Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems [G68ADV+BDP83SE]How to setup a 5.1 analog link ?

Phew !!!!!!!!!

I reckon bass management causes a lot of people headaches in lots of systems of all makes.

I really don't understand why Meridian doesn't give the possibilty to raise the SW level beyond 0db.
The Oppo player is doing what it suppose to do on its analog output (with a 10db lower LFE channel). It's the job of the pre-amplifier to harmonize the channel levels.

Doing that in the player isn't without risk for a pre-amplifier LFE input :

It is not really an option for the player to boost its analogue SW output, as it would be in danger of overloading a receiver's input circuitry when a maximum volume LFE signal appeared - feeding a 6 volt signal into a nominally 2 volt input. You might get away with it if the amplifier was purely doing an analogue passthrough, but it would overload any receiver with multichannel ADCs.

http://www.avsforum.com/avs-vb/showthread.php?p=8855640#post8855640


Serge.

What do you have for a Sub? Meridian is basically in digital domain and can't go above 0dB. In the digital domain it's supposed to stay at -10dB for head room purposes. In analog there is no reason to keep the -10db. So I don't think the Oppo should be attenuated by 10db on the analog output. That's just my opinion and understanding.

If you are running all analog on the G68 subtracting in calibration does no harm. You'll be canceling that out with the master volume when you bring it up. It's the same circuit/signal you're adjusting. So when your ear is happy, how you get there in the end is the same.

I find it hard to believe you will blow anything boosting the Oppo output. But I take no respondsibility

One JBL 4645C and one DIY sub with a WGTI15, the two amplified by a Crest Audio 8001.


In the digital domain, le LFE channel received by the pre-amplifier is supposed to be boosted with +10db. The head room is an old story :

http://www.hometheaterhifi.com/tech...hannel-in-51-digital-surround-sound.html

Serge.

Serge, you won't be mixing anything into the Oppo's sub/LFE channel, and I'm certain that the +10dB trim will be done in the digital domain and nullify the -10dB attenuation. In other words, the +10dB trim is exactly what you need.

I have read the manual of the last big Denon pre-amplifier.

http://usa.denon.com/AVP-A1HDCI-OM-E_101A.pdf

Page 34, with an external analog signal :

Subwoofer Level
Set the subwoofer level for playback.
Select according to the player in use.
[Selectable items] 0dB +5dB +10dB +15dB
We recommend setting to “+15 dB”.

With these possibilities, it can manage correctly the 5.1 analog output of the BDP83 with every setup. If you let the player do the bass management, the needed LFE boost is +15db instead of +10db with no bass management.

Serge.

Serge, I'd ask your dealer to ask Meridian. Applying -10dB or -15dB on the sub channel is the norm for players with analogue outputs.

However, I still think it would be better to do this in the source.

I know no Meridian dealer


Yes. But i believe the Denon example is the good answer. They have split the LFE management in two part : analog domain/digital domain.

If you take a look at the G68 documentation :

Note: Multichannel analogue sources may have subwoofer level
outputs that vary by up to 10dB, so it may be necessary to reduce
the LFE level to give correct bass integration; see DSP presets, page
37.


Page 44 :

Cinema
The Cinema preset is recommended for listening to multichannel
movie soundtracks when no further processing is required.
Discrete
The Discrete preset is similar to Cinema, except that it uses the
Music speaker layout and sets the LFE level to -10dB.


Meridian has choose the exact oppposite way to manage the LFE level in the case of an 5.1 analog input. (same thing in the last 861 documentation)

The management of the level in the player is just there to calibrate the speakers not to compensate the level differences between each sound format. This why it is not possible to add +15db on the LFE channel in the player (and the +15db is needed if you choose to do the bass management in the player)

Serge.

I wouldn't say that, but it is confusing. My understanding is that with movies (Cinema preset), Meridian boosts LFE by 10dB, but reports it as 0dB (which is the correct thing to do), because, to allow an extra 10dB of volume, the LFE movie channel is recorded at -10dB vs. the other channels. With music (Discrete preset), that boost is not applied as it is assumed that the LFE channel in the recording is at the correct level with respect to the other channels.

You are correct in that Meridian doesn't provide a means to compensate for players that attenuate the analogue sub channel. However, you said earlier thatSo you only need +10dB of trim (which the Oppo can do) if you set all speakers to large in the Oppo (which turns off bass management in the player).

I will make some measurements this week-end to see if the Cinema preset is doing a +10db boost or not.

Serge.

Result of the tests :
- the Cinema preset does nothing to the LFE signal level.
- the Discrete preset apply the -10db correction

I have made the comparison to the same DTS signal sent through the Oppo HDMI output to my scaler, then to the G68 optical input.
There is 1-2db missing with the Cinema preset and 10db missing with the Discrete preset

For me, Meridian has missed something with multi-analog treatment. Ok, it's an old pre-amplifier now. But it is strange that even the last version of the 861 and the new G68 are also unable to do such LFE level boost. Because it seems very easy to change.

Serge.

Hi Serge,

I would expect the difference on the LFE channel between Discrete and Cinema to be 10dB.
With Cinema adding 10db (to boost the movie LFE track up to the correct 0db level) and Discrete adding nothing as the music input signal is already at 0db; relative to the other channels.

May I ask, in detail, how these test where performed and measured?

Regards,
Carl