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My Take on 5.1 6.1 and 7.1 for DVDs and Gaming

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January 21, 2004 7:24:00 PM

PC Speakers:

(x/y) x=number of front speaker, y=number of surround

2.1 (2) Left, Right
4.1 (2/2)Left, Right, Surround Left Surround Right.
5.1 (3/2)Left Adds Front Center
6.1 (3/3)Adds a Back Center.
7.1 (3/4) Splits Back into Back Left and Back Right

The .1 represents the fact that the sub woofer which doesn't have its own channel Instead the frequencies below the crossover frequency are redirected from other sources. This can be done by a sound card, receiver/decoder or the sound cards. Never redirect LFE more than once!

Low frequencies are perceived as unidirectional so this is adequate for home theater use.

Home Theater Standards:
(Analog)
Stereo = 2.1 (Left,Right)
Dolby Surround = 3.1(3/1)(Left,Right,Rear)
Dolby Pro Logic =4.1(3/1) (Left,Center,Right,Rear)

(Digital)
Stereo = 2.1 (Left,Right)
Dolby Pro Logic 2 =4.1 Same as Pro Logic but digital.
Dolby Digital(AC3) = 5.1(3/2), DTS same at higher bit-rate.
Dolby Digital Ex = 6.1ch (3/3), DTS ES same at higher bit-rate).

Theater Standards:
Dolby Stereo (Analog) originally 4.1 (3/1) now 5.1
Dolby Digital/DTS 6 (3/2)+1 (real sub woofer channel)
Sony Dynamic Digital Sound 8 (5/3)+1 (7.1 with sub woofer channel)

SSDS names the speakers differently than Home Theater 7.1. (left=left center, right=right center, left surround = left, right surround = right, back left = surround left, back right = surround right)

Home Theater Experience:

What happens when your decoder supports more speakers than the source?

5.1->6.1 Create Back Center from Surround Left and Right.

6.1-7.1 Back Center Channel is played through both back speakers. (All current DVDs are 6.1 or less)


Is 5.1->6.1 an improvement? Slightly if you have a large living room.

Is 5.1->6.1 ever worse? Most people feel its always better, others argue it varies on a case by case basis. Many receivers have an option to ignore the 6th speaker when you have a 5.1 source.

Is 6.1->6.1 an improvement? Yes, if the 6th channel is really discrete and not them just mixing the surround channels for you. Otherwise it really just 5.1->6.1.

Is 6.1->7.1 an improvement? Not really, it does give you an extra speaker to fill a extra large room. If your room is large enough that you feel the need 2 Left and 2 Right Speaker then 7.1 is probably for you.

Is 7.1->7.1 an improvement? Doesn't exits for home use.
Thats why they have 7.1 "ready" receivers rather than actual 7.1. If a home theater version of SDDS is released (or a 7.1 of Dolby Digital or DTS) then owners of a 7.1 receiver will have to buy add a 7.1 decoder to use it.

My guess it that we won't see this until blue-laser video disc are released.

PC vs Home Theater System:
Obviously it makes no sense to have a high end sound card/receiver and use low quality speakers.

A high end PC sound card will simply never sound as good as a mid-ranged receiver because there is simply too much electromagnetic interference inside your computer.

A $300 to $700 professional audio interface (costs too much to call them sound cards) are able to compensate for all this noise, but at a price. Plus you get no 5.1 and horrible game support.

A high end sound card with high end speakers may well sound better than the cheapest home theater kits, but will be far less powerful.

A digital connection to an external digital speakers (digital decoder using PC speakers), will eliminate the interference. A downside is high end PC speakers can be just as expensive, sound no better and provide far less power when compared to mid range Home Theater Speakers. On the plus side you save money because you have to buy a $400 digital receiver before you can take advantage of those wonderful home theater speakers.

An analog connection to a receiver gives your PC the power (and potential quality) of a home theater speakers, but you still have the interference.

A digital connection to a digital receiver gives you the best possible sound, since you can pass the signal directly to the receiver for Decoding.

Even a cheap integrated sound card with digital out will render perfect DVD sound when connected to a digital receiver.

Of course the cheapness of the card will come back to haunt you when you are playing a game, in which case the card still has to do considerable audio processing, just no digital to analog conversion.

Also many 5.1 cards with digital out are not capable of encoding to 5.1. My Sound Blaster 5.1 only sends a 4.1 digital signal to my receiver when playing games. My CMedia only sends a 2.1 signal when it is not simply passing through audio form a DVD.

AC3 DivX:
In theory you can set AC3 filter to pass through without decoding, so it should work just like playing a DVD. In practice it is somehow down mixing to 4.1 Dolby Pro logic (left,center,right,rear). I am not sure what is causing this.

If you have a sound card that supports 5.1 Dolby digital encoding then you can get full 5.1 sound from a DivX by having AC3 filter render it for 5.1 speakers.


Gaming:

True 6.1 makes it a lot easier to locate sounds. 7.1 is also an improvement, but to a lesser extent.

5.1->6.1 is usually an improvement over just 5.1. Since rear sounds are actually coming form behind you.

