LinuxQuestions.org
Welcome to the most active Linux Forum on the web.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Software
User Name
Password
Linux - Software This forum is for Software issues.
Having a problem installing a new program? Want to know which application is best for the job? Post your question in this forum.

Notices

Reply
 
Search this Thread
Old 05-31-2008, 10:52 PM   #1
Lunpa
LQ Newbie
 
Registered: May 2008
Location: Ripon, Wisconsin
Distribution: Debian
Posts: 8

Rep: Reputation: 0
surround sound on a stereo sound card.


Hello everyone.

I've had a surround sound set for a while now, and a desktop with a normal stereo sound card, and a partially working surround sound card.

Long story short, I'm not interested in making the surround sound card work.


My surround sound system has an adapter so that rather than plug in the 3 8th inch stereo plugs into a device with 3 8th inch stereo jacks (such as a computer's sound card), it can instead plug the front and rear channels into a pair of RCA mono plugs (the red/white jacks that you'd see on a dvd player or video game system); the center channel is not used in this set up, instead, I press a button on the center speaker, and it produces it's own based on the front and rear stereo channels.

I also have an adapter that splits a single 8th inch stereo plug into a pair of mono RCA jacks (red/white)!




Is it possible to make my stereo sound card function like a surround sound card in software, and then multiplex the surround sound channels onto a single stereo channel, like a dvd player or a video game system would? (and any idea as to how this can be done?)
 
Old 05-31-2008, 11:25 PM   #2
pinniped
Senior Member
 
Registered: May 2008
Location: planet earth
Distribution: Debian
Posts: 1,732

Rep: Reputation: 50
"Is it possible to make my stereo sound card function like a surround sound card in software, and then multiplex the surround sound channels onto a single stereo channel, like a dvd player or a video game system would? (and any idea as to how this can be done?)"

Using existing equipment: no

The 'fake' surround sound on your multi-speaker system simply adds a small delay to the signal, attenuates it and mixes it with a tiny bit of the signal from the other channel, and puts it out the back speaker.

To get 'surround' effects with only 2 speakers, provided you have a distinct audio stream for the back speakers, the rear speaker audio is delayed in time with slightly different delays depending on whether the output will be at left channel or right, and the signals are mixed in with the channels. All variations of the ancient 'Phase 4' recordings/mixing of the 1960s and the results are impressive. When you feed such a signal to your faker system the result is probably not as good as on stereo - the sounds coming out the back just become a bigger jumble of noise and interferes with the carefully planned effect that was meant to be achieved with 2 speakers.

Now with modified hardware - can you multiplex several signals onto a single wire? Not with a good amplifier - top quality amplifiers have a pretty good response up to several megahertz. The amplifier's incredible frequency range aside, you will need filters, signal mixers, and a carrier oscillator to achieve what you describe. Better to buy an X.1 surround sound card.
 
Old 06-01-2008, 12:21 AM   #3
Lunpa
LQ Newbie
 
Registered: May 2008
Location: Ripon, Wisconsin
Distribution: Debian
Posts: 8

Original Poster
Rep: Reputation: 0
I'm confused by your reply, so I'll reiterate:

My so called "fake" surround sound system consists of four satellite speakers, a center speaker, and a sub; it is a normal 5.1 surround sound system.

I have a small adapter which came with the system, which on one end has two 8th inch stereo plugs, and two RCA plugs; the front and back channels from the sound system plug into 8th inch stereo plugs. The red/white RCA plugs from typical a/v things plug into the other side of the adapter. The way I understand it is, the device provides the surround sound channels in a multiplexed form over the stereo plugs.


Also, in case we're rusty on the counting, the above comes to a total of 6 speakers. This is a reasonably modern system, that I purchased about a year ago, not some concoction from the 60's. My surround sound system is a 5.1 surround sound system.


I'm not interested in doing any hacks with hardware (in that, I'm not going to modify anything or make something I don't already have); I'm interested in making one type of currently existing modern technology (my computer) behave like another type of currently existing technology (my wii, dvd player, vcr, whatever).
 
Old 06-01-2008, 12:36 AM   #4
Lunpa
LQ Newbie
 
Registered: May 2008
Location: Ripon, Wisconsin
Distribution: Debian
Posts: 8

Original Poster
Rep: Reputation: 0
God bless wikipedia, here's a better clarification of what I'd like to do with this:

Is it possible using a normal stereo card to configure alsa to output surround sound in the dolby pro logic 2 format?




http://en.wikipedia.org/wiki/Dolby_Pro_Logic
"Dolby Surround/Pro Logic is based on basic matrix technology. When a Dolby Surround soundtrack is created, four channels of sound are matrix-encoded into an ordinary stereo (two channel) sound track by using phase shift techniques."
(pro logic 2 is the same thing, but with 5.1 surround sound)
 
Old 06-01-2008, 10:46 AM   #5
knudfl
LQ 5k Club
 
Registered: Jan 2008
Location: Copenhagen, DK
Distribution: pclos2014, Slack14.1 DebWheezy, +50+ other Linux OS, for test only.
Posts: 13,522

Rep: Reputation: 2503Reputation: 2503Reputation: 2503Reputation: 2503Reputation: 2503Reputation: 2503Reputation: 2503Reputation: 2503Reputation: 2503Reputation: 2503Reputation: 2503
Try these keywords for Google : encode pro logic 2
and...encode pro logic 2 linux
http://www.driverheaven.net/3-d-audi...c-encoder.html
It is not alsa, it is dsp-code, I hope you can find out, how to get it to work.
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Virtual surround sound (Audigy SE Sound Card) alan1s Linux - Newbie 3 08-09-2009 06:00 PM
Dynex 5.1 Surround Sound Card Question hexter Ubuntu 1 10-21-2008 12:38 PM
5.1 Surround Sound, with On Board Sound Card computergee Linux - Hardware 7 02-25-2006 12:03 AM
Virtual surround sound (Splitting stereo into more channels) redarrow Linux - Software 1 07-14-2005 12:18 PM
Surround Sound and Audigy Card Memzback Linux - Newbie 4 12-01-2004 04:03 PM


All times are GMT -5. The time now is 06:18 PM.

Main Menu
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
identi.ca: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration