5.1 question

[tampaud]

OK, here's a stupid question. I know DVDs usually have 6 channels of audio (5.1), and I know my stereo supports 5.1 and has 6 speakers. Yet, the connection between my DVD player and my stereo is simply a stereo RCA cable. So how are the 6 channels of audio travalling over 2 cables? Thanks.

 

[supervij]

I'm very much a beginner myself, but I don't think you're getting 5.1 out of those red & white RCA cables. The best you can get is 2.0, either straight from the stereo option on the DVD, or downmixed from the DD or DTS 5.1.

If your receiver supports 5.1, then it likely has various surround modes (like PLII and Neo:6), and that's why you're hearing sound out of all your speakers. But it's not true 5.1, just a "faux" surround made out of the 2.0.

If you were to use a digital coax cable or a digital optical cable, then you'd be getting true 5.1 (or 6.1) from the DVD player. And those six (or seven) separate channels of information are travelling in ONE cable! Crazy!

cheers,
supervij

 

[AVRat]

It's not, you're only getting two of the 5 through the stereo analog connections. Which receiver? The .1 is for subwoofer.

 

[j_garcia]

Like Supervij said, the only way you can get true 5.1 surround is with a digital connection. You can also use 6 analog connectors between the player and receiver if they both have the connection, but a single digital connection is a lot simpler in most cases.

 

[markw]

Yes, you CAN get those digital 5.1 channels through one RCA cable.

you are passing a digital signal. not an old fashioned analog signal which DOES require a different conenction for each channel. A digital can pass as many channels as you need on one connection.

A digital signal can be passed in two ways. One is through "Toslink",that glass/plastic abomination with those funky connectors on the ends or by simply using a regular old coaxial cable with RCA plugs on the end. That's called a "Digital Coaxial" connection.

You should be using the "digital coaxial" outputs on the DVD player and inputs on the receiver. I believe thesr are orange in color, but you may want to check your manual. If you're usingthese you will be abpa to pass 5.1, 6.1 or whatever digital signals you need.

You wouldn't be using the red and white jacks on the DVD player to the receiver. Those are for two channel analog stereo. Ifthat's whatyou're doing now, then you are only passing two channels and one of the unit's internal processors is "synthesizing" other "channels" out of the two.

but, all is not lost. You don't need an "official" digital coaxial cable to get the real thing. Virtually any coaxial cable with RCA plugs will work. ...even one side of that red/white cable. got the hint?

 

[Buckle-meister]

A digital signal can be passed in two ways. One is through "Toslink",that glass/plastic abomination...

Why is an optical cable an abomination?

Regards

 

[markw]

When all is working well toslink is no worse than a digital coaxial signal.

Why is an optical cable an abomination?

Regards

Well, first off, the signal needs to go through two additional steps. On the source side the electrical signal needs to be converted into light pulses. Then, it's fed out through a flaky plug to aconnector that must be insetered exactly correctly in order to pass the light correctly into an optical cable that cannot be bent too much. Now, at the receiver it then is fed through another of those funky connectors into another plug and goes through another (re)conversion to change the light pilses back to an electrical signal.

http://www.audioholics.com/FAQs/coaxvsopticaldigital.php

 

[j_garcia]

Virtually any coaxial cable with RCA plugs will work. ...even one side of that red/white cable. got the hint?

This isn't exactly right. A coaxial digital cable MUST be a 75 Ohm cable for it to work properly. Analog audio cables do not have to be 75 Ohm, so it is anyone's guess if a given cable is or isn't without testing it. So your best bet is to use a standard composite VIDEO cable, which should always be 75 Ohm.

Even with the extra decoding step, there is nothing wrong with optical. I prefer coaxial becasue of the sturdier connection and recommend using that if that is an option, but there isn't a big difference between the two.

 

[markw]

And, as I've said many times before...

This isn't exactly right. A coaxial digital cable MUST be a 75 Ohm cable for it to work properly. Analog audio cables do not have to be 75 Ohm, so it is anyone's guess if a given cable is or isn't without testing it. So your best bet is to use a standard composite VIDEO cable, which should always be 75 Ohm.

Most today are. And, for the short distances involved, imnpedance isn't even a real issue. Heck, even a coathanger will work.

let's keep it real world and not mystify this hobby.

