are computer techies just ignorant of a/v? (1 Viewer)

[ChrisWiggles]

Personally, I definitely disagree.

5.1 cannot complete a convincing rear-soundstage. 5.1 can have good envelopment with side dipoles, but especially with direct-radiating speakers, rear-ward effects simply are not convincing in comparison to a 7.1 or more array.

I am actually pretty surprised that so many people here think that 5.1 can do this as convincingly as a 7.1 array. Sure, there are reasons of cost why going 5.1 may yield an overall better system, however given the choice between a 5.1 system, and the equivalent system with the addition of two rear speakers of matching quality, there is absolutely no doubt that the latter choice is preferred.

This preference also has nothing to do with whether the room is small or a large auditorium. The limitations of properly placed side surround speakers in a 5.1 simply cannot create cohesive rear imaging or panning behind you regardless of the room size.

 

[LanceJ]

If this means the rear channels in a 5.1 rig literally being placed to the side of the listening position, it's easy to understand why there is no chance - of course - of proper rear imaging or front-to-rear panning. Why Dolby keeps advocating that illogical speaker placement is beyond me.

The rear channels in *my* 5.1 system are behind me (at ear level) by almost four feet.....because I like to be truly s u r r o u n d e d by my movies'/musics' s u r r o u n d mixes.

 

[ChrisWiggles]

Side surround placement is necessary or you lose tha ability to maintain a good consistent imaging between the main speakers and the surrounds.

You can get far superior rearimaging, similar to that of a 7.1 system, by incorrectly placing the surround speakers farther behind you, but your soundstage between the rear and front collapses and has a large gap in it. This is why 4.0 systems are not at all sufficient for cohesive surround imaging. Doing this to gain rearward imaging is a bad tradeoff because the front-to surround soundstage is far more important in a cohesive experience than imaging behind you.

Properly placed surrounds will be located to the sides, and as such have difficulty imaging behind you. You can have one or the other in a 5.1 system (with proper side placement STRONGLY recommended) but you simply cannot have both. This is why 7.1 arrays can complete that rearward soundstage and improve that missing rear imaging that 5.1 just cannot pull off as well when properly setup.

 

[Wayne A. Pflughaupt]

I’ve never had a problem with the front-to-rear sounstage. Apparently neither has Lance, or the other posters on this thread. I have my surrounds behind me, too. Don’t know what Lance is using, but I have direct radiators with wide dispersion tweeters a couple of feet behind me and several feet to the side (which gives plenty of distance for proper dispersion). The way it ends up is that the seating is pretty much equidistant from all speakers. Maybe that’s what makes a difference.

There’s no logical reason why the front/rear soundstage would collapse without a side speaker, as long as the rear speakers are the right kind and set up correctly. If that were the case, the front left and right soundstage would have the same problem, and they would have added a center channel to stereo music decades ago.

Perhaps the 5.1 systems you’ve been familiar with have been less than optimal?

That said, I can see where 6.1 or 7.1 would have advantages in some situations.

Regards,
Wayne A. Pflughaupt

 

[ChrisWiggles]

5.1 has never been sufficient to have a seamless soundstage all the way around you. I believe this has always been fairly well-understood in the literature. The angle spread by the surrounds if they are behind you is far greater than that of a two channel system. For two channel stereo, you usually have an equilateral triangle or narrower angle to maintain imaging, or the cohesion begins to fall apart across the front.

With surrounds correctly placed beside and *slightly* to your rear as per dolby recommendations, you can maintain good imaging between the surrounds and the front L/R. Placing them to the rear (where the SB speakers would be in a 7.1 system) drastically cripples this capability, and you have a front and a rear soundstage, but nothing in between. Panning to the side, which is far more significant and important than imaging behind you, is significantly degraded.

I've heard many systems in both 5.1 and 7.1 implementations using both Dolby and ITU arrangements, and there simply is no doubt that 7.1 allows for significant improvement in the rearward soundstage that 5.1 does not pull off convincingly.

