Choice of components
Since the goals of voice amplification are to (1) make everyone hear well and (2) maintain the natural voice of each speaker, it is important that you select the right components for your audio system. The saying "you get what you pay for" applies here. So-called “research parts” often don't contribute to your goals with the reliability and quality you need. It is a good idea to consult an experienced audio technician when purchasing an addressing system. This will help you get a good quality system with sufficient performance, but not too powerful or too expensive for your needs.
The first connection to your audio system is the microphone. Each type of microphone is designed for a specific application. There is no one best for all situations. To amplify speech, the dynamic microphone usually meets your needs. It has good fidelity, is robust, relatively trouble-free and inexpensive.
Then decide which type of mic model is best suited to your needs. Should I choose a one-sided device that picks up sound from all directions or a one-sided device? Figure-to-figure shooting models are also available.
A unidirectional microphone is also known as a cardiology microphone because it responds to sounds in a slightly heart-shaped pattern on the front of the device. Since the back of the cardioid microphone is relatively dead, its use often helps reduce acoustic feedback. This is the scream that occurs when the microphone picks up sound from the speakers. However, by choosing the renal unit, we are sacrificing some advantages. If the speaker is a bit "off the microphone", it may not work properly. The kidney unit is generally not as robust as other types of microphones.
There are several advantages to using a directional microphone. When the speakers cannot speak directly into a microphone, eg. For example, when walking through a group of people, the omnidirectional pattern is more convenient. This microphone is generally a cheaper and more rugged device. Hence, it will do a great job in many uses. However, these microphones are more likely to pick up unusual noises and add acoustic feedback, especially when two or more microphones are in use at the same time.
Some microphones tend to produce an unwanted pop sound when spoken directly over words with a loud "p" or "t". Usually a suitable windshield will correct this problem to prevent the speaker from entering the microphone.
Microphone impedance must also be taken into account. A microphone is said to have high or low impedance, which is a description of its electrical properties and is not necessarily related to its quality or sensitivity. High resistance microphones are often chosen economically. However, some inherent issues reflect the obvious quality of the system. For example, if the microphone cable is no longer than 15 meters (50 feet), a high impedance system is suitable. However, if the cable exceeds 50 feet, a low impedance system is recommended to minimize high frequency losses caused by cable capacitance. The low resistance system also helps prevent tinnitus and interference from nearby radio transmitters such as CB, police radio, etc. Low impedance microphones should be connected using low impedance microphone cables. To use them, amplifier adjustments may be required, eg. B. Add input transformers to receive the low impedance signal and adapt it to the amplifier. All professional audio installations use balanced, low impedance microphone circuits.
The second connection of the audio system is for the amplifier. You must select an amplifier with an individual input and volume control for each microphone to use. This means that each microphone can be adjusted independently.
For target groups up to 200, it is good to choose an amplifier with an output power of at least 30 watts. Larger rooms require a lot more energy. A semiconductor device is generally more reliable and quieter than a tube amplifier. Of course, we have to choose a device to use as an address amplifier.
Speakers are our last link in the reproduction of the spoken word. There are many types of creators. We can choose speakers for small auditoriums and place a unit on each side of the stage. They are especially useful for temporary installations. For permanent installations, a distributed system of ceiling speakers is generally very satisfactory. This system is especially recommended when the ceiling is relatively low as the entire audience can sit at approximately the same distance from a speaker. Ceiling speakers should be placed in staggered rows, placed approximately one and a half times from floor to ceiling. Speakers closest to the pedestal can be connected to reduce the force, which provides more volume for the entire system before acoustic feedback takes place.
When the speakers are connected to the amplifier, they must be electrically connected to the amplifier. This is achieved by selecting the appropriate impedance connection on the back of the amplifier that best matches the impedance of the speaker. Most modern amplifiers offer so-called "constant voltage systems" to accommodate several speakers. Often a 25 or 70 volt output is used on the back of the amplifier. A 100 volt system is popular in some countries. At the lowest voltage, you do not need to plug the speaker cables into the cord. The constant voltage system requires the installation of a small transformer in each speaker to match the system. You are now ready to use your sound system.
Good suggestion
A microphone should be placed approximately 15 cm from the speaker's mouth, taking into account the height and descent of the head. It should be close enough to ensure sufficient volume without traces of acoustic feedback, but not too close to make the speaker uncomfortable or cause sound attenuation with normal head movement. A microphone near the speaker is also exposed to annoying "pops" due to the explosive nature of the speaker's breath when speaking certain words.
Correct sound level and good quality are extremely important. The tone and volume controls on the amplifier should be adjusted to reproduce each speaker's voice in clear, understandable and natural tones so that everyone can listen comfortably and easily. If the volume is insufficient or the quality is low, some words will be forgotten, making it difficult for the listener to understand. After a while, mental fatigue may begin, as the natural tendency is to stop listening and continue trying to understand the message. On the other hand, an excessive noise becomes oppressive and disturbing, resulting in "listener fatigue". Even in this case, the listener "closes" the attention and is deprived of the message.
If a microphone is not used for several minutes, the volume should be lowered to avoid voice or background noise. Logically, a full-time sound system operator is helpful. If this operator is informed in advance about the audio requirements for each speaker, everyone will benefit from the program.
Should "roaming microphones" be used for public participation? It depends on the size of the audience, the acoustics of the auditorium and everyone's hearing ability. Of course, if each commenter is encouraged to speak loudly, it is best to waste time wearing travel microphones for public commentators.