T+A Elektroakustik SADV 1245 R - Manual (Page 49)

49
SACD Operation
CD/DVD and SACD discs have a totally different data
structure.
For a CD or DVD recording the analogue signal is sampled
at a high rate (44.100 or 48.000 samples / second). The
audio signals have to be bandwidth limited before the
sampling process to get rid of signal components above 20
kHz because these could not be correctly digitized.
The 20 kHz bandwidth limiting is not necessary for SACD
recordings. It is thus possible to record and store audio
frequencies up to 100 kHz on SACDs. However, all SACD
recordings use a process call “noise shaping” to achieve a
dynamic range comparable to CD/DVD systems. This
noise shaping leads to a substantial amount of high
frequency noise in the range 40 ...100 kHz.
There is a practical problem with the noise shaping; the
high frequency noise associated with SACD recordings
can not be handled by all amplifier and speaker systems.
In some of these the high frequency signals contained on
SACDs lead to distortion and thus degrade the sound
quality. In such cases it is necessary to limit the bandwidth
of the system to about 40 kHz. This would mean to
sacrifice the main advantage of the SACD system.
To get the best possible performance out of your HiFi
system, the SADV 1245 R offers analog and digital signal
processing means to tailor the analog output signal exactly
to the requirements of your amplifier and speakers.
These processing means consist of 4 different digital filters
with different bandwidths and different stop band
attenuations. (OVS standard, 1, 2, 4). Additionally you can
select the 'WIDE' bandwidth mode for the analog output, if
your system is capable of handling frequencies up to
400 kHz.
With the OVS and WIDE buttons on the front panel you
can experiment and find the combination of oversampling
and analog processing that delivers the best sonic results
with your equipment.
 Amplifiers are very linear devices having a very wide
bandwidth. So you can use all possible OVS/WIDE
combinations without limitation. We recommend a wide
bandwidth configuration using OVS 1 or 3 with our amps.
Standard OVS
This filter introduces a slight limitation of the high
frequency bandwidth. It is suited for most amplifier /
speaker systems.
OVS 1
This filter features a wider frequency range. Good
amplifiers with at least 100 kHz bandwidth are required.
OVS 2
This filter has the narrowest bandwitdth and is
recommended for amplifiers with a frequency response
<50 kHz.
OVS 3
This filter introduces no bandwidth limitation of the audio
signals. A very good amplifier / speaker combination
which can handle signals above 250 kHz without
problems is required.