Search results
Results From The WOW.Com Content Network
Automixers balance multiple sound sources based on each source's level, quickly and dramatically adjusting the various signal levels automatically. [2] Automixers are used in live sound reinforcement to maintain a steady limit on the overall signal level of the microphones; if a public address system is set up so that one microphone will not feed back, then, in general, the automixer will ...
To maximize gain before feedback, the amount of sound energy that is fed back to the microphones must be reduced as much as is practical.As sound pressure falls off with 1/r with respect to the distance r in free space, or up to a distance known as reverberation distance in closed spaces (and the energy density with 1/r²), it is important to keep the microphones at a large enough distance ...
Here, the still-mic-level signal enters into a microphone preamplifier, which boosts the signal voltage to line level. For this example, the microphone preamplifier is built into a mixing board. It is typical for a mixing board to include a line trim after the preamplifier. This allows the amplitude of the now line-level signal to be adjusted.
For sound reinforcement in live shows, mic bleed can make it hard for the sound engineer to control the levels of the different instruments and vocals onstage. For example, if an electric guitarist's loud amplifier is bleeding into the drum and vocal mics, it may be hard for the sound engineer to reduce the volume of the guitar in the onstage mix.
In both fields the amount of gain is measured in decibels at or just below the point at which the sound from the speaker driver re-enters the microphone and the system begins to ring or feed back. Potential acoustic gain (PAG) is a calculated figure representing gain that a system can support without feeding back. [1]
This means that (1) moving the microphone closer to the sound source increases the signal level produced by the microphone, and (2) moving the microphone further away from undesirable noise sources will diminish the amount of noise in the microphone signal. Microphone placement is therefore an important aspect of gain staging [citation needed].
The internal electronic circuitry of an active noise-canceling mic attempts to subtract noise signal from the primary microphone. The circuit may employ passive or active noise canceling techniques to filter out the noise, producing an output signal that has a lower noise floor and a higher signal-to-noise ratio .
Another type of normalization is based on a measure of loudness, wherein the gain is changed to bring the average loudness to a target level. This average may be approximate, such as a simple measurement of average power (e.g. RMS), or more accurate, such as a measure that addresses human perception e.g. that defined by EBU R128 and offered by ReplayGain, Sound Check and GoldWave.