Why from 5.1 to 6.1 to 7.1 - Where's 8.1? (1 Viewer)

[Lin Park]

I understand going from 5.1 to 6.1 by adding a rear center, but why was the rear center abandoned when the manufacturers went to 7.1? Wouldn't it have made more sense to go with 8.1 by adding two side speakers to the 6.1 configuration or were they simply trying to keep the upgrade paths coming?

I know the rear center was a matrixed configuration but I'm guessing that in another few months we'll be seeing these 8.1 upgrades coming out. What does everyone else think about this?

Lin

 

[Michael Reuben]

Seven-speaker setups predate the arrival of Dolby Digital EX and DTS-ES by several years. (The magic word is "Lexicon".) Most of the current setups commonly called "7.1" grow out of THX's recommendation for Surround EX that the rear center be sent through two separate speakers. Receiver manufacturers like to call it "7.1", because they think in terms of channels of amplification, but it's not really a meaningful (or accurate) notation.

Only with Logic7 is there different information sent to the left and right rear back speakers, courtesy of fancy DSP. Otherwise, the configurations labeled 7.1 are really no more than 6.1 at best.

M.

 

[Phil*K]

Lin,

Actually there is 8.1 already, but you have to buy Yamaha. The RX-V1, RX-Z!, and RX-V3300 all have two front effects speakers In addition to their normal 6.1 setup.

Phil

 

[Kevin C Brown]

There is a psycho-acoustical effect called "reversal". When the human brain hears a sound directly behind it, it *sometimes* can get confused and localize that sound to the front. It's rare, but it does happen. With 7.1, by using two rear speakers instead of just 1 as for 6.1, the effect is greatly minimized.

Also, having 2 speakers back there decreases the chance of localization over just 1, just because there are now 2 point sources and not just 1. For example, for 5.1, it is recommended to have dipole surrounds to lower the chance of localization. But, when you go to 6.1 and then 7.1, just the fact that you have more speakers back lowers the chance of localization so much that it is now *some* people's recommendation that you can use monopoles for all 4 speakers. Better imaging is the primary benefit.

 

[Philip Brandes]

And Meridian--they've also supported a 7.1 speaker configuration for years. It's interesting that these two companies, who are at the forefront of surround decoding technologies, both came to the same conclusion about the number of speakers needed for seamless immersion, a conclusion since ratified by THX, Dolby and DTS.

Cheers,
Philip Brandes

 

[John Garcia]

I don't know if you noticed, but 7.1 is an even number of speakers: 6 (sub tecnhically does not count). 7.1 ALREADY has 2 side surrounds and 2 rears...

 

[SvenS]

There is a psycho-acoustical effect called "reversal". When the human brain hears a sound directly behind it, it *sometimes* can get confused and localize that sound to the front. It's rare, but it does happen. With 7.1, by using two rear speakers instead of just 1 as for 6.1, the effect is greatly minimized.

This is not the case if the Rear Surround is high enough and pointing down though.

 

[AhsanR]

Is 7.1, really worth it?

I really want 5.1, but if 7.1 is really worth it, I will plunk down the extra money.

 

[Kevin C Brown]

Ahsan- If you have the space and the denaro, I say at least *try* 7.1. If you don't like, you can always go back to 5.1. But I've never actually heard of *anyone* who's tried 7.1 and *not* liked the improvement in the rear soundstage that results.

Sven- The problem with putting the rear surround speaker up high enough to eliminate reversal, is that now you are *under* the sound field, and not *in* it.

I found this out when I switched from 5.1 with dipole surrounds the recommended 30" higher than ear level, to towers *at* ear level. For example, instead of feeling like I was *underneath* the action in the 1st 20 min of Saving Private Ryan with the dipoles, I felt like I was *in the middle* of the action with the towers.

 

[AhsanR]

I'm worried I'm gonna blow my money, and as of right now, I'M ON A BUDGET..... thats why I am very VERY hesitant in purchasing.

I'm new to HT, so tell me something, how often are the rear channels used?

 

[SvenS]

Sven- The problem with putting the rear surround speaker up high enough to eliminate reversal, is that now you are *under* the sound field, and not *in* it.

If this were true then Dolby Labs (Dolby Digital) doesn't know what they are talking about because they say that surrounds should be ABOVE the listener not at ear level. The front stage should be at ear level though. But what does a company who pioneered surround sound know! And every theater I have been in has their back surrounds up considerably higher above the listeners.

 

[Philip Brandes]

Sven,

Reversals can occur at any point along the median (center) axis equidistant between the ears; elevating a single rear speaker does not solve the problem. Using more than one rear speaker, however, does--which is why Dolby, THX, and dts all take that approach.

Cheers,
Philip Brandes

 

[Dave Moritz]

I could go for 8.1 if it was in the configuration like SDDS is in. I am not a big SDDS fan but the idea of dual center channel is nice. IMHO this would work really nice for projection setups with 110" + screens .

