Center channel signal is lame! Manufacturers listen up

Run the processor in the phantom mode without a center channel speaker, if you are concerned about the sound field collapsing into the center channel. This solution can work well for DPL (4:2:4), but works poorly (IMHO) with discrete formats that do not share this tendency. BTW, the manufacturers are only following the surround formats created by companies like Dolby and DTS. The dicrete center signal is monaural, but it is not the only speaker in the front channel array. There are a few on this site that are fans of a 5 speaker array in the front of the room (left, left center, hard center, right center, right) that appears to be available in one of the commercial formats (I think SDDS).


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Don O

If it isn't in the D-ILA FAQ let me know


[This message has been edited by Don O'Brien (edited 11-27-2000).]

ditto the phantom thing!


I tried this the other day and now I am not so sure I need a center channel.


So many people complain about how difficult it is to buy a center channel that integrates correctly. I have read a couple of threads that say it is almost impossible but now I think the idea is use PHNTM!


I think I'll be keeping my center although I'm sure that Aerial center channel could ease much of the pain http://www.avsforum.com/ubb/smile.gif !


whats that model again???


I have a GREAT center channel I would be willing to sell E-mail me for details! J/K It's the pinnacle classic gold center channel the one thats like 3' wide. I do have one thing going for me and thats having the same tweeters all around.

This would make the center channel sound seem much more "locked into the center" and much less spatially varied than it should be.


Do you think this might be what you are experiencing?



My problem isn't with being "spacially varied" in fact my "sweet spot" is just fine. I just think it lacks dynamics and depth. If I could slightly delay the signal to one of my center speakers then I could fake the depth thing. In theory taking my 2 dimensional center channel sound and making it 3d. Any further input would be appreciated


As far as the sound meter goes I should do this for sure. I have in fact turned up my center channel so I can hear dialog without having my room explode during crash and burn scenes, or just entry orchastration.

Anyone have comments on this?



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Tryg Hoff

Quote:
I have a CC-200 I've used the CC-270?(monitor series), and even one Titan sounds better. much more detail in the high end. Even for the crappy center signal. 2 Titans sounds even better than one. No loss of detail and more spread out. The way I have them wired(a secret of course) makes them essentially a 6ohm center with the Titan drivers(which I'm in love with) I have demoed 4 center speakers. My current setup is the best.


My beef, is with the signal. I'm laughing... cause now you guys are gonna be focasing on this too during a movie. It's gonna piss you off:- )


How do you do this dynamic range compression thing on the Denon?



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Tryg Hoff

I am at a loss in understanding the problem you are experiencing. I believe it is because of the fidelity of the center channel and not that you are critical of single channel being mono. We are pleased that you like your setup, but placing two center channels in close proximity on a horizontal axis is going to change your perception of the original signal. Placing speakers close to a boundary (floor) can also change the perceptual frequency character of the speaker.

Would it be possible for you to give us specific passages in a movie or 2 that you find the center channel signal is lame. Could you expand on what is lame about the center channel sound you are experiencing. Are your left and right speaker level matched to the center? Are you driving both speakers with a single channel of amplification? What have you place in the speaker lines signal path to achieve a 6 ohm impedance.



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Don O

If it isn't in the D-ILA FAQ let me know


[This message has been edited by Don O'Brien (edited 11-29-2000).]

Quote:
BTW what is Phantom mode? will it help me? and can I do it?




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Tryg Hoff

Quote:
Engineers and producers go to great lengths (ADR in sound proof booths)to create the clear mono dialog track in films. A single person speaking is a mono source.

Try a simple experiment;

Listen to a mono recording through just one speaker.

That will give you the most accurate reproduction of the signal.

Play it back over two speakers and the signal will be altered (by an acoustical phenomenon known as comb filtering which will alter the frequency response of the signal).

You may find you like the altered version more, but be aware it is less accurate.

Playing the center channel over two speakers will have the same effect.

Adding a delay between the two speaker will exacerbate this.

You might like it. But likely with many soundtracks you will lose some intelligibility.



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Buzz Goddard
www.tagmclarenaudio.com

Wow. Interesting discussion. Sorry to be getting in late on this one. I've skimmed all the previous, but forgive me if some of my thoughts have already been said.


There does seem to be some cyclic redundancy to the discussion. Tryg, I appreciate what you are expressing but I earnestly urge you to focus not on the sound system per-se, but on the mixing challenges faced by motion picture soundtrack artists. 3 speakers across the front is enough for spacious audio, but let me hazard an explanation on why what you are experiencing is less than that.


I have a stereo recording of Miles Davis who's music I really like, but who's mix I detest. The sound engineer elected to put the bass guitar exclusively in the left speaker and the drums exclusively in the right (all other instruments image in the center). This makes the two instruments in question sound less lifelike than if they imaged even as half left and right respectively. From all your posts above, I suspect that a similar lack of liveliness is what you dislike about dialogue from a single speaker.


Does that mean all Hollywood sound engineers are mixing 'bad' soundtracks? Heck no! Remember (and this is key) they are faced with the challenge of mixing a soundtrack that will match the on-screen image AND do so regardless of where a person is sitting (relative to center). So while it would be possible to mix dialogue as a phantom center image from the left and right speakers, it just doesn't 'work' for anyone seated even slightly off center.