6.1->7.1 Can't hurt. If you think 6.1->7.1 gives you more accurate positioning then move the back speakers closer.
Gaming 7.1 to 7.1. I hear this help a little, but the effect isn't as great as moving form 5.1 to 6.1.
I wouldn't pay extra for 7.1, but if a 7.1 had better features than a 6.1 I would buy it for those reasons.

Headphones:

Quality Headphone's are great for 3D gaming (your characters virtual head to position sound works just as naturally as moving your actual head in real live. They are definitely the better choice for gaming if you keep your 5.1 speaker centered on your couch.

My Gear:
PC #1 CMedia with optical out connected to Pioneer VSX-D912K 7.1 Receiver, PC #2 SB Live 5.1 coax SPDIF to same receiver. 5.1 Speakers Centered on couch. High quality headsets for gaming.

I used to have an analog connection to a slightly defective low receiver that lacked digital in.

Yesterday was the fist time a played a DVD with DTS sound. It was a religious experience! <P ID="edit"><FONT SIZE=-1><EM>Edited by codesmith on 01/21/04 04:38 PM.</EM></FONT></P>

More about : dvds gaming

January 27, 2004 10:22:10 AM

I'm sorry that I don't really have the time to get into much detail here but i have to correct some of the things you say, otherwise your post will confuse others or give them the wrong impressions...

Quote:
"PC vs Home Theater System:
Obviously it makes no sense to have a high end sound card/receiver and use low quality speakers.

A high end PC sound card will simply never sound as good as a mid-ranged receiver because there is simply too much electromagnetic interference inside your computer."

That is so Not true. What do you think is used to produce modern music?. I don't know what is your notion of 'hi-end cards' but let me tell you that true 'hi-end' or 'hi-quality' cards battle it just fine!

Quote:
"A $300 to $700 professional audio interface (costs too much to call them sound cards) are able to compensate for all this noise, but at a price. Plus you get no 5.1 and horrible game support."

Not true. First of all, depending on your needs you can start with less than $300 and ALSO get 5.1 and DECENT game support!

Quote:
"A high end sound card with high end speakers may well sound better than the cheapest home theater kits, but will be far less powerful."

I have to tell you it took me awhile to realise that you did not include an amplifier in your example. Why would someone want to get a high end card and speakers to be used without external amplification eludes me. If you do that then you negate any benefits that you are after in the first place. Any unwanted effect that you think is there will be most probably drowned in the computer's hum...


Quote:
"A digital connection to an external digital speakers (digital decoder using PC speakers), will eliminate the interference. A downside is high end PC speakers can be just as expensive, sound no better and provide far less power when compared to mid range Home Theater Speakers. On the plus side you save money because you have to buy a $400 digital receiver before you can take advantage of those wonderful home theater speakers. "

Like i said above, WRONG. There is no problem with interference and you HAVE to spend that money for amplification. If you not then there is absolutely no point to go after a hi-end card or speakers. Without it you degrade quality, period. What you are saying is going to potentially confuse those who don't know much about it...

Quote:
"An analog connection to a receiver gives your PC the power (and potential quality) of a home theater speakers, but you still have the interference."

Not true. I don't know what 'hi end' cards you are familiar with but i'm afraid they are the wrong ones.

Quote:
"A digital connection to a digital receiver gives you the best possible sound, since you can pass the signal directly to the receiver for Decoding.

Even a cheap integrated sound card with digital out will render perfect DVD sound when connected to a digital receiver."

That's a myth that many believe in. I don't have the time to tell you in how many ways this can be untrue. A digital-out on it's own means nothing. Not to mention the fact that what you're talking about involves lower-spec DACs in the final stage resulting in a much worse sound than you'd get with good quality DACs that reside in the card itself.

To wrap it all up, you CAN get a card that is REALLY hi-quality for much less than $300 with VERY serious 5.1 and great gaming. But you should do that ONLY if you intent to use good quality multi-channel amplification and good speakers (of course i'm not talking about cheap pc speakers). Only THEN you will have hi quality results. If you're not prepared to go that way then there is no point putting together a rig that has one or more weak links. Remember, the sum will be equal to the weakest link.

And my point is you CAN have it. So, please correct your post or change it somehow, otherwise many ppl will be missled by it.
I don't have the time to post more now (although i want to)but i can help you with anything you might need...

Take care.
January 30, 2004 12:11:37 AM

Heh, thanks for straightening me out on the interference issue.

Most of my thoughts on interference come from visiting websites and email correspondence with the manufacturers of the $500-$999 professional audio interfaces.

Obviously these guys have a vested interest in steering me away from the more moderately priced alternatives!

(If that was their intention it backfired. My uncle was willing to pay $700+ for a professional audio interface, but because of their concerns he decided to just pay twice as much and get a decent portable digital audio workstation equipped with a hard drive and CD burner.)

Additionally I should have been more specific in my criticisms of PC decoding paired with high end speakers. What I meant was "high end" PC Speakers, like the Klipsch Pro Media Series. They are great for use at your PC, but are a little underpowered for the living room.

PS Could you be a little more specific about which moderately priced sound cards have high quality DACs and offer "VERY serious 5.1 and great gaming". I would like to move by aged SB Live 5.1 to my old PC and am in the market for a replacement.
!