Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems Phantom Centre

Is there anyone who tried the phantom centre in the Meridian setup.

As many of the people mentioned that setting the centre channel at the right height is difficult, can we just ignore it? Not too many people are lucky to have the Stewart THX certified sound-screen anyway.

The sound stage seems more seamless when phantom mode is used on my non-Meridian gear but I cannot control the dialogue volume which usually comes from the centre.

I would be delighted to hear if Meridian can still control the centre channel volume when it's phantom just by distributing it to FR and FL speakers.

May be some of you know that some music company may come up with 6.0 DVD-A rather than 5.1 with 2 front 2 side and 2 rear (roughly like a hexagon), the centre channel might just give you more trouble than to give you much better sound with a screen in the centre. Any opinion or any live experience to share?

Rgds,
Dennis

I tried it for a while thinking it was for only folks not in the sweet spot. Well it's more than that. I just felt like the voices were not coming from the TV.

What's this phantom centre anyway ? I'm clueless...

I created a phantom centre type (no centre) on my 568 that I can switch to when I feel the need. You can still adjust the centre level in this mode. I find the phantom mode does not work if you sit outside the sweet spot and even when in the sweet spot, something just seems to be missing on movies, Music is a very close call which, I set the 568 to no sub for Music and set the c/o to 120hz between the centre/surrounds and the mains which handle all the bass, they are 3 way tower, the centre has the same tweeter and mid/woofers as the mains and the 120hz c/o is close to the mains c/o from the mid to woofers of 240hz. For DD/DTS/logic I set LFE sub and the c/o to 50hz to get more punch from the centre for movies. Some DTS CD's are mixed without a centre. My centre is located below my TV about 30" high which puts it about 6" below my mains. This postition works the best for me, I have tried it above the TV with a lower stand which put it about 12" above the mains.

[This message has been edited by mic (edited 02-06-2001).]

[This message has been edited by mic (edited 02-06-2001).]

[This message has been edited by mic (edited 02-06-2001).]

"Not too many people are lucky to have the Stewart THX certified sound-screen anyway."

You may want to read the thread here called "Projection". Stacey Spears and myself feel that the loss of audio quality using an 'acoustically transparent screen' is not worth the questionable improvement in psychoacoustics, especially when three floor standing main speakers are used across the front so that the midrange and tweeter are within an inch or so of the image. The natural dispersion pattern of most good speakers makes the sound appear as though it is coming from the image, even with a viweing distance of only 10-11 feet in my case and the front 3 speakers out in the room for optimal acoustical placement.

When you consider the overall negative impact on audio/video, a perforated screen is not the way to go IMO.

I have to admit I would rather use a phantom center using two excellent speaker for mains than throw in a compromised center channel. In other words, if I could not use the same center channel as the front L, R, I would rather go phantom. Scratch that... I just woldn't settle for anything other than having the same exact speakers across the front.

[This message has been edited by Health Nut (edited 02-06-2001).]

Dennis,
Health Nut is correct that the best for Video is a motorized "non" perf screen as many including me are using. The point I tried to make was that sometimes reference speakers are build quite big and they are recommended to have their "accoustic center" at the listener's ear level (probably somewhere between the tweeter and the midband-woofer). Good dispersion patters help of course to go for that little amount of tolerance.

Now my dream speakers would raise the screeen-beginning height from the bottom dramatically, if I would start with the screen right above them. Good that I cannot afford them .

Some people, including me, feel very uncomfortable when one has to look up too much. It is more relaxing to look right into the picture with at least 1/3 of it below eye level. I would probably like it the most to be able to look right into the middle of the picture.

I would only choose a perf screen, if I could build that double screen system I mentioned, especially to decrease light scatter and sound reflections, I mentioned that before too.

Concerning your phantom center image question. Meridian Digital speakers will render a much more precise phantom image. Many regular high end systems suffer, they image just to big or unclear to work with the picture/mouth movements, due to problems in phase and frequency responce linearity. Room problems play a role here as well.

Of course in a black room, where you cannot see your speakers (mine is quite black), the psycho accoustic will fool you, but not everybody is fortunate to have a black room .

Andreas

[This message has been edited by Andreas (edited 02-06-2001).]

