Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems G68 questions

Hello

Just acquired a G68ADV and trying to make the settings.

In the Room Correction section, I ran the program with a Sound level Meter connected to A8 (mic) and placing the SLM into the listening position.

the final result gave 0 filters and a flat line. I then noticed to have the following issue : Signal to Noise is poor (34Db) the minimum acceptable is 40Db for all.

I set the SLM weighting C and slow response then selected 90Db on the range.

Is there anything I am doing wrong ?

Second, trying to use the 12v trigger to switch on/off my power amp, and I do not know where I can find it in the menus (I found something on right click on G68 then properties then on source I select radio and changed trigger 1 to high, but it does not work, my power amp accepts 12V trigger)

Thank you

There are lots of things that can potentially go wrong with MRC. I would suugest checking the wiki as a first port of call

MRC Tips and Tricks

Regarding the triggers, its sounds like you are on the right lines but make sure the trigger is set to high for all your sources in the G68 menu. Also check that your trigger wiring is OK.

Lets start with the room correction.

1. Have you calibrated the system? Each speaker needs to be calibrated to the lowest level speaker. Ie, test each speaker one at a time in calibration mode to find which is lowest at 0db. Lets say all measure roughly 78, but one reads 73. You need to bring each speaker down to match the lowest level speaker, 73. this means the sub too.

If you are not properly calibrated, the SN can be off. ALso, make sure you have a realistic crossover setting. Twice the lowest level of the speaker is a good placed to start for music. Depending on your setup and preference, I generally don't change for movies default.

Now for the triggers, you need to double click the G68 on the first page of the products page in the configuration setup and go to sources. Each source has a setup for triggers, 1-2-3. You turn those on per source as they are needed.

If that's not too clear let me know.

Thank you both for your help, I was able to find the issue with trigger, I needed to set "High" for all sources (this is odd, my power amp is not declared as a source), so for DVD, PS3 etc. I had to set High for each trigger.

Regarding Room correction and calibration, I am sorry, I do not catch

What I did is the following:

1 Inserted in the Meridian program all my devices (Cablebox, PS3, Power Amp and 5 Analogue Speakers)
2 Linked all the sources to the radio and from radio to Power Amp and to Speakers
3 Speakers distance, One issue I have Defintive Tech UIW RSS II in-ceiling dipole speakers, they are 2 meters (6ft) from my listening position but above and not behind or sides.

4 Calibrated the speakers with the SPL meter to 80Db for each speakers, which gives me the following results:
Front Left +9.5 Db
Front Center +8Db
Front Right +8Db
Right Side +6.5 Db
Left Side + 7db

All Set Size to max and phase positive.
5 Room Correction, and this is where I get a 0 filter, but maybe this is the SPL Meter battery I need to change, I will buy new ones later today.

6 I did not touch the DSP Presets, tuner etc.

Hi,

Your speaker calibration sounds ok, but normaly it's done to 75db not 80db but that's fine.

Have you read the Wiki yet on running MRC? Please confirm, this is very important.

Did you have the SPL meter mounted on a stand?
Holding by hand or resting on the sofa does not given good results.

Regards,
Carl

Yes, I read the WiKi and I need to buy new battery for the SPL Meter. I do the measurement on the sofa but it is fixed and not pointing to the speakers.

I will redo the process tomorrow.

What I do not understand is the process suggested by SupreM see below

The process described is pretty much standard calibration. Have a look in the manual also.

I think he is describing when you can't reach, say 75dB, then you pick the lowest volume speaker and calibrate to that. Don't just arbitrarily pick, say 70db if they could all do say 73dB.

There are some differences in S/N depending what you calibrate too. And it will effect the level MRC measures at which can effect S/N and it will effect where you set the range on the SPL Meter as well.

Here is your problem number 1.

The MAX setting does not work well with room correction and calibration. Actually it sounds horrible during these. It is definitely causing an issue. Set all sizes to zero temporarily for calibration and and MRC.

I highly recommend taking the DB down to the lowest, which is the natural state of that left main. This way you are not "pumping up".

After the MRC is done, and saved, go back and adjust each to max size and store the settings. This will get you to where you need to be. The MAX setting is killing the SNR.

If you have positive 9.5 db on your left main to reach 80, I would reccomend setting all to 70.5.

Also make sure you have the SPL set appropriately and watch it as it registers during MRC. If you are below 75, you may wish to set the meter at 80.

Thank you all for your great help.

I had a chat yesterday night with a colleague that has owned a G68 for several years and he explained me the following:

He sets bass management, speaker distance but he does not enter any positive level value for the calibration (puts 0 or less).
He puts everything to 0db excepts -5 db for rears and if he feels the need for more level, He makes the adjustments at the DSP (cinema for movies etc..). He tells me that Meridian does not like positive levels in the calibration side.

That surprises me, it is in contradiction to all I have been said, what do you think?

I don't think you have understood what has been said. Noone is suggesting calibrating a speaker at >0db. With DSP speakers it is physically impossible to calibrate +db using the normal methods.

I'm not sure I have ever seen this advice before. I have had a lot of trouble with S/N on MRC and if this helps I will give it another go. I thought the speaker size setting only limited the bass in extreme circumstances and basically did nothing except in "overdrive".