15
Processing Concepts
Why our processing sounds better
The Unity AM utilizes advanced digital processing techniques that expand the performance ability of
the system. A single bit, digital gain block is employed to provide all dynamic processing functions.
Processing functions are a true representation of any gain changes that are implemented. This allows
the gain block to create dynamic level changes that are determined by the control circuitry only. This
is unlike typical analog processors where unwanted sonic artifacts are attributable to the limitations of
the gain stage.
The crossover networks, filtering, and NRSC low pass filter are all of a true phase linear design.
Sonic integrity is maintained in both frequency response and group delay/harmonic response.
A key important feature to the sound of the Unity AM is the unique
Linear Response Algorithm
(LRA)
. This function provides intelligent high frequency control before the insertion of pre-emphasis.
Competing systems provide high frequency control after pre-emphasis, which compromises sonic
clarity and can sound dull, harsh, or lacking in natural content. LRA, on the other hand, yields
improved transparency in the presence and high frequency bands. As the ear is more sensitive to
fatigue and distortion in these ranges, thanks to LRA the Unity AM sounds more musical.
Processing designed for the ears
We won’t pretend that we have the answers to all of the audio processing questions that exist in our
industry. But we do think that the experiences and research of Frank Foti and our other engineers
have provided us with an understanding of many processing issues. What follows are some concepts
that should help guide you through the operation and adjustment of the Unity AM. These issues are
important because no matter how much we tell you in the manual, not matter how much time we
spend speaking with you on the telephone, and even if we visit you, you are ultimately responsible for
making the Unity AM sound best for your stations format and requirements.
What device is used to recognize the perception of audio loudness? If you answered the ear, you are
correct! The ear perceives loudness by sensing how much
average (RMS) level
is present in the ear
canal. The higher the average, the louder the perception. On the other hand,
peak level
by definition
is very low in average level and therefore less noticeable to the sense of hearing.