Andreas and Health Nut, am I correct in saying that given that I have a center speaker below the screen, with good dispersion, the further that I move back from the screen the better is the psycho accoustic effect?

Just want to make sure I understand this.

Raymond

Hi Raymond,

I was talking about a black room masking black speakers, not about distance.

Great distances can even harm your center sound quality depending on the room. First reflections from the direct next walls and the ceiling will reach you "early" and high reverb due to the listening distance can cause serious problems, well again, depending on the room.

Most people simply cannot hang an accoustic absorber on their ceiling, so they have naked ceilings and in the typical European flat they are even quite low . Reflections are the reason why we have the THX approach, well the D'Apolito (is that spelled right ?) center speaker design, to minimize reflections from the ceiling e.g. Besides the fact that a certain specified directivity helps in rooms with accoustic problems, most of these "special" speaker simply suck in terms of high end fidelity.

It all comes down to buy 3 equal front speakers (or 7 for 7.1) and buying flowers on a regular basis for your wife, to work her around to get permission to install that ceiling and wall treatment .

Regards,
Andreas

Andreas,

Thanks for the reply. I have a typical European flat low (2.4m) ceiling and the majority of the flat is white.

To be more specific, my front speakers are 3 MK5000 THX. I am going to buy a new GrayHawk electric rollup screen, but I am not sure if the micrcoperf is the best way to go. From what I have read, it seems that it is not. I have a totally dark room and will be sitting about 4.5m back.

Conclusion-HELP!

Regards,
Raymond

Thanks for all your reply. However if a 2 channel system can fool so many die-hard audio fans that the orchestra is playing and someone is playing the instrument in between and outside the speakers and even out of the room in some case why can't it be done in home-theater?
It seems like the decoder is not doing the right thing in the phantom centre case. I agree that without the centre, it seems something missing, however adding a centre cannot solve the problem, usually the dialogue is louder but most of the case, I don't feel the sound is coming from the mouth of the actor.

I have tried to raise my screen higher and raise the level of the centre channel - just a little bit because it's not easy in a CRT setting. The sound stage seems better but then the picture is getting too high that you have to look up and the complete sound stage is underneath the picture.

Any solution from the acoustic experts?

I have also found an interesting product from Goldmund that they can distribute the centre channel to two FL & FR by a mono feed. They need only 4 speakers for 6 channels. (Please look at the site as it's hard to describe in words) Can we simulate this by putting two more speakers identical to the front channel with mono settings on left and right of the screen at the right height to replace the centre channel on top or bottom of the screen?

Any brave(and rich) guy in this forum wants to try this as you need one more amp and one more speaker just for the test?

-Dennis

[This message has been edited by Dennis Ho (edited 02-06-2001).]

Dennnis,

as you admitted you don't have a Meridian processor yet, so there is your problem .

Although 2 channels are not perfect for film soundtrack reproduction, Meridian processors offer for each mode (AC-3, THX, DTS) "lipsync" delay settings, to match the speakers to the mouth movements.

In your case you could set the decoder to no center and still delay all speakers to match the mouth movements.

However, since you're not using a center, your two "mains" will probably image not as precise as if the voices would come directly out of a center channel from on of the "dicreet" formats (AC-3/dts).

So the lipsync parameter would be a little harder to set by ear.

If you feel unconfortable to go for Meridian yet, try to shift your center speaker forth and back under the screen to simulate the necessary lipsync delay. Then of course you would influence the delay of the center to the other speakers as well !!!, so trust me, it's time to go for that long dreamed of 568 or 861 .

Raymond,

of course the micro perf is not the best way to go. If you want to maximize your video potential then go for a Studiotek 130 non-perforated. If you feel you have the possibilities for experiments and that you could sacrify a bit for movies then try a microperf solution. The biggest benefit would be that one could hang the screen much lower and that's about it. Center speaker placement is a pain in the "neck" (setting it up and looking up).

BTW: my ceiling is 2,5 meters, but I'm sitting only 2,7 meters from my center away. As you can calculate the distance is in you case quite high. So without accoustic treatment you will have to live with sides- and the ceiling-reflections to a more severe extent than I have to.

So, it's probably good that you bought the M+K "THX" speakers, since you probably cannot treat your room ?.

Andreas

[This message has been edited by Andreas (edited 02-07-2001).]