Topic: What does 'surround sound' setting exactly do?

[Pike84]

That's about it: what does it actually do. As I've noticed, it alters the sound of mods somewhat, but other than that is unclear to me .

[Ian @ un4seen]

Yep, it only applies to MODs... it uses various amounts of delay to the left or right channel of each sample played, to give a "surrounded by sound" effect

[Pike84]

Ok . By the way, does XMPlay support real surround sound? Like as Winamp apparently supports only 4.1, and a guy who has five speakers, was interested about if XMPlay would allow him to use all of them.

[Zarggg]

To my knowledge, Oggs and MP3s only have, at most, two or three channels. I don't see why the player would be able to "create" more channels that the 4.1 or 5.1 would play through. Of course, if the speakers were able to be set in a 2-2-1 configuration, it might work (two speakers set to "left" channel, two speakers set to "right" channel, one speaker set to both channels) regardless of the player.

Of course, that's just theory, and precludes any knowledge of how SurroundSound actually works.

[Pike84]

That's about it, I guess. Just so that there would be more sources of sound. Some people also build home theatres and such, where it's useful. I'm not in need for that kinda stuff myself though, but I've heard there's even 7.1 around.. Nothing's enough for some, huh ?

[DanaPaul]

there's even 7.1 around..

The 7th speaker is a center rear channel.  Apparently game developers can use this to emulate a character sneaking up behind you.  A distinct advantage I might add

[Rah'Dick]

I'd LOVE to have Dolby ProLogic support. It's easy to code, by the way... There are some algorithms out there, I think.

[Pike84]

So... XMPlay doesn't have any kind of surround sound support at the moment?

[Rah'Dick]

Noup. And since (Winamp?) DSPs aren't supported, either, you can't even add surround.

[Ian @ un4seen]

I don't think you can get 4/5/7.1 output from a Winamp DSP plugin - a DSP plugin can only fiddle with what it's given, which is stereo.

But, anyway... I have been thinking of experimenting with extending the MOD surround stuff into multiple speakers - I am curious to see what could be possible

The reason I only say "MOD" is that there are more channels to play with, so more scope to do interesting things with multiple speakers... in comparison, there's not really much you can do with a pre-mixed stereo stream.

Btw, if your drivers have EAX (or other reverb/surround system), you can already listen to stereo output (from any player) with reverb/surround effects on multiple speakers

[Rah'Dick]

Ian, ever heard of Dolby ProLogic, which gets you REAL surround, decoded from a stereo signal? Every HiFi system features this today... And there's even a ProLogic Decoder for Winamp, I believe.

[Tsorovan]

What format are we talking about here? DTS? AFAIK, there's still no stand-alone usable decoder for playback yet. I know there's one in the works but it requires a 2GHz P4 :D
Or AC3?

Of course, some DVD players like for example WinDVD can play DTS...

Sure, the OGG format (theoretically) supports multiple channels but I have still not found any such files floating around.
MP3 does not.
Special WAV files can do it...file sizes would be incredible though.
So I guess you first have to decide what standard we're talking about here..."5.1" is pretty arbitrary.

Oh, I wouldn't call a 2.0 -> 5.1 converter (it's basically just multiple crossover algorithms aye?) REAL Dolby...
And to say every HiFi system features this today is lying. Quite a bit. Actually, a lot.

[Ian @ un4seen]

Ian, ever heard of Dolby ProLogic, which gets you REAL surround, decoded from a stereo signal? Every HiFi system features this today... And there's even a ProLogic Decoder for Winamp, I believe.

I think you would want an encoder? (your hi-fi would be the decoder) But, as Tsorovan says, I don't think that'd strictly be "real" surround... unless it's a pre-encoded stream (in which case there's no need to do anything extra to it anyway ), you only have left/right channels, the others would have to be just an effect generated from that stereo image. Your hi-fi probably already has an option like that built in?

But, anyway... if you can provide encoder specs/code/etc, I'll be happy to give it a look. Btw, aren't there licensing issues with using Dolby technology?

[Pike84]

I only took this up because a guy at Hydrogen Audio was dissatisfied with Winamp not supporting anything beyond 4.1. Not like I'd need it much myself, but if some people want it and it's possible, then why not?

By the way, does no one read the suggestions thread? There's now three of my posts in a row .

[Rah'Dick]

That's the cool thing about ProLogic: it was the first original method of decoding a surround signal from a normal stereo stream. Meanwhile there are more advanced algorithms as ProLogic II...

Anyway, you don't need a special encoder for "surround-encoded" stereo. EVERY stereo signal features encoded surround signals, you just have to decode them.
It works with the stereo phase differences between the channels...

I don't know about any licensing fees but all you had to do is rename your surround method to something like "phantom surround" or so

Sorry, don't have any example code snippets yet. All I know is that my stereo has a special chip for processing the surround signal.