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Meridian Processor 101

First of all, well done! If you're looking for the best in multi-channel digital audio processing, then you're looking in the right place: Meridian Audio produces quite brilliant domestic multi-channel audio processors (Bob Stuart et al. invented them, in fact).

So you're interested in buying a Meridian multi-channel audio processor, but don't know where to start? What are your options? Which model? New or second-hand? These are not easy decisions to make, particularly if you are looking to step on to the Meridian ladder for the first time with limited funds (which many many Hikers have done before you). This primer should help; if you still have questions after reading it, please ask them in the main forum; somebody will know the answer.

Note the following key to ballpark cost:

 $$$$$   $20,000 
 $$$$   $10,000 
 $$$   $5,000 
 $$   $2,000 
 $   $1,000 

HDMI

Let's get this of the way first. Meridian offers a four-input HDMI v1.3-capable switching solution with its HDMAX 421 in conjunction with a G6x or 861 processor. Meridian has not formally announced either an HDMI input solution for its processors or any likely timescale or roadmap. See the bottom section of this long post (under the heading "HDMI") for the latest comment from Bob Stuart. The latest rumour from the CEDIA 2008 Expo in Denver suggests that Meridian will produce an external HDMI-to-MHR conversion box which will provide support for up to eight (but initially only six) channels of (L)PCM over HDMI. Such a device will work with the 568.2MM, any G or C-series processor, and the 861 (version 3 onwards). A prototype box was supposedly in Denver, but no-one has reported actually seeing it!

Note that it is possible to modify suitable HD DVD, Blu-Ray, SACD, and non-Meridian DVD-Audio players so that they can pass multi-channel PCM to a Meridian processor, but this is beyond the scope of this primer. There is another possibility on the horizon (see this thread), but at this time it is just that: a possibility.

Time to move on...

Current processors (wot u can buy new)

861v4 ($$$$$)

The 861v4 is Meridian's reference processor. It is a modular design and, although it is sold in Analogue Theatre and Digital Theatre configurations, it is usually purchased in a custom configuration depending on the customer's specific source components and speakers. If you need a multi-channel analogue input, you add a card. If you need balanced analogue outputs, you add a card. Etc. Complete flexibility. Very expensive.

It features a DSP core capable of 750 MIPS (million instructions per second). Headline features include FIFO de-jittering of all digital inputs, upsampling of multi-channel PCM inputs (e.g. from a Meridian DVD player), proprietry decoding of Dolby Digital and DTS bitstreams, sophisticated DSP soundfield manipulation (DSP presets for stereo and multi-channel material), and Meridian Room Correction (MRC).

To date, there have been four incarnations of the 861. Historically, upgrades have been offered to bring the original 861 up to 861v2, 861v3, and 861v4 spec. On the Hitchhikers forum there is an expectation that 861 development will continue and further upgrades will be offered, but although this is likely it is not guaranteed as Meridian does not publish its development roadmaps. The next major upgrade is expected to involve an HDMI v1.3a input card (or equivalent solution) and associated internal software changes (e.g. to accommodate 7.1 input channels). No timescale for such an upgrade has been announced.

Note: The 861 does not have the processing power to decode a Dolby Digital (DD) or DTS bitstream and upsample the channels. To gain the benefits of upsampling DD or DTS soundtracks, a Meridian DVD player (or other suitable modified player) must be used to decode the bitstream and pass multi-channel PCM to the processor.

 Variant   Output Channels   Features 
 Digital   Balanced   Unbalanced   Room Correction   Video Switching   AM/FM Tuner   Multi Zone 
 861v4   Custom   Custom   Custom   Yes   No   No   2 (with TP00 card) 

G68 ($$$$)

The G68 is the poor man's 861v4! Joking aside, the G68 offers much, and in some systems probably all, of the 861 at half the price: The G68 shares the same 750 MIPS DSP core and processing algorithms as the 861. In an all digital system (digital sources, Meridian DSP speakers), arguably, you would not notice a difference between the G68 and 861. YMMV. What you sacrifice is the ultimate in performance on the analogue side, flexibility, and future-proofing. Having said that, internally, the G68 is a clean card-based design which should lend itself to upgrading.

On the input side, all G68s have two multi-channel 5.1 digital inputs and two multi-channel 5.1 analogue inputs (with very high quality analogue to 96/24 digital conversion using the same ADC chip as the latest 861 IA45 card). There are plenty of stereo digital coax, optical, and analogue inputs as well. The type and number of outputs vary according to the particular variant, as do the peripheral features such as analogue video switching, tuner, and multi-zone capabilities. See the table below for a comparison of the different variants.

