connector.
3. Helical spiral - solder Ø2mm.
4. Velvet.
5. Electret microphone capsule - Ø10x7mm.
6. Clamp from transistors such as KT801, KT602, KT604.
7. Medical syringe - 5 gr.
8. Stud, nut - steel, M2 (studs were made from a bicycle spoke).

To do appearance more presentable, I wrapped the body of the microphone, made from a syringe, with heat shrink tubing. First I seated the front part, and at the end of the assembly I inserted the cover and seated the tail part.

Here's what happened.

Directional slit stereo microphone made of metal tape.

This is a drawing from which a directional stereo microphone was made from a metal tape.

1. Screw - M1.6x5.
2. Nut - M1.6.
3. Collar - steel, S0.3mm. (tin from a tin can).
4. Tape - steel, S0.5x8x50mm.
5. Screw - M1.6x5.
6. Partition - medical syringe 20gr.
7. Bushing through passage - rubber Ø11mm.
8. Cargo - solder Ø2mm.
9. Krpus - medical syringe 20gr.

Very few parts were needed for this microphone.

1. Shielded mono cable - Ø2mm.
2. Shielded stereo cable - Ø3mm.
3. Screw - M1.6x5.
4. Bushing through passage - rubber Ø11mm.
5. Collar - steel, S0.3mm. (from a can).
6. Screw, nut, washer - M1.6.
7. Cargo - solder Ø2mm.
8. Electret microphone capsule - Ø6x6mm.
9. Syringe medical 20gr.
10. Tape - steel, S0.5x8x50mm.
11. Heat shrink tube – Ø8mm.

In order not to deal with painting, I covered the steel tape with heat shrink tubing, and then rolled it into a helical spiral pos. 1 on the body of a 10 gram syringe.

From the body of a 20-gram syringe, I made the microphone body pos.3, and the baffle pos.2 from the piston of the same syringe.

At this stage, you can drill three holes for attaching the tube to the body and cut the threads.

To reduce the length of the unshielded wires going to the microphone capsules, I extended the stereo cord with two small pieces of mono cord. The picture shows how it was done. Thick paper is used as insulation.

The microphone housing, as in the previous design, was covered with heat shrink tubing.

Another picture explaining the assembly order.

Here's what happened.

And here's how it works.

Small details.

When testing the first pair of microphone capsules, it turned out that their frequency response differed too much. In anticipation of the market day, I even assembled a small stand to test microphones without using soldering. I bought a few more capsules for $ 0.4, so that I had plenty to choose from. But, the very first pair taken from this purchase turned out to be consistent in frequency response. I didn't experiment anymore.

A microphone is an electro-acoustic device that converts sound vibrations into electricity. The microphone is the primary device in the audio path chain. The generalized principle of operation of a microphone is that the pressure of sound vibrations acts on a thin membrane of a microphone device. Then, the vibrations of the membrane generate electrical vibrations. Depending on the type of microphone, the physical phenomena of electromagnetic induction, capacitance change or the piezoelectric effect are used for these purposes.
Microphones are used in many audio devices such as mobile phones and various audio equipment, for radio communication, and they are also primary sensors for ultrasonic testing devices.

Today, electret microphones have almost completely replaced microphones of other designs. This suggests that at a relatively low price, they have a flat frequency response, low weight and high reliability. If miniaturization is necessary, then by this property they have no equal.

1 - Insulator; 2 - Metal ring, but which is stretched with a film; 3 - Base, it is also one of the microphone plates; 4 - Film, it is another microphone plate; 5 - Microphone outputs.

An electret microphone is a classic capacitor, one of the plates of which is made of a fairly thin polyethylene film, which is stretched over the ring. The film is bombarded with a beam of free electrons penetrating the short distance, which generates a space charge that can persist for quite a long time. This type of dielectric is called electret, therefore the microphone is called - "Electret". A thin metal layer is also applied to the film, which is used as one of the electrodes. The other is a metal cylinder, the flat surface of which lies at a small distance from the film.

The vibrations of the film, from the acoustic waves, generate an electrical current between the two electrodes. Since the value of this current is extremely low, and the output resistance reaches gigaohms, it is extremely difficult to transmit the received useful signal through the wires without noticeable distortion. Therefore, to match the huge resistance of a microphone with a low input impedance, a matching stage is used, built on a field-effect transistor, which is structurally manufactured in the case of a typical microphone capsule.

Mic - electret microphone; VT1– field-effect transistor; R1 is the load of the matching stage; R2 - microphone supply ballast resistor; C1 - separating container.

The body of the MK capsule is usually made of metal, which shields the microphone and matching stage from various external electric fields. A capsule is a device in the case of which there is not only the MK itself, but also a matching cascade on a unipolar transistor. As can be clearly seen from the diagram above, an external power supply is required to power the matching stage. This voltage is supplied to the input of the microphone amplifier directly from the amplifier circuit.

