Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems Re: Trifield Width not working, the fix and ongoing saga

Bump - no answer from the Mothership yet. I don't want this issue to dissappear until they respond.

Given ncpl's comments about mothership awareness I'm going to make this a sticky. No need to bump it then...

For my part, I've obviously been skim-reading this thread too fast as I didn't appreciate the fact that, basically, Trifield may be broken in all of the recent processors.

Checked my set-up (518 into 568.2 v2.5 into mixed analogue/DSP speakers) - no change noticable with the width setting. This used to be really obvious with my 565z3v6

I don't think it's broken but it's just much more subtle an adjustment and depending on your setup it may be more subtle than another.

But I would like to understand better.

I wonder if it broke when upsampling was implemented? Perhaps someone might try it with HS=No (though I imagine the whole code would be broken)?

I have tried it with HS=No. Still no change.

Mine is HS=No

In earlier processors we allowed Trifield to operate for configurations with no Centre channel. However we felt it was not of any interest because it amounts, in that case, to a width control in Stereo which we don't provide. At some point we changed the processors to revert to Stereo in the Trifield-no-Centre case.

We really don't think that there is an error in current Trifield code (G61, G68, 861). There is thorough fully-automated process to check each code build. However to be certain we will schedule a check. We have rechecked 568 and 568.2 and they are to spec.

In Trifield, Width changes the signals fed to L & R and the degree to which this is audible will very much depend on the content. Strictly the Width control responds to the magnitude of S = (L-R). To hear this best use open spacious recordings.

Meridian,

With no center channel speaker (phantom center) Trifield is definitely operative on my My 568.2 (Both build 2.12 and 2.5 beta 9) and different than Stereo. At a minimum, the rear channel operate in Trifield, recovering ambience.

I have tested the width adjustment on the 568.2 using NO center speaker and using a center speaker. I used recording that had exhibited an extreme level of change (in previous firmware versions) when width was adjusted, and now they exhibit NO change. I tested this phenomenon with and without a center using both firmware versions listed above.

So, something else has changed that is significant. As I stated in posts above, this probably happened when I had my 568.1 upgraded to 568.2 - I guess I was simply looking to find out if anyone knows when and why the change occurred. I didn't follow up on it at the time I upgraded beccause I wasn't using a center channel at the time, and figured that width, like depth, was not practical without the center speaker. Upon adding a center channel, I was surprised to find that it still didn't work.

John

I was playing around with a bunch of tweaks last night and figured out (rather noticed this behavior).

A few folks including myself noticed how little effect Depth setting has in Trifield.

Well I put my head like 2 feet forward and it behaved like it used to.

Where you'd hear significant changes on every step.

But in the sweet spot it has almost no effect.

I'm not sure this is a good thing or a bad thing.

It always bothered me when every step changed a lot and it would almost go in and out of phase on each step. 0,1,2,3 sounded in phase and 0.5, 1.5, 2.5, 3.5 sounded out of phase so it was hard to tell if you were moving in the right direction.

So I wonder if as you change this parameter you are bending the image around and as I have things setup for the sweet spot that I am either outside the "listening volume" of processing or I'm on some sort of pivot point. Were as when I'm in the "listening volume" there are multiple wave fronts swinging past my ears as I change the depth.

I noticed other DSP modes were not nearly as sensitive to this insentive depth adjustment mode.

I also played with DSP Super mode. It is pretty cool you can switch to 4 Speakers and listen with out the center channel.

The question for me, George, has always been 'what defines the sweet spot?' The physical positioning (geometry) of the speakers, or some processor parameter(s)?

When this is resolved, then we can, perhaps, meaningfully investigate/discuss variations in DSP parameters such as depth, width etc?

Good observations, though!

Exactly !! And is what you thought was the sweet spot the sweetest.