Almost all headsets that are designed to work with a PC have such “pathetic” characteristics that if you try to use a microphone from such a headset for sound recording or the same karaoke, you will get nothing but disappointment. There is only one reason for this - all such microphones are designed for speech transmission and have a very narrow frequency range. This not only reduces the cost of the design itself, but also contributes to speech intelligibility, which is the main requirement of the headset.
Attempts to connect a conventional dynamic or electret microphone usually end in failure - the level from such a microphone is clearly not enough to "build up" the sound card. Additionally, ignorance of the input circuit of sound cards affects and incorrect connection of a dynamic microphone ends the matter. Assemble a microphone amplifier and connect it “wisely”? It would be nice, but much easier to use the IEC-3 microphone, which was at one time widely used in wearable equipment and is still quite common today. But of course, you will have to connect “by mind”.
This electret microphone has sufficiently high characteristics (the frequency range, for example, lies in the range of 50 - 15,000 Hz) and, most importantly, it has a built-in source follower assembled on a field-effect transistor, which not only matches the high resistance of the microphone with the amplifier, but it also has more than enough output level for any sound card. The only drawback, perhaps, is that the microphone needs power. But its current consumption is so small that two AA batteries connected in series will last for many months of continuous operation. Let's take a look at the internal circuit of the microphone, which is located in an aluminum cup, and think about how to connect it to a computer:
The gray color indicates an aluminum cup, which is a screen and is connected to the common wire of the circuit. As I said, such a microphone requires external power, and minus 3-5 V must be applied to the resistor (red wire), and plus to the blue one. From white we will remove a useful signal.
Now let's take a look at the computer's microphone input circuit:
It turns out that the signal should be applied only to the very tip of the connector, marked green, and the sound card itself supplies +5 V to the red one through a resistor. This is done to power the headset pre-amps, if used. We will not use this voltage for two reasons: firstly, we need a different polarity, and if we simply “turn over” the wires, then the microphone will “receive” a lot. Secondly, the PC power supply is pulsed and the interference at these five volts will be decent. The use of galvanic cells in terms of interference is ideal - pure "permanence" without the slightest ripple. So, the complete scheme for connecting our microphone to a computer will look like this.
In this article I will tell you how to make a microphone, because a truly sensitive microphone can only be made with your own hands, more precisely, by remaking a standard microphone. Of course, many can argue with this statement, but not those who approached this issue seriously. Very often, people spend a huge amount of time setting up a microphone and finding the best combinations of a PC sound card and a microphone itself. In addition, if you have a laptop, then in most cases the sound systems in such computers also leave much to be desired. Well then, let's get down to business.
In the design of the microphone unit, we will use elements of electronics that have already served their time. Take an electret microphone from any old tape recorder or radio. If there are none at home, then a microphone from a mobile phone will do. You can even use two microphones at once, this will allow you to significantly expand the direction of the sound. The signal from the microphone or microphones must be amplified by a low-noise transistor of the VT1 type, then the signal will be fed to an operational amplifier of the DA1 type. The output of this amplifier can be connected both to ordinary headphones and further to processing or recording devices (for example, a laptop or a desktop computer). We will power the amplifier from the battery of an old mobile phone. They (mobile phone batteries) are good because the battery life of a microphone from such a battery will be tens of hours. And to charge the battery, use any USB port on your computer. Now about the amplifier. It is quite possible to leave it included in the port all the time, since the charging current in this case will be very small. The wire with the USB connector can be taken from the mouse. At the output of the amplifier, it is best to use a 3.5 mm jack - the same as for the headphones from the player. The volume control is also suitable from the headphones, and the rest of the details, for example, the SA1 power switch, must be made up of any small-sized ones.