If you are going to do a 5.1 array, do it correctly, and don't try to force the full performance of a 7.1 array to the rear. The cohesion from the fronts to the sides is far more important and much more often utilized than rearward imaging and panning.

If you place the sides too far behind you, you're looking at an angle probably about 90 degrees. Nobody runs a stereo setup with this large an angle in the front, because of obvious collapse of imaging between the two speakers.

In my opinion, the next logical addition for speakers beyond 7.1 at least in the horizontal plane, is clearly wide L/R fronts between the SL/SR and the L/R to better anchor imaging from the front to the sides/rear better. 5.1 with properly placed speakers is really at the edge of holding that cohesion together. It does it well, but not as well as it could ideally, and in many rooms where some compromises have to be made, especially longer rooms, this can become a more significant obstacle than it would be in more idealized spaces.

 

[Dave Moritz]

That has not been my exsperience, as many of the tech folks I know. Do not know much about audio/video and most of them do not have home theater systems. I realize that others here have a much different exsperience than I have. For example one tech friend just about a month ago got his first home theater system (HTiB Onkyo reciever with 7.1 speaker system). Another friend only has a 5.1 Klipsch pc speaker system only on his pc. Two other tech friends only have two channel pc speakers on there pc. There are about 8 people I know that do not even know what SACD is and they do not have surround systems on there pc or a home theater system.

 

[Wayne A. Pflughaupt]

I think I get your point, that as long as the rears in a 5.1 are properly located, it’ll work fine and there won’t be a front-to-rear soundstage problem. Put them too far behind you, especially where they’re supposed to be for the rears in a 7.1 (directly behind and closer together than the fronts) and you may have a problem. I can see where that could happen.

Regards,
Wayne A. Pflughaupt

 

[LanceJ]

Wayne: I have direct radiators (Pioneer bookshelves with 8" woofers). They are @four feet to the rear and to the sides of me, using the parameters set forth in that Grammy.com paper.

When we are watching I, Robot, Gattaca and the numerous other films where there are characters walking/talking in large open spaces, the feeling of being in those scenes borders on the creepy-ish: the "big sound" i.e. reverberant quality me and every other person seated with me hears is unmistakable & is all around us. It is definitely not just confined to the front soundstage and the rear soundstage. When planes/ships fly overhead they move smoothly from one end of the room to the other - there is no "jumping" effect.

I can see where if someone had their system located in a very long room (where the monitor & rears were placed at the short sides of the rectangle), side surrounds might be helpful. But if they asked me where to place the rears for best effect and they were not overly concerned with decorating issues, I would tell them place them on stands behind/to the sides within a few feet of their listening position. And they can save hundreds, or thousands, of dollars by not buying another pair of speakers & also avoid the hassle of even more wires to run.

Also, in that Widescreen Review article, most of the panelists said they don't think full-blown side imaging is physically possible - when a person is not facing in that specific direction - given the way human hearing system operates. Even the WSR reveiwer (the guy heavily advocating 7 & 8 channels) agreed. And IIRC only one panelist said he even tries to create a sidewall image.

 

[LanceJ]

And: this is just theory on my part but I'm not so sure a movie's soundtrack is going to feature a heavily-detailed rear soundstage that would require 100% accurate reproduction. That's because the visual image is in front of the audience, so I think any truly important sonic events that require pinpoint localization would be placed there (this is why I personally don't like using dipolar designs for the front channels for HT-only use i.e. they are too "blurry" sounding).

 

[Wayne A. Pflughaupt]

Lance,

In the place we lived until about a year ago, my rears were set up much like you described – probably 4 ft behind, and another 4-6 ft to the sides. I always liked the way you felt “enveloped” in the sound, compared to systems I’d heard in home theater stores that had them directly to the side and perhaps just barely behind the seating. Those to me sounded like the soundfield was all out front, and brick-walled right where you were sitting. IOW, everything to the sides and front, but not “around” you.

That’s why I don’t like di’s or bi’s for the rears as well. If they do pinpoint something in the rear channels, I want to know it.