No matter how many speakers we put in the front soundstage, the goal of coordinating sound to visual cues will always result in sound from just one speaker, IF we want to accommodate people off center. Sony's cinema-only sound system SDDS (of which I am personally a fan) can have 5 screen channels. Even still, dialogue will often come from one of the five speakers not only to 'lock' the dialogue to the exact left-to-right position of the visual that is producing the sound, but also to ensure that the same sound (in terms of tonality) is heard by all. If they were to mix a line of dialogue as a phantom image between center and left (for example), people off to the right will get the comb filter effect which may affect intelligibility. This is one of the prime reasons to use 5 screen channels: more creative possibilities for horizontal positioning of sound with less phantom imaging. As such, you get pin-point and consistent sound, no matter where you are seated in the horizontal plane. For this and many other reasons, 8 channel SDDS (when used correctly) is really something special.


Enough about that...


The posts about the comb filtering artifact of two speakers used for the same channel are not without merit: it is a very real problem. To answer question 1 of your above post, most center speakers based on the ubiquitous mid-tweet-mid design do not eliminate the comb filtering effect (in fact, they exemplify it) BUT, the closer the drivers are sandwiched together, the farther off center you have to be before it becomes an real issue.


Even so, several upper end receivers have two speaker outputs for the center channel. They do this for people who have HUGE screens and can't put the speaker behind it. If the screen is big enough, a center speaker above or below may be so far away from the visual cue, that it strikes our brains as 'wrong'. In that situation it MAY be preferable to put a center above AND below the screen so that the sound images in the center of the screen for most every one in the room, without too much in the way of artifacts (unless you have a balcony http://www.avsforum.com/ubb/smile.gif )


Anyway, based on what you've said, I'd like to know if you have auditioned the Mirage OM-C2 center speaker. I reviewed it sometime ago and was substantially impressed (it is a really boss speaker). I mention it here because I think it's very unique and exclusive Omni-polar design will give you the sort of sound you crave in a single speaker.


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Brian Florian

Editor, Canada


Secrets of Home Theater and High Fidelity http://www.hometheaterhifi.com \\


[This message has been edited by Brian Florian (edited 12-01-2000).]

Brian,


Thanks for your input!!!


I was about to lose hope that nobody knew what I was thinking or talking about. I will try to move one of my center speakers above my screen and see if this does anything. No, I have not tried that specific center channel speaker(Mirage).


How does 5.1, DD integrate with this SDDS commercial standard. Meaning, is it worthy of home use? Will my DVD or 5.1 signal be translated correctly or do you need to play commercial type sources to benefit?

If so, I'll be looking for this equipment for the future (cause my screen isn't getting any smaller).




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Tryg Hoff

SDDS (Sony Dynamic Digital Sound) is a completely different multichannel encoding system, just as Dolby Digital and DTS are different. A single film print can have all three soundtrack on it: DD goes between the sprocket holes, DTS slips in a thin time-code next to the picture (the actual audio is on a separate disc) and SDDS resides on the two outer edges of the film strip.


It is a true discreet 8 channel format, with 5 screen channels, two surrounds, and an LFE track. Not all SDDS releases have 8 channels. The majority have 6 channel just like DD and DTS due to higher production cost. Also, not all SDDS equipped cinemas have 5 screen channels (in those cinemas, 8 channel SDDS soundtracks get downmixed to 6).


SDDS is currently a 'cinema-only' sound format for mainly two reasons: They want to keep the cinema 'special', offering something (8 discreet channels) that not even the finest home theater can. Also, very very few are the home theaters that can take advantage of 5 screen channels. I mean, you need a REALLY wide screen before the benefits would be worth it. The system was really designed around bringing back some of the grandeur from the great 70mm movie houses of the 60s.


Please remember it is still subject to the same mixing principals as DD and DTS. IE: Dialogue will still often come from one speaker, so it's not addressing your concern there. More screen speakers represents more possibilities for point sources (and more pan permutations), not necessarily more phantom image possibilities.


Although Sony has absolutely no plan to bring SDDS home at this time, they did manage to 'slip in' an SDDS flag into the DVD spec. There isn't any consumer hardware that would know what to do with it but I suppose one could say the possibility exists...


Some examples of recently released films with 8 channel SDDS soundtracks include:

"Erin Brockovich,"

"U-571,"

"The Patriot,"

"Hollow Man,"

"Vertical Limit,"

"Charlie's Angels,"


But if you want to hear the 8 channel mix, you'll have to go to a cinema so equipped http://www.avsforum.com/ubb/smile.gif .


Cheers,


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Brian Florian

Editor, Canada


Secrets of Home Theater and High Fidelity http://www.hometheaterhifi.com


[This message has been edited by Brian Florian (edited 12-01-2000).]

Quote:
Buzz,


I like to hear thoughts on this stuff. Please tell me how:


1. Most all center channel speakers have two main drivers. How do they eliminate this "comb filtering"?


2. Accuracy and Intelligability? I am a very acute listener. Who else would test 4 center channel speakers, then seek other means to achieve audible nirvana. I don't want to be insulting here, but If it sounds better, I can promise you it is more accurate and intelligable. Sound is and always will be, subjective.


BTW the secret to my center channel set up is the same way most all center channels are built. I just unhooked one of the tweeters and hooked that speaker in parrallel. Rocket science, no. Does it reproduce what it's receiving well/ Yes. MONO, MONO, MONO.


Thank god we moved on to stereo back when we did. Even if people still think mono captures the human voice "more" accurately, I will never agree with this. Mostly because everything I've heard recorded with stereo mics sounds more dynamic, colorful and rich.


I'm just asking for Maufacturers to do this to the center channel. Just give me a Pro logic center and I'll be happy(it doesn't have to be dicrete).




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Tryg Hoff