Now we place the microphone components on a small board made of fiberglass. Next, glue a small piece of foam rubber onto the battery, and then lay the board on top. Now we tighten it all up with electrical tape and try on the regulator knob. After that, to eliminate interference and interference, we place our design in a tin screen, soldering it to a common wire. Please note that the microphone or microphones must be fixed in a piece of soft but dense material. Then we cut out a niche in a piece of foam rubber and insert the entire block into it, and from above we pull a fabric cover over it. By the way, foam rubber can also be used the one that is used for washing a car. Well, that's almost all - it remains only to make slots for the plug, as well as the volume control and switch. I note that such a microphone will be much better than any factory products, excluding, of course, professional equipment. But the fact is that for such equipment you will have to pay more than tens of thousands of rubles, and the cost of our product is a maximum of a thousand, given that we assembled it almost entirely from old parts. So, if you are not engaged in professional recording and you need a microphone for your personal purposes, then such a home-made design will come in handy.
Modern computer technology often has a lot of functionality and is equipped with the most stringent user requirements. But this is only in the situation when the PC user has acquired one of the latest models and enjoys all the “benefits of civilization”. But it happens when you just need to use a microphone to transmit information, but it is either broken, or it simply does not exist. In principle, this does not matter, because we know how to make a microphone out of headphones, and in this article we will also help you deal with an urgent problem quickly and easily. We will also talk about how to make a microphone from scratch.
In fact, you can buy such a device in advance if you plan to use a similar function when communicating via PC. The device is inexpensive. But if this is not your way, then we will now figure out how to make a microphone for a computer out of headphones. Moreover, this is a fairly simple process that does not take much time and effort! So, let's get down to business.
Instruction:
Important! If this device is missing, then you did something wrong, try reading this manual again, doing everything correctly.
Important! In order to check the performance of a microphone made from headphones, simply check the box where it says “Listen from this device”.
Important! Problems may occur during the connection and setup process. And so that you do not have to spend a lot of time looking for their solution, we suggest that you immediately read or save the information from our articles:
Today, electret microphones have almost completely replaced microphones of other designs. This indicates that with a relatively low price they have a flat frequency response, low weight and high reliability. If miniaturization is extremely necessary, then by this property they have no equal.
An electret microphone is a classic capacitor, one plate of which is made of a fairly thin layer of polyethylene film, located on top of the ring. The film is subjected to a process of bombardment with a beam of free electrons, which penetrate a short distance, due to which a space charge is released, which can be stored for a sufficiently long time. This type of dielectric is called an electret, and it is for this reason that the microphone is called “Electret”. A thin layer of metal is also applied to the film, which is used as one of the electrodes.
For work you will need:
Important! The larger the capsule diameter, the greater the bass range.
So, let's start the process of assembling a microphone for a PC with our own hands:
By and large, the microphone is already completely ready, but let's make another aesthetically important detail from foam rubber - a windproof cap:
Important! For this purpose, sections from used broken telescopic antennas, which you can sharpen with a scalpel, are excellent.
Whether you have high-end headphones or just can't find the right headset with mic that suits your tastes, is portable enough, and doesn't detract from your music quality, there's always a way. Turning your favorite headphones into a headset that can record voice, receive calls, and manage video chats is a real challenge.
Microphones and speakers are similar in many ways. Microphones convert sound into electrical signals, while speakers do the opposite by converting those electrical signals into sound. Despite this feedback to each other, they practically consist of the same components and work on the same sound principles.
Microphones and headphones are made up of vibrating diaphragms that convert sound into electrical signals and back to sound again, so you can use headphones to record sound.
When you speak into the microphone, the diaphragm vibrates, sending electrical signals down the wires inside the microphone and into the mixer's preamps. These electrical signals travel through wires to your amplifier and speakers, which have an electrical coil and magnet attached to the speaker cones. When the cones vibrate, these signals are converted back into sound.
Speakers can work like microphones by reversing the flow of electrical signals, with sound waves entering the speaker, causing a magnet attached to it to vibrate, and then sending an electrical signal through its wires. The sound quality of re-tuned headphones is worse than custom-made microphones, but they can be slightly improved by adjusting the audio settings on your computer.
Recommendations: How to properly set up the headphone microphone on a Windows computer 
How to disassemble the headphones: instructions with a step-by-step photo of repairing all elements of the headset 
, Self-made simple headphones and a headset with a microphone 
Locate the microphone or line-in audio input on your computer and plug your headphones into the jack.
Open the Sound Control Panel by going to the Start screen. On Windows 8 software it looks like this:
The audio device manager program in the search field may be called "Sound" or "Sound Device Control". Click one of these options in the results to open the sound control panel.