Regards,
Wayne A. Pflughaupt

 

[ChrisWiggles]

I'm surprised you think this. Try placing your front speakers in a similar position as dictated by dolby 5.1 placement, that is to the side, firing across at each other, one to two feet in front of your listening position. There is just no way that this kind of placement can create a convincing phantom center image between an angle that large. 5.1 systems were never designed to be able to create strong rear-panning effects, and they can't really do it. That's why EX/ES processing and 7.1 arrays are deployed to add rearward capability that just can't really be pulled off well at all in a 5.1 system.

If you follow the ITU type recommendation with surrounds not beside you but in a circle and further to the rear as recommended for music, the rear angle is small enough that rearward imaging is similar to that of a 7.1 system, but I personally don't like this kind of placement because the imaging between the rear and the front is lost because that angle is too large. This is very distracting because now you have two disconnected soundstages, which is why I don't really like that kind of placement. This problem is easily solved with a 7.1 array that can maintain far better imaging between the sides and the front, and then also around to the rear which simply is not possible with side-located surrounds in a 5.1 array.

 

[ChrisWiggles]

For movie soundtracks, this is usually the case. Most of the stuff going on is happening across the front. However, where rear-effects are more than just ambience while there may not be nearly as much detailed "imaging" in a sense, the capability is important to maintain because what you will get a lot of especially in dynamic mixes, is panning effects. Pans will really fall apart and be distracting if the imaging capability is lost between speakers. That isn't to say that arrays and dipoles that produce diffuse sounds and can't really do pinpoint imaging are detrimental. However, there does need to be enough cohesion to produce SOME kind of image, however diffuse, to allow for panning effects.

Otherwise, if you have a sound panning to the rear left for instance, you'll hear it in the front, then it will sort of vanish, and the jump and reappear towards the rear left. In a 5.1 system with side-placed rears the same thing will occur if you attempt to pan across the rear. As the image tries to maintain itself across the rear, it simply can't and will jump from SR to SL very unrealistically. This capbility is greatly enhanced with a 7.1 array. Certainly, one can argue that this capability isn't a big deal (and in a lot of film mixes it's not), but it certainly is a capbility that some mixes do take advantage of. If you want that effect, you have to move to a 7.1 array.

 

[Wayne A. Pflughaupt]

I can’t honestly say I’ve experienced what you’re talking about here, Chris, but (as previously noted) I also haven’t been aware of it to have noticed.

It’s an easy enough situation to verify, so I decided to put it to the test. I connected my rears to the main channels and put on a CD I’m familiar with that has lots of panning back and forth. And yes, I could tell that the movement wasn’t nearly as smooth as it is in the front speakers.

I don’t necessarily agree that the problem is speaker placement so much as it is a differences in the way we hear and/or mentally process front vs. rear sounds. After all, if the ear heard sounds from the rear the way it does from the front, we probably wouldn’t be able to tell which way they were coming from.

Nevertheless, I can see where a center channel could help rear panning. However, I expect with movies it’s not really as distracting as you present it to be, especially with all channels going at once, and since your primary focus is on the screen. So I’m still not convinced that it’s worth the expense, hassle and added visual distraction of yet another speaker or (even worse) two. Maybe in a dedicated room, but not in my living room!

Regards,
Wayne A. Pflughaupt

 

[ChrisWiggles]

Certainly, we have decreased ability to image things behind us, but even still, with side-placed surrounds, the strong sense of "that came from BEHIND me" isn't nearly as convincing as it is when you actually have speakers back there.

It's rare especially, but if you have sounds that circle around the room, you can hear where a 5.1 system will start to suffer to the rear. I have a concert DVD with a somewhat strange DTS mix that has a tabla drum doing circles (it's actually a little bit annoying) around the room that illustrates this.

Anyway, it's not all together a huge deal, but in my mind and experience 7.1 definitely does have some increased capabilities over a 5.1 array.

There is also the last little note that I use EX/ES processing on every 5.1 title, and I've never run into a title that has mono-rears that EX/ES would dump to the back. That would certainly be undesireable, and it is something to be aware of. And if someone is ONLY using EX/ES processing on titles actually flagged as such, then for the vast majority of films the rear speakers and capability is completely unused. However, I think that most people use EX/ES or PLIIx on everything except for perhaps that odd theoretical mix with mono rears.

