10
Overview
www.tecnare.com DMA-8X8 DSP MATRIX | rev.:1.0
DMA-8X8
2. Technology Overview
2.1. Introduction to the Technology
The DMA8X8 is equipped with several core technical features to facilitate the work of audio engineers.
DSP-based remote audio hardware is routed, processed and controlled via computer. This Manual mainly introduces
the techniques used to achieve the goal.
DSP Software is a Windows-based application, which is used to do the conguration and control of
DSP hardware. DSP Software has 16 built-in presets, and the modules and sequences for each preset can be exibly
designed in accordance with the designer’s requirements. When the design is complete, it can be stored for future
use. The sequences and parameters of DSP Controller’s built-in processing modules accord to most of the applica-
tion scenarios without any change.
DSP Software is a full-featured application, including the parameter adjustment and peripheral acces-
sory settings of all modules. The most interesting part is the user interface, which allows the engineer to customize
the user interface so that the integrator can edit it or the onsite technicians or end users who have no idea of relevant
techniques can operate it. Superior safety functions make it possible for the end users to access to the controls al-
lowed by the engineer or designer.
2.2. Float Point DSP
The DSP device achieves a leading sonic performance by the use of state-of-art converter, a 4th Gen-
eration Analog Device SHARC DSP, enabling 32-bit and 40-bit oating-point processing. Floating point processing
provides prominent advantages for the users in terms of sound quality and usability.
2.2.1. Fixed-Point Processing Limitations
Fixed-point processing has its own disadvantages. If there is a signicant change in gain, data loss or
more severe situation may occur, including clipping distortion. For example, for the processing of 24-bit xed point-
based audio signal, in some cases, if you attenuate the signal to 42dB, the new signal only includes 17-bit informa-
tion. For example, for the processing of 24-bit xed point-based audio signal, in some cases, if you attenuate the
signal to 42dB, the new signal only includes 17-bit information. Due to gain attenuation, 7-bit information will get lost
forever.The worse is the clipping distortion. For a signal nearly close to 0dBFS, the signal will be clipped at 0dBFS
and the audio distortion will occur. Even if the signal level is adjusted to below 0dBFS through post regulation, the
clipping has occurred, and the distortion still exists. Fixed point processing can help to create some headroom above
0dBFS. By doing so, some bits have to be abandoned. For example, if a 12dB (2 bits) headroom is created, a 24-bit
system actually only has 22 bits.
2.2.2. Floating-Point Processing
On the contrary, by taking advantage of oating-point processing, no matter what the signal level is,
all available bits are uniformly distributed to the signals. Basically, the oating points use some bits as indexes to set
up a general signal level and distribute the remaining bits to signals with independently stored level. As a result, no
matter what kind of level (from -200dB and 200dB below to 0dBFS above, the stored signal’s accuracy is optimized
without clipping distortion. SHARC provides 32-bit and 40-bit accurate processing; through 32-bit processing, 25 bits
are distributed to storage signals no matter what its signal level is. This means that, based on at least 1-bit low level
signal, its accuracy is always signicantly superior to 24-bit xed point processing. Through expanded 40-bit accurate
processing, 33-bit storage signal can be achieved.
2.2.3. Practical Signicance
What’s the practical signicance of oating-point processing for the users? The gain stages between
multiple modules can be ignored. If the signal level of a module is reduced by 50dB and is then restored to its origi-
nal value through another processing, data loss will not occur. In the xed-point system, the users must check other
signal levels before sending it to A/D converter because all digital-to-analog converters adopt xed points. In DSP