 

[Kevin C Brown]

Sven- I have had the surrounds up high. I've had them at ear level. I much prefer the sound I got at ear level. The speakers were a little bit more localizeable, but I preferred the greater amount of detail that results. Although now I have them all about 1 ft above ear level. This seems to be the consensus for the best placement for Logic 7 and for THX Ultra2. (The detail is still there, and because the angle to my ears at the best listening position is still less than 15 deg, I don't get much high freq rool off. See below. But helps with localization.)

I agree, the *old* recommendation for DPL was surrounds up high, because the content in the surrounds was almost exclusively ambient material. But now with DD/DTS/DD EX/DTS-ES where there is now a lot of actual discrete steering within soundtracks, the "recommendations" that I have seen have slowly changed to encompass that, and that is to lower the surrounds.

Ever see an off-axis freq response from any speaker? The highs get major-league rolled off.

If you ever have a chance, I recommend you try it.

Oh yeah, in one of the reviews in the Jan SGHT, I was actually really surprised that one of the reviewers mentioned that *he* thought the best sound in his room was with all monopole surrounds/rears at ear level. And? That is without a doubt the best setup for multichannel music. Kind of neat that it works well for HT too.

 

[SvenS]

I agree, the *old* recommendation for DPL was surrounds up high, because the content in the surrounds was almost exclusively ambient material. But now with DD/DTS/DD EX/DTS-ES where there is now a lot of actual discrete steering within soundtracks, the "recommendations" that I have seen have slowly changed to encompass that, and that is to lower the surrounds.

I can only refer you to Dolby Labs website that show *NEW* recommendations for DD-EX saying surrounds should be placed ABOVE the listener not at ear level. You may prefer the surrounds at ear level (which is fine) but don't post info that all discrete surround formats should be placed at ear level when Dolby Labs who pioneered surround sound recommends surrounds above the listeners ear level! We are all here to help each other out but it doesn't help when someone passes off their preferences as the definitive specs as recommended by developers.

Link Removed

Note the statement "If you use a single rear surround speaker, center it behind the listening area at the same height as the side surround speakers, preferably above ear level."

 

[Kevin C Brown]

Although now I have them all about 1 ft above ear level. This seems to be the consensus for the best placement for Logic 7 and for THX Ultra2.

Now, where do I say that there is any official recommendation for surrounds/rears at ear level?

1 ft above ear level, is, ... well, ... *above* ear level.

And,1 ft is, er, ... *lower* than the 30" originally recommended for DPL.

 

[SvenS]

I agree, the *old* recommendation for DPL was surrounds up high, because the content in the surrounds was almost exclusively ambient material. But now with DD/DTS/DD EX/DTS-ES where there is now a lot of actual discrete steering within soundtracks, the "recommendations" that I have seen have slowly changed to encompass that, and that is to lower the surrounds.

Oh yeah, in one of the reviews in the Jan SGHT, I was actually really surprised that one of the reviewers mentioned that *he* thought the best sound in his room was with all monopole surrounds/rears at ear level. And? That is without a doubt the best setup for multichannel music. Kind of neat that it works well for HT too.

The discussion I was involved with had to do with DD & DTS formats not Logic 7 or THX Ultra 2 but even so your above statement is talking about the DD & DTS formats and you are saying that instead of up higher they should be lower and since I doubt you are talking about lower as in on the floor then the next step would be ear level which is NOT the recommendation from Dolby Labs!

 

[Martin Rendall]

AhsanR,

I'd say not, if you are on a budget. I have 7.1, but I only use the rear two for movies encoded for a rear center. Sure, it sounds better than 5.1, but not the cost of two matching speakers and an amp better. IMHO, 7.1 is *way* into the deminishing returns curve.

Martin.

 

[Kevin C Brown]

Hey Sven, let's see if you can understand, one more time:

1 ft above ear level is still above rear level.

And, 1 ft above ear level, is still *lower* than the old recommendation of 2 - 3 ft above ear level.

Got it? That's exactly what I wrote, and that's exactly what I meant, no matter how many times you reference "Dolby Labs" in a sentence with exclamation points.

I said I had *tried* tower surrounds with the tweeters at ear level, that I preferred the sound vs dipoles way up high. And I mentioned the SGHT review where the reviewer also echoed that same sentiment. I never said that tweeters at ear level were an official recommendation by anyone. Please reread my posts again if you are confused.

 

[Sacha_C]

"I don't know if you noticed, but 7.1 is an even number of speakers: 6 (sub tecnhically does not count). 7.1 ALREADY has 2 side surrounds and 2 rears..."

The ".1" is the sub, the "7" is the number of speakers, there are 7 speakers + 1 sub in 7.1