Mode 2…Priority Pre-select switches (1-4) Down

In this mode, only one mic at a time can be “on.” The lockout bus shuts down all other mics until the first speaker pauses. As soon as the controlling microphone goes silent, the lockout bus goes inactive and any other mic can come on. This switching takes place without any syllable-grabbing delay, or pops or clicks. (This mode is known as “First-come-first-served” or “Filibuster.”)

This mode is very useful when the gain setting of the overall sound system must be close to the threshold of feedback, and additional microphones coming on could throw the system into feedback. The SmartMixer will not allow multiple microphones to be on at the same time in this mode. The switching is so fast and silent that the meeting can still be completely interactive.

Mode 3…One Priority Pre-select switch Up

The selected priority microphone can come on at any time and can override any other mic that is on (popularly called “The Chairperson” mode).

(Note that there may be special circumstances where two or three mics could be set to priority, so those speakers could talk whenever desired, but still override one or two non-priority mics.)

If multiple SmartMixers are used with AT8325/1.0 Link Cables, Priority Pre-select switches on all channels in use will have the control effects described above.

NOMA

The NOMA is factory set in the “off ” position. To turn on the NOMA function, unplug the unit, remove the top cover and change the setting of the switch designated on the circuit board by “SW25” (Figs. 4 and 5, page 11).

NOMA serves to maintain overall system gain by proportionately reducing amplifier gain as the number of open microphones increases. In a sound reinforcement system, this can tend to preserve the feedback margin and system stability. However, this action necessarily reduces the sound level of each individual person speaking, which may not be desired. In the end, use of NOMA often comes down to the preferences of the system’s designer and/or operator.

Generally speaking, use of NOMA is not desirable in applications such as teleconferencing, recording or broadcasting.

Auxiliary Input

The Aux input is an RCA jack accepting auxiliary-level (–10 dBV) input from sources such as tape decks and VCRs. There is no signal processing of the Aux input.

Preamplifier Gain

The SmartMixer has a substantial gain range, allowing it to accept a wide variety of micro- phones. However, if in some instances higher-output microphones are used for close talking, it may be necessary to reduce the preamplifier gain. This can be done by changing switch settings inside the unit. With the unit unplugged from its AC source, remove the two screws on each side of the unit and carefully lift off the top cover. Locate the internal switches designated on the circuit board by “SW2,” “SW8,” “SW14” and “SW20” (Figs. 4 and 5, page 11). A “control map” drawing will be found on the inside of the top cover. Changing the settings of these internal switches will cause a gain reduction of 10 dB for channels 1, 2, 3 and 4 respectively.

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Audio-Technica AT-MX351 manual Auxiliary Input, Preamplifier Gain
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AT-MX351 specifications

The Audio-Technica AT-MX351 is a versatile mixer that has gained a strong reputation amongst audio professionals for its performance and utility. Designed for various applications, from live sound to permanent installation, the AT-MX351 boasts features that enhance audio quality and ease of use.

One of the standout features of the AT-MX351 is its ability to handle multiple audio sources with ease. It features three programmable microphone inputs, making it perfect for settings where multiple speakers or performers are involved. This is especially useful in conference rooms, lecture halls, and places of worship, where different users may need to take turns speaking without the hassle of connecting and disconnecting microphones.

The mixer is equipped with advanced automatic mixing technology, which intelligently manages the audio levels from various microphones. This prevents feedback and minimizes background noise, resulting in clear and intelligible sound. The AT-MX351 utilizes Audio-Technica's proprietary Automatic Gain Controls (AGC) to ensure that the audio levels remain consistent, providing a professional sound experience.

In terms of connectivity, the AT-MX351 features balanced XLR inputs, allowing for secure connections that maintain audio integrity. It also includes unbalanced line inputs, catering to a wider array of equipment. The mixer offers both balanced and unbalanced outputs, providing flexibility for integration into different sound systems.

Another notable characteristic of the AT-MX351 is its user-friendly interface. The layout of the controls is intuitive, allowing operators to make quick adjustments on the fly. The clear LED indicators help users monitor signal levels easily, making it easier to identify any issues. This is particularly beneficial during live events where quick decision-making is crucial.

The AT-MX351 also incorporates a built-in limiter and compressor, which help to avoid distortion and maintain a consistent sound quality. This feature is especially important in environments with varying acoustic dynamics or when dealing with powerful audio signals.

In summary, the Audio-Technica AT-MX351 mixer stands out due to its robust features, including multiple programmable microphone inputs, advanced automatic mixing technology, and user-friendly controls. This combination of technology and usability makes it an ideal choice for audio professionals seeking reliability and high-quality sound in their applications. Whether for live performances, conferences, or installations, the AT-MX351 proves to be a reliable and effective solution in the audio mixing landscape.
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