Pioneer VSX-56TXi - Manual (Page 2)

wide, so those of you interested in purchas-
ing should be sure that your equipment
rack can handle its 18 5/16-inch depth.
The back panel is somewhat sparsely
appointed in terms of digital connectivity. I
feel that the number of digital inputs should
be larger than provided for a component at
this price level, since our systems are intro-
ducing more digital sources as time march-
es forward. Provided are two TOSLink opti-
cal inputs, with default assignments of
TV/Sat and CD-R/Tape 1. Two S/PDIF coaxi-
al digital inputs are on the back panel, with
default assignments of DVD/LD and CD
also available. Should you be blessed with
a mismatch, a converter will need to be
employed. Upping both digital input con-
nectors to three of each would likely handle
most end-user environments where the
VSX-56TXi is used.
Analog-only inputs for line-level audio
sources are also a bit shy but not to the
point of being troubling. Three stereo ana-
log audio-only inputs are provided for CD-R,
MD/Tape and CD. In addition, those with LP
playback capability will be pleased to find
an MM-capable phono stage, with ground-
ing also provided. There are four A/V inputs
provided and each has stereo audio, com-
posite, and S-video connectivity. A pair of
assignable component video inputs is also
available. A single set of multichannel analog
inputs (7.1) are also included so that a single
multichannel disc player can be connected
via analog input. In addition, a pair of assign-
able component video inputs are available.
Analog tape loops are well accounted
for with a pair of audio only outputs avail-
able. In addition, two video tape loops,
with stereo audio, composite, and S-video
are provided. A pair of digital audio out-
puts via TOSLink are also included with the
VSX-56TXi
The VSX-56TXi carries the final “i” in the
model designation to indicate i.Link capabil-
ity. i.Link (FireWire, IEEE 1394) is a specific
implementation of FireWire 1394a, which
allows for the uncompressed encrypted
transfer of audio streams, including high-
resolution DVD-Audio and SA-CD in their
native forms. Assuming you have an appro-
priately equipped player, a single cable can
be used for the transfer of all audio instead
of multiple cables. In addition, a USB Audio
input, capable of accepting MP3, Windows
Media Audio, and uncompressed PCM is
also available.
i.Link was a bit troublesome in its opera-
tion, and I need to take a few moments out
to tell you what the limitations are. When
setting up the VSX-56TXi there is a menu
option for SA-CD setup, which contains a
parameter for SA-CD direct mode. With SA-
CD direct mode off, all SA-CD material will
be played back as stereo only, but you gain
the ability to use MCACC and bass man-
agement when not played back in direct
mode. This is even true when playing back
the multichannel tracks on surround SA-
CDs. With SA-CD direct mode on, you can
listen to surround SA-CD tracks, but you
lose MCACC. DVD-Audio functions a little
bit cleaner, likely due to the ability to direct-
ly process the PCM data. MCACC and bass
management were available with 24-bit/96
kHz stereo and surround discs and 24-
bit/192 kHz stereo discs. For DVD-Audio at
24-bit/48 kHz and 24-bit/96 kHz, all DSP
functions were available, however, at 24-
bit/192 kHz stereo discs only bass manage-
ment was available. This would indicate that
DSP horsepower is a limiting factor.
Operating on 24-bit/192 kHz data requires
four times the DSP horsepower; you have
twice the samples to work with and half the
time-window for the operations.
The binding posts on the VSX-56TXi are
decent, though not outstanding. While it is
possible to use bare wire or spade lugs,
given the tight spacing of the posts the best
candidate is the “good old” banana plug.
This isn't a problem for me, as all my loud-
speaker cables terminate with banana
plugs. The spacing between plus and
minus posts is at 1 inch, so attached dual
banana plugs generally won't work. Once
connected, the banana plugs were gripped
tightly, and I never had issues with the con-
nectors detaching accidentally.
Digital Topology
Receivers and preamp/processors are
brought to audio life by their digital stages.
There are a variety of solutions available,
and some of the process is in selecting the
appropriate components to achieve the
intended sonic goals, while not exceeding
the overall sonic goal of the product. Digital
to analog convertors are the last piece of
the puzzle, and they are responsible for tak-
ing the output of Digital Signal Processors
to convert the signal to an analog voltage,
which is used to drive a power amplifier
stage. In the case of the VSX-56TXi, there
are four stereo DACs employed. For the first
six channels (Front L/C/R, Subwoofer, Side
L/R) the Asahi Kasei Microsystems AK4383
is used. The AK4383 is a maximum 8x over-
sampling Delta-Sigma Modulation DAC
capable of decoding PCM input up to 24-
bit/192 kHz, as well as natively decoding
DSD (from SA-CD). Performance specs on
the AK4383 indicate a THD+N of -94 dB,
with a signal-to-noise ratio (S/N) of 110 dB.
This approximates 19-bit performance.
While not quite state-of-the-art for DAC per-
formance, the VSX-56TXi isn't priced in the
state-of-the-art category either. The back
surround channels (used only for DTS®-ES
[Matrix and Discrete], DTS: Neo6, Dolby®
ProLogic
® IIx, and Dolby Digital Surround
EX™) are handled capably by the
AK4382A, which has comparable specifica-
tions to the part used for the main channels,
but lacks DSD support, which is not neces-
sary at present.
Digital Signal Processing is accom-
plished by a pair of Freescale (Motorola)
56367 DSP chips. The DSP56367 is a com-
mon part and is used by many in the indus-
try. In this case, the first DSP56367 is used
for traditional DSP functionality (lossy format
decoding, matrix decoding, proprietary DSP
fields, time alignment, bass management).
The second DSP is used exclusively for
MCACC, to implement the equalization system.
It is possible to apply DSP to analog
inputs, and analog to digital conversion is
provided by the Asahi Kasei Microsystems
AK5380 ADC. The AK5380 is a stereo delta-
sigma modulator ADC, with output sampling
up to 24-bit/96 kHz with an S/N ratio of 106
dB and the ability to operate cleanly, even
in relatively high temperature environments
approaching 200 F. By sampling at 24-
bit/96 kHz, this allows for high fidelity to the
analog input prior to DSP application.
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