 

[Buckle-meister]

I am aware of the steps necessary to pass content from a player to a receiver (for example), though I wouldn't have considered the connection between the two as 'flakey'.

It's not all bad. Toslink has the advantage over coaxial when it comes to interference.

You forgot to mention that.

Regards

 

[markw]

Didja even bother to read the link I provided?

I am aware of the steps necessary to pass content from a player to a receiver (for example), though I wouldn't have considered the connection between the two as 'flakey'.

It's not all bad. Toslink has the advantage over coaxial when it comes to interference.

You forgot to mention that.

Regards

No!

 

[Buckle-meister]

Sure I did :

...using optical cables...may help to reduce common mode noise.

 

[j_garcia]

Most today are. And, for the short distances involved, imnpedance isn't even a real issue. Heck, even a coathanger will work.

let's keep it real world and not mystify this hobby.

75 Ohms is part of the coaxial digital spec, period. It's a fact, not a myth. Using a cable that is not 75 Ohm can result in sound drop outs. MOST is a generalization that you should not make about analog, because it simply isn't true. Distance doesn't matter here, since we are talking about the impedance of the CABLE, which should be 75 Ohm regardless of length...

 

[markw]

You can argue theory all you want.

I'll stick to what works in the real world.

I suggest the kid try using his existing cables and report back. It won't cost hin one red cent.

After all, it's him I'm trying to help and educate. Y'all already seem to know too much to be able to learn anything.

I've only been playing in this sandbox since I built my first tube amplifiers in the early 60's so I guess I have no idea what I'm talking about.

 

[markw]

Apparantly only what you chose to read. Now, how about the whole qute.

Sure I did :

Using optical cables for your digital connections may help minimize susceptibility of coupling RF noise into the line and reduce loss for long runs (10 feet or more). However, optical cables tend to be more costly and sensitive to abrupt external forces, which may potentially weaken the connection over time.

Well, at least I know where you're coming from. ...and here I thought you had a head on your shoulders but you would rather play games. pity...

 

[j_garcia]

I'll stick to what works in the real world.

I suggest the kid try using his existing cables and report back. It won't cost hin one red cent.

After all, it's him I'm trying to help and educate. Y'all already seem to know too much to be able to learn anything.

I've only been playing in this sandbox since I built my first tube amplifiers in the early 60's so I guess I have no idea what I'm talking about.

Well, using an existing VIDEO cable probably won't cost him one red cent either, AND there's a 100% guarantee that it will work....

We're ALL trying to give good info, or maybe you're the only one who knows what they're talking about?

 

[markw]

It seems you have a misunderstanding as to what's going on here.

... or maybe you're the only one who knows what they're talking about?

You seem to be the one intent on proving me wrong. I'm not trying to prove anything.

I never denied that 75 ohm cables will work. You are the one that seems to be saying that his red/white cables won't work.

...and, I dispute that. Having used a 20+ year old coaxial audio cable of unknown pedigree for a digital interconnect with no negative issues gives me confidence in my stance.

Something I learned a long, long time ago is that sometimes you spend a lot of money only to later learn that you didn't have to spend a lot of money to get the same results.

 

[j_garcia]

I never denied that 75 ohm cables will work. You are the one that seems to be saying that his red/white cables won't work.

...and, I dispute that. Having used a 20+ year old coaxial audio cable of unknown pedigree for a digital interconnect with no negative issues gives me confidence in my stance.

That would be because there isn't a 100% guarantee that it will work, otherwise I wouldn't have mentioned it. Just because it worked for you isn't a guarantee, is it?

 

[markw]

True, very true.

That would be because there isn't a 100% guarantee that it will work, otherwise I wouldn't have mentioned it. Just because it worked for you isn't a guarantee, is it?

But there's no guarantee the sun will rise tomorrow either but I'll still give you 1,000,000 odds that it will.

...you can pay me the day after tomorrow.

 

[mtrycrafts]

This isn't exactly right. A coaxial digital cable MUST be a 75 Ohm cable for it to work properly. .

Well, yes and no
With such a short run of digital cables, even coat hangers have been shown to work without signal degradation The famous coat hanger experiments of a number of years ago. Too bad the links to this experiment no longer working.

And, 120Volt power extension cords have also been shown to work with even very long cables:

http://www.provide.net/~djcarlst/abx_vid.htm


Check out the 150 ft extension cables on exterior scenes No matter how you slice it, that is a very long cable.