Click the "Record" tab and if you have multiple devices, then confirm the use of the selected headphones, set them as default and click the "OK" button.
Go to the "Record" tab in the sound control panel. Tap your earbuds continuously or just touch them, watching for the green bars to react, indicating that your device is making noise.
After confirming that your impromptu microphone is listed and working, select it and click the Set Default button. Click the "OK" button, now you are ready to use your headphones as a microphone.
1. Find an audio recorder app that allows you to adjust the audio sensitivity to match the sound on your device. Alternatively, use an external preamp or mixer to perform the matching. Many mobile devices have tight automatic volume control.
2. In order to convert headphones to a microphone on iOS and Android operating systems, you will need an adapter with microphone and headset jacks that splits the input into two signals: one for the microphone and one for the headphones. Connect the jack to the microphone input of the adapter and connect the adapter to your mixer or audio interface. Do a couple of test recordings and make adjustments for the best settings.
3. You have a tiny microphone that you can use at a concert or shoot a hidden video with it, because thanks to its small size, the process is easy to hide.
It happens that sometimes there is no audio input on Android. In this case, the solution to the problem may be available via Bluetooth, which is also a microphone. So plug it in and look for an app like Easy Voice Recorder that can record with Bluetooth.
For iPad users, you can try Recorder Plus HD for Bluetooth recording. The problem is that sometimes Bluetooth can interfere, but if this phone headset is all you have, then it's worth a try.
DIY microphone amplifiers.
Amplifier for computer microphone with phantom power.
I got myself on the computer such a program as Skype. But here's one bad luck: you need to keep the microphone near your mouth so that the interlocutor can hear you well. I decided that the sensitivity of the microphone was not enough. And I decided to make an amplifier amplifier.
An Internet search turned up dozens of amplifier circuits. But they all needed a separate power source. I wanted to make an amplifier without an additional source, powered by the sound card itself. That would not have to change batteries or pull additional wires.
Before you fight the enemy, you need to know him by sight. Therefore, I have accumulated information on the Internet about the microphone device: https://oldoctober.com/en/microphone. The article tells how to make a computer microphone with your own hands. At the same time, I borrowed the idea itself: there is no need to break the finished device for my experiments, if you can do it yourself. A brief retelling of the article boils down to the fact that a computer microphone is an electret capsule. An electret capsule is, from an electrical point of view, an open-source field-effect transistor. This transistor is powered from the sound card through a resistor, which is also a signal current-to-voltage converter. Two clarifications to the article. Firstly, there is no resistor in the drain circuit in the capsule, I saw it myself when I took it apart. Secondly, the connection of the resistor and capacitor is done in the cable, not in the sound card. That is, one output is used to power the microphone, and the second - to receive the signal. That is, it turns out something like this scheme
Here, the left side of the picture is an electret capsule (microphone), the right side is a computer sound card.
Many sources write that the microphone is powered by a voltage of 5V. This is not true. In my sound card, this voltage was 2.65V. When the microphone power output was shorted to ground, the current was about 1.5mA. That is, the resistor has a resistance of about 1.7 kOhm. It was from such a source that it was required to power the amplifier.
As a result of experiments with microcap, such a scheme was born.
The capsule is powered through resistors R1, R2. Capacitor C1 is used to prevent negative feedback at signal frequencies. The capsule is supplied with a supply voltage equal to the voltage drop across the p-n junction. The signal from the capsule is isolated on the resistor R1 and fed to the base of the transistor VT1 for amplification. The transistor is connected according to the scheme with a common emitter with a load on the resistors R2 and the resistor in the sound card. Negative DC feedback through R1, R2 provides a relatively constant current through the transistor.
The whole structure was assembled by surface mounting directly on the microphone capsule. Compared to a microphone without an amplifier, the signal increased by about 10 times (22dB).
The whole structure was wrapped first with paper for insulation, and then with foil for shielding. The foil has contact with the primer body.
Microphone amplifier with single-wire power supply.
