Most often, do-it-yourselfers who make a measuring microphone are the ones who need to not only check, but also adjust the amplitude-frequency characteristics of a living room, studio, concert hall or any other premises. In such a situation, the product is used in combination with a test signal generator and a powerful spectrum analyzer. It is worth noting that the last unit can be presented as a separate hardware device. Some craftsmen learned to replace it with computer programs. Recently, high-quality monitor processors have gained immense popularity. These are advanced hardware and software solutions. They may include measuring microphones, test signal generators, and software. Due to this, you can adjust the amplitude-frequency characteristics.
Before you begin making a measuring microphone with your own hands, you need to study which particular parameters are basic in the unit. Experts note the following characteristics:
- The principle of operation and purpose. A ready-made microphone can be used in various industries, which is why certain requirements are imposed on the unit. In each case, there are positive and negative characteristics that the user can adapt to their needs.
- General orientation. This is a peculiar ability of the device to respond to even the smallest changes in sound pressure relative to the direction of the sound. The final parameter depends on the design of the capsule, which is the basis of the entire product.
- Sensitivity. This ability characterizes the overall efficiency of the product to convert incoming sound pressure pulses into current. Due to this, the specialist can understand exactly what voltage will be at the output of the unit at a certain sound pressure. The higher the sensitivity, the higher the resulting results will be.
Every beginner who decides to build a measuring microphone with his own hands, should know that this device converts changes in sound pressure into electric current. For work, you can use the simplest scheme.
This parameter displays the sensitivity of the product to the main sound location. Today, every master can build a measuring microphone with his own hands, which will suit a certain orientation:
- Supercardioid. The sound is perceived quite narrowly, the noise that comes from the back of the unit is partially captured.
- Cardioid. The microphone perceives only those sounds that go in front. Hypercardioid. The "back" zone prevails over all the others.
- Eight. The product equally well perceives the sound coming from the front and back.
A home-made measuring microphone can be omnidirectional. Such products perfectly perceive sound from any point. Advanced models can be equipped with a universal switch that allows you to adjust the necessary parameters.
Some microphones may be classified as phantom », When the necessary current flows through the cable that connects the unit itself to the receiving unit. This option eliminates the need for the user to independently control the battery level. Freedom of movement directly depends on the length of the network cable. Products with a high-quality battery are in the greatest demand. But you need to remember about regular recharging. The master can make a measuring microphone for frequency response analysis, which will work directly from two power sources. This is the most profitable and versatile solution.
The measuring microphones differ in their sensitivity level. It can be measured in decibels as well as millivolts per pascal. The master must take into account the nominal resistance of the unit to alternating current. It is on this parameter that the compatibility of the microphone with the existing equipment to which it is connected depends. Impedance is especially important in a professional environment. If the product is paired with a smartphone, computer or laptop, then the rated voltage is not so important parameter.
If you prepare all the necessary tools and materials in advance, then at home you can build a home-made measuring microphone from WM60. In order to prevent the most common mistakes, you need to familiarize yourself with the elementary scheme in advance. Voltage is supplied to the capsule through a powerful 15k resistor. In parallel, a ceramic capacitor is included in the unit, which independently eliminates high-frequency noise and interference. After that, the signal goes to the first stage of the amplifier.
The main steps
As a solid base you can use a metal chrome tube, as well as the housing from the old probe or sensor. The classic version consists of 2 base parts. The first is a rugged chrome tube microphone housing. An electret capsule and a printed circuit board are required to be installed in the internal compartment, on which the components of the first stage of the amplifier and the voltage stabilizer are pre-wired. The second part is represented by a small box with an XLR connector, a printed circuit board with matching stages. You always need to remember that all the details are designed for specific cases, because of which some mechanisms may simply not work. Going through the methods of installing a measuring microphone, you need to remember that the power will be supplied via XLR from a phantom source of 48 V.
The measuring microphone can be equipped with a receiver that perfectly combines with various audio equipment. Many craftsmen prefer to use the transmitter, which is ideal for compact units with wireless power. This is a great option for professionals, as many working nuances are greatly simplified. You can also mount a stand or tripod mount. This approach will appeal to those who work in the instrumental and vocal industry. The product is also useful in concert activities.
The presence of a flexible leg allows you to freely change the position of the main capsule without first moving the microphone itself. For these purposes, a rigid foot with universal swivel mount can also be used. The user can connect a microphone to his computer to conduct conferences over the Internet. The radiation pattern can be controlled by switching the beam pattern. In professional products, this function is actively used to switch between different fronts of work. If the master has sufficient skills, then he can also build a headphone output, making the product universal. This option is typical for studio equipment, as it allows you to control the quality of vocal recordings. It is worth noting that headphones are most often connected via mini-Jack. If you need to reduce the signal level at the output, then you just can not do without an attenuator. Specialists use this device to attenuate the sound volume qualitatively so as not to overload the equipment.