Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems MConfig question - anybody has tried RC just for some speakers?

My system is 7.1 with a G68.
Normally, Mconfig calculates a maximum of 7 filters per channel (its maximum under automatic room correction with 8 speakers - 7x8=56) and leaves a min of four filters unused.
I would like that Mconfig creates a max of 15 filters automatically for the fronts, center and sub; surrounds should have no filter applied.
I tried what follows.
Now, in order to have Mconfig automatically creating filters just for some speakers only, I have tried to eliminate surrounds, apply room correction and indeed I have 54 filters created for 4 speakers.
When I try to add surrounds, Mconfig says that RC would be lost - and indeed I lose it.
Now, how could I try to have this done?
Should I add surround using the "More" button on G68?

Under the RC tab, use the right mouse click in the empty box (or where you just took your measurement) and select the "new" option (if you have no measurements) or "measure" or "remeasure" options if you already have taken a measurement. A pop up box will allow you to select all speakers that you want to apply RC.

Hope that helps.

doing so will simply re-measure speakers.
but when calculating filters, Mconfig will always check for filters for all installed speakers.
Any help?

No it does not, you need a new profile with only the selected speakers. Don't remeasure an existing profile.

Also If you do measure, say you front with more available filters. I think you can jot them down and add them later to your 7.1 profile and use up those 4 filters. Tedious but possible. You might be able to delete a few less critical filters from yor surrounds too.

It is possible to do this manually, George, and eventually I will do it, but it is a real pain to manually insert 3 values per filter per 60 filters music and 60 filters cinema = 360 numbers...

why don't you just decrease the RTC figure from say 300 to 250 or even 200 this will make it add more filters.

because it wont' change the maximum number of filters per channel, so when you've reached 7 filters with 8 channels, that's it.
Another suggestion could be to use the G68 itself to add more speakers after room correction has been downloaded onto it, but I fear it will be losing RC data anyway.
any advanced/power user to chime in?

The maximum number of filters per channel is 10, up to a maximum of 60 / filter set. You want to do 15/channel and that simply isn't within the limits of MRC at this time. Keep in mind that you are dealing with time sensitive operations and it is likely that going beyond 10 filters/channel exceeds the ability of the DSP core to handle the calculation load in the time window allocated.

As for MTAT's suggestion, the problem with defining a filter target below your room's midband RT60 (which is what the default target is for filters) is that you tend to end up with subjectively too little bass as MRC tends to get too agressive. At least that's been my experience. YMMV.

Best,

No, John, the maximum number is 20.
Try and build a 2.1 config file and you will find it out. Just add manually more filters and you will get a 3x20 filters config.
With 4 speakers maximum per channel is 15 filters.
More generally: maximum number of filters per channel is 20; maximum number of automatically calculated filters per channel depends on the number of active channels: here are the maximum ratios betweend active channels and max auto filters: 2/20 - 3/20 - 4/15 - 5/12 - 6/10 - 7/8 - 8/7
If you don't believe me, just try this out and see what happens.
With 8 active channels, Mconfig will never add more than 7 filters.

My automatically-calculated target decay time is more than 800 ms, due to the large and odd dimensions of my listening room, and highly lively walls and ceiling. And - even at 800 - no filter is created at all.
To have Mconfig creating more filters I have to get as down as 400ms. And even then it creates filters only as described above.

I simply would like to have my system use room correction only with front speakers and sub.
I can do this manually but it is very time-consuming.
Any suggestion on how to manage my unit and / or Mconfig to reach the above mentioned result?

Paolo,

You've just said that you have an 8 channel system defined, and you're asking the system do something it isn't designed to do, ie to only provide filtration on the front trio of speakers (not something I would personally consider) and to do so such that the target decay time is dramatically lower than the midband.

To do so is going to dramatically skew your results so that your midband is going to "hang" in the room compared to your low frequency, especially when you introduce the level of disparity that you are talking about introducing.

To be honest with you, I think all of this is window dressing until you work on the room and get some room treatments installed. They needn't be ugly, in fact some of the RPG products are lovely (and priced that way too). Until you do so, this is all pretty much an intellectual exercise.

Best,

John,

I don't think there is anything wrong with choosing speakers. Meridian does each speaker individually. It may well be one speaker with more filters over another is justfied.

I find most problems below 80 Hz. So for example is may be well worth applying 20 Filters to your full range speakers and no filters to your small speakers.

I also think Paolo is complaining that allocation of filters is a little bit too simplified and wastes 4 filters that he'd like the system to automatically use.

You got my point completely.
Fronts and center are full range.