A microphone with a preamp placed in the case requires power wires to be connected to the device (in addition to a shielded signal wire). From a constructive point of view, this is not very convenient. The number of connecting wires can be reduced by applying the supply voltage through the same wire that carries the signal, i.e. the center conductor of the cable. It is this method of power supply that is used in the amplifier brought to the attention of readers. Its schematic diagram is shown in the figure.
The amplifier is designed to operate from an electret microphone of any type (for example, MKE-3). Power is supplied to the microphone through resistor R1. The sound signal from the microphone is fed to the base of the transistor VT1 through the coupling capacitor C1. The required bias at the base of this transistor (about 0.5 V) is set by the voltage divider R2R3. The amplified audio frequency voltage is allocated to the load resistor R5 and then fed to the base of the transistor VT2, which is included in the composite emitter follower, assembled on transistors VT2 and VT3. The emitter of the latter is connected to the upper contact of the XP1 connector (amplifier output), to which the central conductor of the connecting shielded cable is connected, the braid of which is connected to a common wire. Note that the presence of an emitter follower at the output of the preamplifier significantly reduces the level of interference at the microphone input.
Two more parts are mounted near the input connector of the device to which the microphone is connected: a load resistor R6, through which power is supplied, and an isolation capacitor C3, which serves to separate the audio signal from the DC component of the supply voltage.
The circuitry solution used in this amplifier provides automatic installation and stabilization of its operation mode. Let's see how this happens. After the power is turned on, the voltage at the upper terminal of the XP1 connector rises to approximately 6 V. At the same time, the voltage at the base of the transistor VT1 reaches its opening threshold of 0.5 V and current begins to flow through the transistor. The voltage drop that occurs in this case across the resistor R5 causes the compound emitter follower transistor to open. As a result, the total current of the amplifier increases, and with it the voltage drop across the resistor R6 increases, after which the mode stabilizes.
Since the current gain of the composite emitter follower (it is equal to the product of the current gain of transistors VT2 and VT3) can reach several thousand, the stabilization of the mode is very tough. The amplifier as a whole works like a zener diode, fixing the output voltage at 6 V, regardless of the supply voltage. However, when using a power source with a different voltage, it is necessary to select the divider resistors R2R3 so that the voltage on the upper pin of the XP1 connector is equal to half the supply voltage. Curiously, the mode is practically impossible to change by adjusting the resistance of the load resistor R5. The voltage drop across it is always equal to the total opening voltage of the transistors of the composite emitter follower (about 1 V), and changes in its resistance only lead to a change in the current through the transistor VT1. The same applies to the resistor R6.
Even more interesting is the operation of the amplifier in AC amplification mode. The audio frequency voltage from the lower output of the resistor R5 is transmitted by an emitter follower with very little attenuation to the upper output - the output of the amplifier. In this case, the current through the resistor is constant and almost does not fluctuate with sound frequency. In other words, the only amplifying stage is loaded on the current generator, i.e. for very high resistance. The input impedance of the follower is also very high, and as a result the gain is very high. With a quiet conversation in front of a microphone, the amplitude of the output voltage can reach several volts. The R4C2 chain does not pass the variable component of the audio frequency signal to the power supply circuit of the microphone and voltage divider.
A single-stage amplifier is not at all prone to self-excitation, so the location of the parts on the board does not really matter, it is desirable to place the input and output at different ends of the board.
Establishment is reduced to the selection of divider resistors R2R3 until half the supply voltage is obtained at the output. It is also useful to choose the resistor R1, focusing on the best sound of the signal taken from the microphone. If the input impedance of the radio device with which this amplifier is used is less than 100 kOhm, the capacitance of the capacitor C3 should be increased accordingly.
Connecting a dynamic microphone to the microphone input of a computer sound card.
The microphone input of the sound card is intended for connecting an electret microphone. Pin assignment of the microphone input connector is shown in Fig. 1. The audio signal is input to the sound card through the TIP pin. The power of the electret microphone is supplied through the resistor R to the RING pin. The TIP and RING pins are connected together in the microphone cable.
Rice. one
Almost all $2-$4 multimedia microphones are suitable only for speech recognition, telephony, etc. Although these microphones usually have high sensitivity, they have a high level of non-linear distortion, insufficient overload capacity, and also a circular pattern ( that is, they perceive signals equally well from any direction). Therefore, to record vocals at home, it is necessary to use a highly directional dynamic microphone, which allows you to minimize extraneous noise from the system unit fan and other sources.
