Applications, Feedback Prevention | Viking Electronics E111 manual

Applications

Feedback Prevention

When the overall gain of a sound system is increased, feedback will occur at frequencies where the system response has peaks. Suppose the system has an uneven frequency response like that shown in the following diagram. The frequency at which feedback will occur when gain is increased is about 500Hz. In this case, feedback may be prevented by attenuating levels at 500Hz by 5dB to 7dB with the E 111/112. If the overall gain is again gradually increased, feedback will occur next at about 125Hz. It may be stopped by attenuating the levels 2dB to 3dB at that frequency. In this procedure, sufficient gain in the sound system is obtained before feedback. When the equalizer is used for this purpose, the bandwidth controls are turned anticlockwise to prevent affecting other frequencies not needed for equalizing. In addition, the frequencies at which feedback will occur are not necessarily the same for each system and environment, therefore the equalizer is more effective if the center frequency control is made use of to precisely match center frequencies with the frequencies at which feedback occurs.

Room Equalization

In a sound reinforcement system for a room, the clarity of sound can be adversely affected by the room frequency response including standing waves (room resonances), reflections of sound, and relations between direct and indirect sound.

The E 111/112 are effective tools to equalize the room frequency response to a flat response and improve sound clarity.

The effective use of the equalizer sliders, center frequency controls, and bandwidth controls make it easy to equalize various frequency responses in rooms to be flat. For example, suppose that there is a room frequency response as shown below.

Sound LevelPressure

Frequency

The equalizer sliders, center frequency controls and bandwidth controls are set as shown below.

The response of those frequencies at which the corresponding equalizer sliders are set to 0dB positions will remain unchanged regardless of the positions of the center frequency controls and bandwidth controls. The overall response after equalization will then be as follows.

Sound Pressure Level

Before equalization	Frequency response	Frequency response
Before equalization	of equalizer	after equalization

Frequency

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E111 specifications

The Viking Electronics E111 is a versatile and reliable entry phone designed to enhance security and communication in various settings, including schools, businesses, and residential buildings. This product stands out for its robust construction and user-friendly features, catering to users seeking both durability and functionality.

One of the main features of the E111 is its high-quality communication capabilities. It is equipped with a built-in speaker and microphone, allowing for clear two-way audio communication between the entry point and the designated answering location. This is particularly beneficial in situations where immediate interaction is necessary, such as for visitor access or emergency notifications.

The E111 utilizes advanced technology to ensure reliability and ease of use. It incorporates a touch-tone keypad, making it easy for users to dial specific numbers without requiring extensive training. The keypad's design is user-friendly, featuring large buttons that are easy to see and press, even in low-light conditions.

Another notable characteristic of the Viking E111 is its robust construction. The unit is housed in a rugged, weather-resistant enclosure that can withstand harsh environmental conditions. This makes it suitable for outdoor installations where exposure to moisture and temperature fluctuations is a concern. The durable design ensures that the E111 will provide reliable service over time.

In terms of installation, the E111 is designed for straightforward integration into existing systems. It offers multiple mounting options, which can accommodate various installation preferences and locations. The unit can be connected to a standard telephone line or integrated into a larger intercom system, offering flexibility to suit the specific needs of any facility.

Moreover, the E111 features adjustable volume controls, allowing users to customize audio levels for optimal clarity. This adaptability is especially useful in environments with varying noise levels, ensuring effective communication regardless of surrounding distractions.

Overall, the Viking Electronics E111 entry phone is an ideal solution for enhancing security and communication at entry points. Its combination of advanced technology, user-friendly features, and robust construction makes it a popular choice for a variety of applications. Whether it is used in a commercial building, a school, or a residential setting, the E111 delivers reliable performance and ease of use for both residents and visitors alike.