First, we need an electret microphone capsule, in principle, it is easy to get it from an old Chinese radio or an outdated landline phone. The larger the capsule diameter, the greater the range low frequencies, a piece of flexible thin wire, a standard 3.5mm jack plug, a plastic case from a syringe, a small paper clip and a piece of foam rubber

So, let's start assembling: We cut off a small body of the syringe, from the side where the needle is attached, approximately one gram near the pointer using a clerical knife. We remove already unnecessary markings from the syringe body with acetone or another solvent. We process the cut edge with fine sandpaper.

We put a shielded flexible wire into the hole and make a small knot. Then we solder the capsule so that the braid of the shielded cable is connected to the metal case. We insert the capsule into the case and snap the place where the needle was inserted with the foot of a standard clerical clip. On the other side of the flexible shielded wire, solder a 3.5mm Jack plug, and the left and right channels are connected together.

In principle, the microphone is already ready, but we will make another important aesthetic detail from foam rubber - a windproof cap. To do this, cut off a square piece of foam rubber with a knife.

We make an even cylindrical recess with any sharply sharpened tube; for these purposes, sections from old broken telescopic antennas are perfect, which can be sharpened with a scalpel by rotating the tip along the inner surface of the tube. We cut off everything superfluous and strive to get something similar to a sphere. Here, such a cute microphone turned out to be the output of our imagination.

A microphone is a device that converts sound vibrations into electrical current. In sound transmission, the microphone is the primary link in sound reception. A microphone is a useful device that can be used to communicate on the Internet, as well as to record voice or sounds (instruments, special effects). However, high-quality microphones cost a lot of money, and cheap ones will not be able to provide sufficient sensitivity and quality.

In this article, we will tell you how to make a microphone suitable for daily use with your own hands.

What can you use a homemade microphone for?

Of course, making a condenser microphone for vocals or podcasts with your own hands is almost impossible - their device is too complicated, which can become a hindrance for a person who is poorly versed in electronics.

Electret microphones are much simpler in design and therefore more reliable. In addition, small size and low cost electret microphones allow you to use them almost anywhere where sound reception may be required.

Here is an easy way to make such a microphone with your own hands.

What will be needed?

• Electret capsule - you can pull it out of the old cell phone or radio tape recorders;
• Jack 3.5 plug for connecting a microphone to a computer;
• Microphone body - a cylinder from a syringe is well suited;
• Paper clip - for fixing the case and further attaching the microphone, for example, to clothing;
• Thin wire - cut off a small section 1-1.5 meters long;
• Black foam - a small piece to protect from the wind.

Manufacturing procedure

To make it easier for you to navigate, look on the Internet for photos of a homemade microphone or a standard electret microphone (“labeled”).

• To make a microphone body - you need to cut off the tip from the syringe body with a knife. You can erase the divisions on the syringe with a solvent;
• Insert a wire through the cone of the syringe and tie a knot at its end to secure the microphone in the body;
• Solder the electret capsule to the wire from the node side - connect the shielded braid to its body;
• Install the primer in the body, and fix the cone with the eye of a clerical clip;
• Solder the second end of the wire with the plug, additionally connecting the left and right channels together;
• In a piece of foam rubber, make a narrow round hole for the microphone. With a knife, you can cut off extra corners - this way you get a decent windproof cap.

That's it, your homemade microphone is ready! You managed to create a sensitive measuring microphone with your own hands, which is also well suited for communication.

DIY microphone stand

As a rule, expensive and high-quality microphones are bought for serious work or hobbies, whether it is professional sound recording, broadcasting or vocals.

In the vast majority of cases, for comfortable work and for the closest access to the sound source, you have to additionally purchase a special stand for such microphones. Now we will tell you how to make a desktop microphone stand at home.

What will be needed?

Lamp on the clamp - can be purchased at any electronics store. Attention: the mass of the lamp must correspond to the mass of your microphone, in otherwise a microphone on a weak clamp will easily fall under its own weight.

The holder depends on the type of your microphone: for a dynamic microphone, a holder can be purchased at a price of 250 rubles, for a condenser (spider type) - at a price of 500 rubles.

It is possible to find and purchase an adapter for a microphone holder for easy installation on a clamp.

Manufacturing procedure

• Cut and pull out the lamp wire;
• Disassemble and remove the lamp cover;
• Attach the microphone mount to the thread to the pantograph of the lamp - due to a mismatch in the thread, you can only screw the microphone mount once;
• Attach the microphone holder to the mount;
• Install the microphone itself in the holder, fix the stand to the table.

Ready! Now you have a convenient adjustable microphone stand that can be easily attached to the table, and the clamp design allows you to screw a pop filter and other accessories to it.

DIY microphone photo