Current G68 Variants

 Variant   Output Channels   Features 
 Digital   Balanced   Unbalanced   Room Correction   Video Switching   AM/FM Tuner   Multi Zone 
 ADV   10   None   8   Yes   Yes   Yes   3 
 AXV   None   4   6   Yes   Yes   Yes   3 
 XXV   None   8   None   Yes   Yes   Yes   3 
 AXD   10   4   8   Yes   Component   Yes   3 
 XXD   10   8   2   Yes   Component   Yes   3 

ADV, AXV and XXV

The latest incarnations of these variants have a USB input instead of the O1 optical input on older models; there are still four optical inputs. It is hoped, but not guaranteed, that an upgrade will be offered to owners of original spec xxV variants. The following caveat on the latest G68 spec sheet is not encouraging though, although it may simply be a disclaimer:

Meridian Audio reserves the right to amend product specifications at any time and we cannot guarantee that older models can be altered to conform to later specifications.

The "V" moniker refers to analogue video switching, but beware that there are limitations to this functionality (e.g. component switching is limited to 1080i and the only format conversion is from s-video to composite on the zone outputs).

AXD and XXD (USA only)

These are brand new variants for the USA market only. They are similar to the original AXV and XXV variants, but gain 10 digital output channels at the expense of composite and s-video switching. Switching of component video is retained.

Note: The G68D and G68J variants are no longer current models (see below).

The latest spec sheet is on Meridian's media site: http://media.meridian-audio.com/datasheets/g_series/G68-ds2-A4.pdf

G61R and C61R ($$$+)

The G61R is essentially a G68ADV in a smaller physical package, but without analogue video switching, tuner, and multi-zone outputs. Its inputs are identical to the current G68 models (with USB input) and its main outputs are identical to the G68ADV. The DSP code appears identical to the G68 (and 861 for that matter). The G61R has identical processing power to the G68 and 861 (confirmed in the CES 2009 Q&A session).

IMPORTANT! Do not confuse the G61R with the short-lived G61. The G61R is current; the G61 is not. The G61R has MRC; the G61 does not. It is very unlikely that an upgrade will be offered.

The C61R is a G61R in an installer friendly case.

 Variant   Output Channels   Features 
 Digital   Balanced   Unbalanced   Room Correction   Video Switching   AM/FM Tuner   Multi Zone 
 G61R   10   None   8   Yes   No   No   No 

Older processors (ex-dem and s/hand only)

861 / 861v2 / 861v3 ($$+ to $$$$)

To be written.

G68D / G68J ($$$)

 Variant   Output Channels   Features 
 Digital   Balanced   Unbalanced   Room Correction   Video Switching   AM/FM Tuner   Multi Zone 
 D   10   None   2   Yes   No   Yes   3 
 J(apan)   10   None   8   Yes   No   No   No 

The G68J was developed with the Japanese market in mind, but appears to have become a very popular variant. It is essentially a G68ADV without video switching, tuner, and zone capabilities, so it would work very nicely with a G91 (which itself has a tuner). Note that all G68s since the introduction of the "J" also have AAC hardware decoding on the main board. AAC is big in Japan, apparently... G68s prior to the introduction of the "J" do not.

G61 / C61 ($$$)

 Variant   Output Channels   Features 
 Digital   Balanced   Unbalanced   Room Correction   Video Switching   AM/FM Tuner   Multi Zone 
 G61   10   None   8   No   No   No   No 

The C61 is a G61 in an installer friendly case.

IMPORTANT! The G61 does not have Meridian Room Correction. It is very unlikely that an upgrade to the G61R will be offered.

568 ($) / 568.2 and 568.2MM ($$)

Approx £500 for a vanilla 568. This is an incredible bargain.
More details to follow.

561 ($)

Approx £500 for a vanilla 561. This is an incredible bargain, but nothing compared to the vanilla 568 which is now going for the same money. It's a mad mad world...
More details to follow.

565 ($)

The Meridian 565 is the one that started it all; and when I say all, I mean home theatre. Yes, really. The 565 was replaced by the 568.

As with subsequent Meridian processors, there were both software and hardware upgrades and you want to have one with the "Z3" card installed (see below). It has limited connectivity (1x optical, 1x SPDIF and 1x analog) so it needs a 518 or 562 to add inputs. There are no multi-channel inputs here (digital or analogue) and absolutely no prospect of them either!