A dynamic microphone can be connected directly to the microphone input of a sound card. The signal wire of the microphone cable must be soldered to the TIP contact, the shield to the GND contact, and the RING contact must be left free. If the microphone has two signal contacts - HOT and COLD, then connect the HOT contact to the TIP contact, and connect the COLD contact to GND. Since the sensitivity of a dynamic microphone is low compared to an electret microphone, a sufficient recording level is obtained only when the microphone is located at a distance of 3-5 centimeters from the performer's lips. This is not always acceptable as some types of microphones will "spit" despite the built-in windscreen. Such microphones must be placed farther from the performer, and to obtain a sufficient recording level, use a preamplifier. The diagram of the simplest preamplifier powered by the microphone input connector is shown in Fig. 2.
Rice. 2
This circuit works decently for me with the following ratings: R1, R3 - 100 kOhm, R2 - 470 kOhm, C1, C2 - 47 microfarads, VT1 - kt3102am (can be replaced with kt368, kt312, kt315).
The circuit is based on a classic transistor cascade with a common emitter. The load of the cascade is the resistor R of the sound card (Fig. 1). The gain depends on the parameters of the transistor VT1, the value of the feedback resistor R2 and the value of the resistor R of the sound card. Capacitor C1 is required for DC decoupling. Resistor R1 is used to eliminate clicks when connecting a microphone "on the go", if desired, you can exclude it.
On closer examination, it turned out that there was a constant voltage of about 2 V on the TIP contact of the microphone input of my SB LIVE 5.1. It was not possible to investigate the reason, and whether this is typical only for my copy of the sound card or for everyone. But it is absolutely certain that the performance of the circuit practically does not change when elements C2, R3 are excluded.
The advantage of this scheme is its simplicity. The disadvantages include large non-linear distortion - about 1% (1 kHz) at 1 mV at the input. It is possible to reduce non-linear distortion to 0.1% using an additional 100 Ohm resistor connected between the emitter of the transistor VT1 and the GND bus, while the gain decreases from 40 dB to 30 dB. The changes are shown in Fig. 3.
Rice. 3
Higher performance can be obtained using an external self-powered microphone amplifier connected to the line-in of the sound card. For example - assembled according to the scheme with a symmetrical input.
DIY microphone amplifier.
Probably, for many of you, there was a need to record sound on a computer, for example, when dubbing videos or creating clips. The use of Chinese inexpensive consumer goods is absolutely undesirable, firstly, because of the rather low sensitivity, and secondly, the sound quality
it turns out *dirty*, sometimes even your own voice becomes unrecognizable.
High frequencies have a significant and unjustified blockage, and their durability leaves much to be desired.
A high-quality microphone, - alas, we can not afford it!
But, there is a way out! Many have old, still Soviet dynamic microphones, such as MD-52 or similar ones. And even in their absence, these specimens can be bought for * mere pennies *. Do not try to connect such microphones directly to the sound card directly - the AF voltage at the output is too low. Therefore, we use the simplest microphone amplifier, on the widespread K538UN3 chip, its cost is less than 50 rubles. But we used an old chip soldered from an ancient cassette recorder. Directly, the microcircuit itself is connected according to a typical, common switching scheme, with a maximum gain. The amplifier is powered directly from the computer, the supply voltage is 12 V, although the operability is maintained even at - 5V, in this case, power can be taken from the USB connector.
Microphone amplifier. Scheme.
Electrolytic capacitors - any, for a voltage of 16V. The value of the capacitance of capacitors can be changed within small limits. The device can be assembled using a simple, hinged installation.
No tuning, the amplifier does not require and does not need shielding design. But, the use of shielded cables is desirable and not too long. Tests of samples showed a relatively low level of self-noise, a fairly high sensitivity and a very decent sound quality, even on built-in computer sound cards, such as AC97. The dynamic range is about 40 dB. To record sound on a computer, we used the Sound Forge program.
Well, a few more schemes for articles in the appendage.
Pure sound to you!
