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AirAura X1 / Dec 2016
G E N E R A L I N F O R M A T I O N
The X1 utilizes an internal base sampling rate of 192 kHz. Far higher sample rates
are used where it is beneficial to do so, such as within the X1 clipper. A 24-bit, 144dB
internal dynamic range signal path allows audio to be processed with extreme precision.
The single front panel touchscreen and control knob allows users easy operation of most
key controls to set up and adjust the processor.
All Wheatstone products are designed and manufactured by Wheatstone in its Corporate
Headquarters in New Bern, North Carolina, USA. This large, state of the art facility affords
complete control over product quality during every step of the manufacturing process. In
order to maintain the high product quality standards that Wheatstone is known for for over
40 years, no offshore manufacturing is utilized.
If during installation or setup you find that you need assistance or advice, please
feel free to contact our technical support folks at (252) 638-7000 or email us at:
X1 Feature Overview
The X1 digital audio processor has been designed to separately process audio for
conventional analog FM and digital HD radio signals. Sharing the four‑band parametric
equalizer and intelligent five band leveler with iAGC, the FM and HD paths are equipped
with individual “program aware” 10-band limiter sections and peak controlling processors
which have been optimized for the respective broadcast mediums.
The X1’s five band leveler incorporates Wheatstone’s specialized iAGC (Intelligent AGC)
algorithm. and operates through a proprietary technique called Density Compensation™.
The Density Compensation™ algorithm utilizes real‑time analysis of the pre and
post-processed audio, and data from the processing controls as the user has adjusted them,
to invisibly manage the user set spectral balance and program density. The output of the
five band leveler can then be patched to an external ratings encoder device. Upon return
to the processor, the audio is then split into two signal paths, FM and HD, each equipped
with our 10-band “program aware” limiter.
The FM signal path is equipped with a newly refined FM clipper. Borrowing a little
from our FM-55 audio processor, this new FM clipper works with the 10-band limiter to
automatically determine the best course of action to maintain loudness and clarity. The
result is a higher average level of audio without the traditional tradeoffs you would find
in other designs that were “trying” to be loud.
A digitally perfect stereo generator follows the clipper and provides two multiplex
composite stereo outputs and two SCA inputs.
The X1 is also fully compatible with exciters that accept composite audio delivered over
an AES connection. Wheatstone’s baseband192 system includes audio and subcarriers up
to and including 67kHz in an AES format. This system eliminates the need to transition
back to analog when using the built in stereo generator in your audio processor. It also
maintains a complete digital path without sacrificing loudness or having to use the stereo
generator built into the exciter.
The HD signal path is equipped with its own 10-band limiter followed by a smart look-
ahead final limiter with adjustable operating parameters which allow program density and
peak control to be set as desired. The HD path’s digital and analog outputs may be swapped
left for right as well as phase reversed if needed.
