Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems Difference Between Trifield & DLII Music?

Can someone provide an honest and bias-free explanation on the 'superiority' of Trifield over Dolby Pro-Logic II Music?

Whether looking at products from Naim, Arcam, or Linn, with DLII Music there are adjustable user parameters for 'Dimension', 'Centre Width', and, 'Panorama' (all accomplished in DSP).

Dimension adjusts the soundfield either towards the front or rear. Centre Width allows variable adjustment of the centre image either from all three front loudspeakers in varying degrees from 20.8 to 69.8; from just the centre channel, or splits the signal equally between left and right. Panorama extends the front centre image to include the surround speakers for a 'wrap-around effect' with side wall imaging.

Trifield, on the other hand, renders a two-channel signal using Ambisonic principles between left-centre-right channels. It can also be used to generate more rear speaker feeds for surround decoding from two-channels of Dolby Digital - but not, it seems, from conventional stereo signals.

So, from those of you with real experience of both, what makes Trifield better than DLII Music?

Will happily leave that for lwang....

Tri-Field is elegant sum and difference maths whilst Dolby Pro Logic Music is heavy duty DSP.
The summed centre from TF should stablise the stereo
image with a slight drying of the acoustic.
The Dolby processing will be less acurate???

Answers please on a postcard .

Did you knock on my cave ncpl?

Anyway, Trifield is based on Ambisonic principle of wavefront reconstruction where it utilizes the summation of the waves from multiple speakers in order to simulate a phantom sound source situated at any point between the frontal 3 speakers and the resulting wavefront that gets reproduced by it. Since all the speakers work in conjunction, you won't have that sound localizing to a single speaker effect.

While the whole concept of DPL and all its subsequent variations is trying to detect the the location of the sound source and try to pan-pot that sound between any of the two speakers that's nearest by. It has a tendency to steer the sound toward any of the single LCR speaker, causing the sound to be completely localized to that single speaker, which would sometimes cause part of the sound to sound like mini-mono or to take coloration of that specific speaker.

Indeed I did
Thanks for your clarity as usual.

When you consider those two approaches, it makes sense of the moment when Trifield snaps into place and the sound seems to comes from the whole of the front of the room. You can still localise instruments/players/vocals etc in space but they do not come from the drivers anywhere near as much as other presets.

FWIW...when I got my 8k's I ditched Trifield for quite a while as the 5kc didn't seem to hold up too well against them. However, recently I spent an afternoon recalibrating and playing with things (not easy when the G68 is in another room). As is often said, when Trifield is tweaked just right, it ain't half bad !!!

lwang, thanks for that very simple and informative explanation. Extending the thoughts in this thread, what would be the "Trifield equivalent" for multichannel sources? What Meridian preset would you use for DD and DTS 5.1 sources, for instance?

I use DPL IIx for the sources- I believe I either read somewhere or someone from Meridian directly told me this is the way to go with 7 channels. The results are great.

best regards,
Jerry

Me too (DPL IIx)- Also great with 5.x sources and encodes are carried in 2 channels...

ken

Me too! (for all multi-channel movie sources). For DVD music, I'll try discrete, PLIIx movie and PLIIx music and go with what my ears tell me.

Back on to Trifield, I'll tell you what... My set-up (three tweeter aligned horizontally oriented DSP33s with a little L and R toe-in) is sounding simply superb at the moment. Listening tonight, it's clear that lwang's comment about removal of speaker localization is spot on!

To me DPLIIx seams to make more of the soundstage that really isn't there in the original recording. I stick with Cinema for movies using 7.1 and Music or Trifield for two channel music set to 5.1. I don't care for side speakers when listening to music. I use Music mode more than Trifield. Yes Trifield can sound more pin point with imaging but I just feel it isn't the original as it was recorded. Music mode adds the center and very little ambient from behind that sounds just right to my ears.

Ron

For multi channel DVD Video sources I find "Cinema" to do the best job. My Meridian deal told me that DSP mode was the highest upconversion that Meridian offered. I had been using PLXII for the first five months or so when watching 5.1 material and the conversion to Cinema produces a subjective improvement over PLXII. For multichannel DVD Audio sources I use "Discrete."

Aginglawyer

Viruskiller,

For multichannel sources, you would probably go with whatever the original format it is meant for since. The preferred method would obviously to pass through the 5.1 discrete channel format through a B-format recovery system, which would then be passed through a Ambisonic processing system which would allow unlimited channel capability. This has been proposed by ARA as a Ambisonic G+2 format, which would be compatible with standard 5.1 system, 2ch system or any system with the B-format recovery. If it is for pan-potted front/side/rear mix, instead of recovering B-format information, they could easily apply Trifield 360 deg around. I am not sure why Meridian is not providing this feature especially if they are the people pushing this format.

Ronomy,

Trifield might make a more of a soundstage than the original recording is exactly its purpose. Conventional music surround more or less converts a recording that's pan-potted between the L&R channel to be pan-potted between L-C and C-R (most seem to emphasize extracting L-R type of ambiance and try to place it somewhere in the rear to give you the impression of reverb). But that's not how our brain hear sounds.

A viola coming from the right side of the stage has almost the same loudness to our left and right ear, but due to it being off axis from center, the sound arrives at our ear at different times. In a multi-mic recording playback, the way a viola is presented as stage right is by having the right loudspeaker play louder than the left. Our brain combines the sound together to tell us that more of sound is coming from the right, but the the spatial localization part of our brain hears sound coming from the left speaker and right speaker, confusing that part the brain causing us to think the sound is coming from nowhere. So the original soundstage presentation is false already.

The way Trifield works, it tries to restore that part of the spatial localization that's missing in those flat 2ch recordings. In doing so, it allows our ear to localize sounds in all the ways it knows how to, so one method does not contradict with the other, allowing us to image instruments more naturally. (It also does the 2 to 3 ch conversion, but as described before, as a 3 speaker unison, instead of L-C and C-R).