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G91 (above) with G68
The G91As multichannel digital output allows
connection to a surround controller such as the
G68. Alternatively, the digital and/or analogue
multichannel outputs can be used to create a
powerful 5.1 surround system based on Merid -
ian DSP Loudspeakers or conventional analogue
amps/speakers - or a combination of the two.
Here the G91A really comes into its own: as the
heart of a complete surround system.
The G91A includes a powerful video processor
and scaler which can simultaneously provide
composite and S-video outputs, plus
progressive component video and up to 1080p
on an HDMI v1.1 output. It provides two
composite, three S-video, and one interlaced
component video input, all of which can be
routed to any of the video outputs with appro -
priate scaling.
At the centre of the G91A is a high-speed
computer-style DVD-ROM drive - the best type
of drive to use to ensure accurate data recovery
from all types of disc. The drive normally oper -
ates at standard speed; however, it is capable
of recovering data a great deal faster when
required, enabling it to make more attempts
to recover accurate data from a problem disc.
Because of this, the drive can perfectly recover
the data from almost any compatible disc.
Unlike other players that use a mechanical
approach to attempt to lower jitter by minimis -
ing drive vibration, the G91A employs a triple
buffering system to minimise jitter, maximizing
HF transparency and sound stage precision and
stability. The result of this sophisticated ap -
proach is that the players deliver ultra-low jitter,
with sound and picture quality second only to
Meridians 800 Reference DVD/CD Player.
The digital electronics as a whole are driven by
a new design of high-stability clocking system
which further reduces jitter and ensures that
the highest level of detail is recovered from a
disc. All digital data is accurately re-clocked, and
multiple power supplies ensure that digital and
analogue circuitry are kept separate.
The G91A includes a comprehensive front-panel
user interface which allows access to all the
features of the unit. The player can be set to a
standard Type which configures all the required
settings as required for a particular application.
In addition, an on-screen display (OSD) allows
you to configure specific settings individually.
The player employs Flash ROM memory for the
operating system, so software updates can be
downloaded from the Internet and installed via
a PC connected to the serial port on the rear
panel. The serial port also allows full remote
control and configuration of the unit.
The G91A provides three principal S/PDIF coax
outputs designated L/R, L/R Surround, and
C/LFE. These typically connect to Meridian
processors, or feed a stereo signal to a pair of
DSP Loudspeakers.
G91A DVD Audio/Video Player Controller Tuner
The illustration right shows the G91A at the heart of a compact, all-digital, Meridian-based stereo DVD system. The Meridian DSP loud - speakers take their feed from the G91As digital preamp outputs, with the speaker volume controlled by the G91As front-panel knob via the communications link, or via the remote. The G91A will also drive a stereo analogue system, for example with a G56 or G57 power amplifier and your choice of passive speakers, or active loudspeakers like the M420 in-wall designs.
In addition, the G91A will drive a complete 5.1 system comprising either digital speakers or analogue amps and conventional speakers - or any combination of the two (see panel opposite).
With three stereo analogue inputs and four stereo digital ins (two optical and two coax), the unit will support a wide selection of inputs, and when playing a multichannel disc as part of a stereo system, the surround information is expertly downmixed to stereo.
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If configured for MHR SmartLink they, or the ad -
jacent combined 15-way D-type connector, carry
high-sample rate encrypted data from DVD discs
for the highest fidelity of decoding and repro -
duction. The SmartLink also informs a connected
Meridian processor of the signal source, so that
it can switch processing modes automatically.
An additional S/PDIF digital output delivers a
stereo downmix or bitstream signal.
The G91A includes a preamplifier and integral
radio tuner. The main stereo analogue pre -
amp output is either fixed, or variable via the
front-panel knob which controls the Meridian
proprietary digital/analogue volume control - a
design similar to that used in the 800 Series and
DSP 8000.
Two tuner options are available: AM/FM and
DAB/FM. The former provides AM (LF/MF)
and FM (VHF stereo Band II) reception with
RDS/RDBS, and is fitted with its own 96kHz,
24-bit A/D stage. Digital signal processing
provides a sophisticated FM stereo blend/width
control which allows you to minimise noise
on a received signal. There is also a DSP-based
low-pass filter and a whistle filter for improved
AM reception. Alternatively, a version is available
with DAB Digital Radio (VHF Band III and UHF
L-Band) and FM. This option is described in a
separate sheet.
The G91A includes upsampling in stereo, which
allows digital filters to be placed far beyond the
range of human hearing, as well as offering
other audible benefits right across the audio
band, including improved transient response. All
processing is at 48-bit precision. This results in a
more open, transparent sound, tighter bass, and
a generally more musical sound overall.
To drive the multichannel analogue outputs, sig -
nals are upsampled to 176.4/192kHz for digital
to analogue conversion - DACs can offer better
performance at higher sampling rates - and
88.2/96kHz is used for the digital outputs, all at
24-bit word lengths.
Here again, sending 24 bits at high sample rates
via an S/PDIF link reduces jitter as compared
with the original 44.1kHz, 16-bit signal from a
CD, for example. In addition, high-resolution
digital outputs are encrypted, removing cyclic
components from the data stream and further
reducing jitter.
All these advanced digital processing features
are handled by a powerful DSP engine delivering
an impressive 150MIPS (million instructions per
second).
In addition, the G91A incorporates digital sur -
round decoding to allow the multichannel ana -
logue and digital outputs to be used to drive a
5.1 surround system directly, based on Meridian
DSP Loudspeakers and/or conventional analogue
amps and speakers.
The built-in surround processing system decodes
5.1 MLP, Dolby Digital or DTS soundtracks from
DVD-A or DVD-V discs, and Dolby Digital or DTS
data streams fed into the external digital inputs.
It will also synthesise a full surround image from
2-channel soundtracks on audio CDs, DVD-A or
DVD-V discs, or from the external two-channel
digital or analogue inputs, by extracting latent
surround information in the recording.
Several DSP presets are provided to allow you to
choose the type of surround processing used for
different sources. For 5.1 audio formats a Dis -
crete or Cinema DSP preset is selected automati -
cally, depending on whether the source is music
or a movie. For two-channel audio formats the
DSP preset can usually be switched between Tri -
field (recommended for music), Stereo (uses just
the main left and right speakers and subwoof -
er), or PLII (recommended for movies), using the
DSP key on the front panel or MSR+.
On the video side, advanced video circuit
designs, matched phase video filters, and a
broadcast-quality video encoder are employed
to deliver low-noise images of outstanding
colour depth and resolution. Separate ultra-
low jitter master video and audio oscillators
allow picture and sound to be independently
optimized, ensuring that the G91A DVD player
delivers breathtakingly clear pictures.
G91A DVD Audio/Video Player Controller Tuner
The G91A forms the perfect heart of an ana - logue or digital surround system, and the latter is shown here. In fact, the G91A will drive any combination of analogue and digital speakers in a surround system (though it is advisable to use identical speakers for left and right of each pair.
The analogue outputs are driven by 24-bit DACs that are upsampled to 176.4 or 192 kHz for maximum fidelity, and the digital outputs offer up to 24-bit, 96 kHz sampling - the highest quality available today from multichannel digital source material. The output level is controlled by the front panel knob or via remote.
The G91A supports almost any kind of video display device, whether composite, S-Video, Component (progressive or interlaced) or even the latest interfaces such as HDMI or DVI. Dif - ferent video inputs are converted to all formats, so there is only need for one display connection.
