CA 4D
|4 CHANNEL POWER AMP
CA 4D
|OPERATING INSTRUCTIONS
6 |
P a g e
The digital signals are processed by a floating point DSP. This DSP converts the 24 bit wide
integrated data files in a flow word of 32 bit mantissa to an 8 bit exponent, equaling a theoretical
dynamic range of 1500 dB. Overloads, scale noise, and rounding noise are impossible at this
resolution. The parameters available for adjustment, such as Delay and Room Equalization, have
direct access to the floating point of the digital signal processing which eliminates mistakes in
scaling.
EQUALIZATION
The most important function of the controller is to assure a flat frequency response and positive
phase relationship. In the course of preparing those programs every sound configuration had to
undergo numerous test runs in order to take measurements to evaluate and to determine the
many different conditions and solutions possible. This results in the best programs with optimal
results for each driver. KS Audio developed a FIR® (Finite Impulse Response) technology to create
the inverse frequency response and operate this via an onboard DSP engine comparing input
signals against programs pertinent to the cabinet and it's components, in order to execute a
complex digital filtering process. This results in the optimal equalizations for each driver/box and
system.
Additional to all this, the sound engineer is free to adjust the sound for a certain application and
venue by adjusting the program parameters such as “Shelving” and “Low Cut” filters. Please check
the program parameters for full details.
SPECIAL HIGHLIGHTS FOR THE SIGNAL PROCESSING
A short impulse in an analog equalizer is extended in the time domain and creates in the output
stage of the equalizer a post-oscillation of the impulse response. On top of all this, the mass of the
driver creates an additional post-oscillation initiated by the same impulse. Combined together
these changes in signal-motiontiming at the output stage leaves little in common with the original
signal. KS Audio developed the FIR (Finite Impulse Response) filtering technology, called FIRTEC ®.
This technology removes any of the delay time distortion and handles the time domain as well as
the frequency response.
The correction of the input signal is done immediately in the time domain, through a mathematical
convolution of the input signal and the impulse response of the digital equalization filters.
Conversely, traditional analog filter / equalizer technology tries to correct the frequency response
of the signal through various filter elements which degrades the original impulse signal response.
The new digital FIRTEC ® technology equalizes the signal immediately and corrects it to exactly
match the original impulse. This is a physical equalization of the frequency response in volume and
phase.
CROSSOVER
In reality, the analog filtering process tries to correct the frequency response of the audio signal
through various filter elements and as a result, degrades the quality of the signal’s impulse
response. The FIRTEC ® technology digitally equalizes the input signal immediately and corrects the
actual impulse of the signal. This is a physical equalization of the frequency response in volume
and phase. The cross over is optimized to be linear for frequency and phase (Bessel Filter). In analog
systems, phase shifts exist in between crossover points which can produce a result of near
cancellation of the sound pressure between systems when running various speakers in parallel (2-
way / 3-way systems). The KS Audio FIRTEC ® technology is based on a combined Bessel filter and
Differential filter process to yield superior results. This means the high frequency response is the
result between the low pass filter and the input signal. In consequence the result is an optimal
addition between the high and the low frequency cross over points. Instead of a phase shift as