 

[LanceJ]

I haven't done a scientific survey or anything on this, but AFAIK there are lots of movies that pre-date Dolby Digital/DTS that either are straight stereo or were encoded using only Dolby Surround. For example, I own two dvds that have a stereo track with a dedicated mono surround channel (3.0 format?), Uncle Buck and Starman. My receiver's channel indicator array looks like this: [L] [R] and ; indicates the mono surround track. I guess the studio doesn't trust everyone's Dolby decoder to properly decode a Dolby Surround matrixed signal. Actually, most of my dvds are either straight stereo or have 2.0 channels but are actually recorded mono.

And I have about 70 VHS tapes, which of course are only 2.0 channels (stereo or Dolby surround). About half these I haven't any plans to buy in dvd form since they are not a big priority but I still like them enough to keep them around for occasional viewing. Another large portion of my collection are MST3K epsiodes, including quite a few 6 hour tapes, and a bunch of sports-related recordings and old sci-fi B movies.

BTW: my four year old receiver doesn't include Dolby Pro-Logic II, DTS-Neo, etc. So someone may want to enlighten me on the following issue, but I've never read where any of these enhancement systems generates right-rear to left-rear panning effects (how would they "know" when and how fast to do so based only on a mono matrixed signal i.e. a Dolby Surround encoded track? Or especially, what about a straight stereo track?).

I don't have that large a dvd collection compared to many here, but as someone who watches many older and non-action movies (including many in black and white - go TCM Channel!! ), in the Big Picture (haha) I have a feeling the number of discrete 5.1 channel soundtracks out there is enormously outweighed by the non-discrete variety.

 

[ChrisWiggles]

These aren't 3.0 tracks, they are just stereo tracks flagged as Pro-logic encoded. They are 2.0. This is very different than 5.1 with mono rear backs which your receiver would identify as 5.1.

 

[Wayne A. Pflughaupt]

Thanks for bringing all this to our attention, Chris. It’s certainly good information to know, even if I was a bit slow to grasp what you were talking about.

Regards,
Wayne A. Pflughaupt

 

[ChrisWiggles]

Love to do it! I'm just glad it didn't turn into a 5.1 versus 7.1 war or something, I'm usually bad with getting sucked into arguments like that which is beside the point entirely.

I think that for people that currently have a 5.1 system without an easy upgrade path to 7.1, don't worry about it. The cost of a new receiver and speakers is pretty huge compared to the improvement which is nice, but it is fairly subtle. It isn't even REMOTELY in the same ballpark as the difference between PL and DD for instance.

But I think for people building systems now, or upgrading receivers, pretty much everything nowadays has 7.1 capabilities, so all you'd have to do is add another pair of speakers as budget allows, which need not be immediate.

I am fairly excited about discrete 7.1 possibilities with upcoming DD/DTS formats on HD-DVD and BD, but I'm a lot more excited about hi-res lossless coding and generally higher bitrates.

Oh yeah, and are computer techies ignorant of A/V? Who knows, but the one thing I know is that *this* A/V techie is pretty ignorant when it comes to computers!

 

[Dave Moritz]

I currently have a 5.1 system and have heard some awsume 5.1 and 6.1 systems at CES. Two of the best systems I have heard to date where 6.1 systems. Both at CES, one demonstration was put on by Faroudja and the other was by DTS. Oh the demonstration put on by McIntosh was really good as well.

Anyway if the room is set up right and the system is properly calibrated. I could see a 5.1 system outdoing a 7.1 system. I would like to have a 7.1 system but since the room is not big enough for a 7.1 system my current 5.1 system is more than enough. The plans are to upgrade to a 1080p projector, buy a Blu-ray HD player and upgrade my Yamaha RX-V995 to a Denon 7.1 reciever.

 

[JediFonger]

that's right, i don't think one can even buy 5.1 a/v receivers for all the new models coming out. they're all 7.1 by default.