【 Weak current college 】 teaches you to recognize and use the phone 2002】the

<br> <br> The types of a, microphone: the microphone is different according to their structure, generally consists of moving coil, Crystal-and carbon-particle-, aluminum belt and capacitive, etc. several, one of the most commonly .used is the moving coil microphone and capacitive microphone, durable, inexpensive, delicate, price is high, but the response. <br> Moving coil microphone through diaphragm sensing acoustic air pressure changes, driven into a magnetic field coil cutting magnetic and acoustic pressure strength .changes the weak current signal. Usually dynamic microphone low noise, no need to feed the power, easy to use, stable and reliable performance. <br> Capacitor microphone is a capacitive sensor. The capacitance of the poles is separated by a narrow air gap ., air-gap formation-capacitor of media. Between the two poles of the capacitive coupled voltage, Acoustic Vibration-induced changes in capacitance circuit currents also produce changes, this signal amplifier output, you can get quality very good audio signal. In addition there .is a kind of Ambassador-level split capacitor microphone, the level of material microphone diaphragm membrane electrode, do not need to work with polarization voltage, simplified structure, so that the microphone is very compact and cheap, it also has the characteristics of the capacitor .microphone, is widely applied in various audio devices and pickup environment. Capacitor microphone's sensitivity is high, the frequency response is good, the sound quality is good. <br> 2. main technical characteristics of the microphone <br> 1, sensitivity: < .br> The frequency of the 1KHz, 0.1Pa provides sound pressure from microphone input on the front 0 spindle, microphone output open output voltage, 10mV/Pa. Sensitivity and output impedance. Sometimes expressed in decibels and require 10V/Pa to 0dB, microphone .output normally millivolt, therefore, the sensitivity of the decibel value is always negative. <br> 2, frequency response: microphone sensitivity 0 spindle on the frequency and nature of the change. Requires the appropriate frequency response range, and the range of characteristic curve .to smoothing to improve the sound quality and suppression of acoustic feedback. The same sound pressure, while the frequency of different sounds when imposed on the microphone sensitivity is not the same, frequency response usually pass frequency bands of the difference between the number of DB sensitivity .. Passband scope widens, the number of decibels less indicates that the receiver's frequency response characteristics for the better, which is a small microphone frequency distortion. <br> 3. directivity: <br> Microphone for different directions of sound sensitivity varies, this is .called the direction of the microphone. Direction and the higher the frequency the frequency, the stronger the directivity. In order to guarantee the quality, the requirements of the microphone in the frequency range should be more consistent direction. Directional microphones are facing the back 180 .0 direction and the direction of the sensitivity of the margin, the difference is greater than 15dB are called strong directional microphone. Product specifications on often gives the main direction of the polar coordinates of the frequency response curve pattern, the general types: single-direction .of "heart-shaped"; the two sides of the "font 8," and "non-directional; circular" and the single nature of the "hyper-heart-shaped." Microphone sensitivity of the microphone directionality is select one of the .important factors. A microphone is a one-directional, some are all-directional, some is somewhere between the two, its direction is heart-shaped. <br> All-directional microphones pick up sound from all directions of consistent performance. When the .speaker used to walking up and down the microphone more appropriate, but in the environmental noise conditions should not be used. <br> Heart-shaped point to microphone sensitivity in the horizontal direction is heart-shaped, positive sensitivity maximum back side slightly small. .The microphone in a variety of PA system has excellent performance. <br> Single directivity microphone is also known as hyper-cardioid directional microphone, it's directional microphone more sharply than the heart, face an extremely high sensitivity, the other direction sensitivity attenuation sharply, .especially suitable for high-noise environments. <br> 4, output impedance: <br> Leader from microphone view into the microphone at each end own impedance as output impedance. <br> Current common microphone has a high impedance and low impedance. High .impedance values of about 1000 ~ 20000 ohm, it touches directly and amplifier; surface low impedance-50 ~ 1000 ohms, through transformer matches before and amplifier. High output voltage resistance group is slightly higher, but the leader of the bypass capacitance effects larger, .high frequency, but also vulnerable to external electromagnetic interference, so that the microphone is too long, the leader in General to 10 to 20 meters. Low impedance output no this bug, so the noise level is low, the microphone can be corresponding lengthening lead ., amplifying equipment with low impedance microphone lead-up to 100 meters. If the distance is longer, it should be added to the front-stage amplifier. <br> Third, the skill of the handset <br> Public broadcasting systems typically use a .high reliability, low dynamic large heart-shaped pointer to type in the circle of the microphone. <br> The nature of the very high capacitance microphone sensitivity, the ability to reproduce sound and clear. The front of the reception of sound, the biggest .gain. You can filter from the surrounding noise, very suitable for background noise of the environment. We can understand the directivity microphone gain in all directions are different, the largest side of the front, rear and minimum. In the electrical specifications, we call .it high Fr ratio (FronttoRandomresponseindex). To enable the microphone of the best, you must first understand some microphone use skills. <br> 1, the speaker microphones is the best location for 15 ~ 40 cm. <br> If the distance is .too close to the speaker's bass section will vary depending on the volume too much distortion. If the distance is too close, will produce a "near-field effect" their performance is increased too much bass, speech vague, serious you couldn't understand .completely. But if the background noise is too large, sometimes had to speak near the MIC. You can choose to decay bass microphone, a better microphone design containing bass attenuation devices can reduce too close to the microphone of distortion. If you do not have .a microphone, amplifier, compression bass is also very helpful. <br> If the speaker must longer distances, the microphone will be included in other sound space, thus affecting speech clarity. If the microphone and speaker with a finger, the speakers are outgoing .voice would be a microphone income after and repeat the amplification, the situation is worse, last may be outAre howling. <br> 2. the microphone should be aligned with the mouth, to the line. <br> Due to the nature of the .microphone receives direction from the line of maximum sensitivity of the sound, so the speaker you speak is a good idea to make the microphone at the mouth, to the line to avoid sound variation. <br> 3, to maintain a certain volume. < .br> In the public broadcasting system, may also adopt volume limiter, to protect the amplifier. Volume limiter helps users control microphone output volume to avoid sudden volume control, frightened audience, or prejudicial to the sound device. <br> Volume limiter function not .in "introduction correction" speaker for Cadence, but rather help the speaker to clear and gentle tones, convey the message that you want to convey..