Product Information

10
Elettromedia
62018 Potenza Picena (MC) Italy
T [phone] - F [phone]
elettromedia.com
audison.com
All specications subject to change without notice_19.A
Similarly, to crossover lters, graphic and parametric equalizers based on IIR lters
alter the signal phase behaviour with signicant effects on audio quality. A heavily
equalized signal is characterized by an unclear stereo image and lack of transients
denition. Audiophiles often classify this feeling as a veil that blurs the musical
message and deprives it of the necessary emotion. The use of FIR lters guarantees
an important result: the phase behaviour is linear, free from rotations or indecisions.
This also makes the use of lters with a very high slope (up to 48 dB / Oct) possible,
without altering the phase response. Such a high slope for the lter enables the
midrange and tweeters mounted on the a-pillar to work at lower frequencies without
any issues with power handling, thus raising the emission front. Therefore, thanks
to the FIR lters the advantages of three or multiple-way systems are completely
exploited taking in-car listening experience to a different level. When listening, a
system that uses FIR lters provides great clarity in transients reproduction, such as
the acoustic piano hammer strikes or the drums. The stereophonic image is deeper
and denite. Instruments in the virtual stage are more focused and seem to have
more space between them.
Even the intervention of any equalizer over the frequency response, when available in
FIR technology, does not modify the audio signal phase, allowing more precise and
detailed corrections without conditioning the audio quality.
FIR lters therefore provide a better audio quality. So why are they
used only by the bit One HD Virtuoso? Implementing a FIR lter
requires the DSP chip to work with an enormous array of numbers
and with much more complex calculations, and is therefore much
more burdensome than the one of an IIR lter. As a result, the
DSP Analog Device entry level chips of the "Sigma" family other
audio processors are built with do not allow FIR lters to be used
because the DSP chip does not have enough computing resources
to handle this and other features. In addition, the processor
control software that uses the SIGMA chips is generated using
the "Sigma Studio" graphic interface, which provides a series of
pre-set audio codecs to the developers and none of these codecs
have FIR ltering. The bit One HD Virtuoso is the only digital audio
processor for automotive use equipped with the SHARC series
Hi-End Analog Device Processor ADSP-21489. This processor
works with a 32-bit floating-point computing unit, a feature that
provides it with a dynamic range far superior than the inexpensive
xed-point "Sigma" used by other processors. However, the higher
EXCEEDING THE LIMITS
IMPOSED BY PHASE ROTATIONS
FLOATING-POINT SHARC DSP
computational power and precision of the SHARC series DSPs
requires expert hands to be exploited to the full. It is not enough,
as in the DSPs of the "Sigma" family, to use the supplied codecs.
That is why a development team with a deep understanding
of algorithms programming for digital signal processing is
needed. The experience in programming SHARC processors
that the Audison development team has built since 2006, with
the implementation of the bit One, has made it possible to reach
a new level of audio quality for the bit One HD Virtuoso. A new
software allows the user to exploit the whole power of the SHARC
processor by employing FIR lters on a 9-channel output platform
enabling the creation of high-performance audio systems up
to 4-way + subwoofer. The result is a quality of sound signal
processing which is deeply different from any other DSP. This
unique listening experience is achieved thanks to the excellent
work of the development team and to the state-of-the-art SHARC
DSP, raising audio quality to a level never reached before.