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FILTERS •
FEEDBACK CONTROL
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In addition to being painful to hear, feedback can also cause amplifiers to clip, and
can destroy drivers and loudspeaker components. While most feedback can be
controlled by proper microphone placement, resonant frequencies can be attenuated
using filters like parametric equalizers.
Low frequency feedback isn’t necessarily audible, but it decreases the system’s power
and responsiveness. By attenuating the low-end frequencies (low cut/high pass) not
needed for vocals, the XAP 800 system operates more efficiently because it doesn’t
need to allocate resources to produce low frequencies throughout the system.
XAP 800 Feedback Control System
The XAP 800 includes a number of highly customizable filters that are excellent tools
for feedback control. These filters boost or attenuate certain audio ranges,
compensate for poor acoustical environments, and generally fine-tune your sound
system. Some filters, such as pass filters, allow you to select a range of audio
frequencies above or below a given point and attenuate it, while others allow you to
attenuate specific frequencies. Filters are also excellent for use in canceling out
frequency ranges that cannot be transmitted through telephone lines, thereby freeing
up the system’s resources.
The XAP 800 features the following filters:
All Pass
: A filter that provides only phase shift or phase delay without significantly
changing the magnitude of the signal. Useful in custom crossovers designed to
compensate for loudspeaker driver deficiencies.
CD Horn Equalizer
: A constant directivity horn driver has an inherent 6dB/octave
high frequency roll-off. This device products a 6dB/octave boost to compensate. The
CD horn device is implemented using a high shelving filter. The level control is fixed at
+12dB, and is hidden.
High Pass
: Allows frequencies above a designated frequency to pass while
attenuating those below it. Perfect for attenuating low, rumbling noises like those
captured by a microphone when placed on a stage, table or in a microphone stand.
High Shelving
: Boosts or attenuates frequencies above a designated frequency while
leaving those below it unaffected. The transition between the spectrum above and
below the designated frequency occurs at a fixed 6dB/octave rate. When boosted, it
enhances the higher, more intelligible aspects of the vocal range. When cut, it is
excellent for avoiding resonant frequencies (feedback) and ranges of extraneous
sibilance (like a constant "ssssssss" noise).
Содержание XAP 800
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