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Old 11-17-2010, 04:10 AM   #1
tpreitzel
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Virtual 5.1 Sound


My 5.1 speaker system just died in a storm ... oh, well.

After removing the system, I realized how much space it was occupying. Although I love my DTS 5.1 sound, is it possible to emulate a 5.1 system on two speakers? I've heard of ALSA's vdownmix, * but I haven't tried it. Basically, I want to play my 5.1 DVDs as closely as possible to a real 5.1 system, but without the hassle.

I was thinking of possibly going wireless, but due to RF hazards, I'm removing most of my RF equipment. Any wireless devices will probably be based on IR (infrared). With that said, I'd like to keep the focus of this thread on emulating 5.1 sound on stereo speakers and headphones. TIA

* http://www.rpgameplace.de/blog/index...with-ALSA.html

Last edited by tpreitzel; 11-17-2010 at 04:22 AM.
 
Old 11-18-2010, 12:25 AM   #2
lumak
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You really shouldn't be concerned about your RF/EM exposure from consumer goods unless you have a predisposition to cancer. For example, a chest X-ray contains as much as the average exposure for the entire year. And Obviously, you don't want to be pointing lasers and other such devices at your skin for long periods of time. If you are really concerned about it, you shouldn't even have your computer sitting next to you, and your printer should be on the other side of the room.

Aside form that, From my experience with software the phases the speakers, it really only seems to move the stereo audio position from your viewing area to by your head so it sounds like it coming from there. It's an interesting effect but really isn't a substitute for 5.1

There are head phones that give you 5.1... but I think those are a bit costly.
 
Old 11-19-2010, 05:09 PM   #3
tpreitzel
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lumak -

Regarding RF, I've read quite a bit on the subject. Sure, the potential hazards are controversial, but in my case I'll probably stick to virtual 5.1 until manufacturers offer wireless substitutes based on IR. Frankly, I'm rather disappointed that manufacturers have seemingly abandoned IR in favor of RF. Yes, there are inherent problems with IR (LOS), but solutions have been designed that essentially fill a room with reflected IR that largely minimizes the LOS problem.

Since I just bought a cheap pair of 2.1 speakers with which to experiment a bit, I realize that even advanced technology based on psycho-acoustics will never really substitute for truly surround sound, i.e. 5.1 . Even with 5.1, the listener is supposed to be centered among the speakers which frequently doesn't occur.

Last edited by tpreitzel; 11-20-2010 at 02:59 AM.
 
Old 11-20-2010, 09:40 AM   #4
lumak
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That much reflected IR has its own hazards associated with it. Invisible light tends to be harmful in various ways... Not to mention, IR is just a step up from microwaves.

Anyway, 5.1 systems for desk computers just feel silly. It's not a proper relaxed setting to be watching movies anyway. Your best bet is wired 5.1 in the living room.

As for calibrating them, a good 5.1 system will allow you to adjust the phase and the volume of each speaker individually to allow the best hearing position to be where you want it. This way you don't have to be in the center of the room, just the center of the focal point after tweaking all the settings.
 
Old 11-20-2010, 07:21 PM   #5
tpreitzel
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We'll just have to agree to disagree about the relative potential hazard of RF versus IR. Apart from lasers, IR is incoherent light, i.e. non laser, so reflected IR is simply emitted as basically undetectable heat to the human body. Lasers emitting IR, coherent light, would be a different matter.

Personally, I was quite satisfied with my software, computer-based 5.1 system. Instead of wasting, in my opinion, money for a separate hardware-based theater system consisting of 1000w amplifier, Klipsch speakers, etc., just buy a pair of stands for the rear speakers of a software, computer-based 5.1 system. Then, move the rear speakers as appropriate so the listener is centered. I'll bet most people with computer-based 5.1 systems don't even do the latter, i.e. buy stands and relocate the rear speakers as necessary. Sure, it's not as good or comfortable as a separate 5.1 system, but it's significantly more portable and lower in cost.

Regardless of the type of 5.1 system, both designs consume significant amounts of space. Sure, flat speaker wires can be run along the baseboard, but the ideal solution in my opinion is a software, computer-based 5.1 theater system with links of reflected incoherent IR light connecting the rechargeable, battery-powered rear speakers on adjustable stands. *

In the interim until I'm able to locate that personally ideal 5.1 system, I'll experiment with this low cost 2.1 system and software-based psycho-acoustics.

* I'd even be willing to use a transmission system using household wiring for AC-powered rear speakers if possible... Yeah, it'd be less flexible than battery-powered rear speakers using high-density cells based on lithium, but I can always move a chair if necessary. I'll have to investigate whether audio can be cleanly transmitted via household wiring ...HomePlug? Now that HomePlug AV2 is right around the corner, ~ 6 mo. away, we're now seeing prices drop for HomePlug AV equipment which can still stream HD 720p/AC3 just fine so streaming stereo audio to two rear speakers will be a piece of cake with a couple of PC audio (3.5mm) baluns. hummmmmmmmmmmm! If I just buy an additional low cost set of speakers for the rear, I'll have 4.1 audio with the front speakers and woofer directly connected to the PC's sound card and data to the rear speakers streamed over the power line. Will it work, i.e. without delay between front and rear speakers? I don't know, but it should. If not, I haven't wasted much money on the rear speakers and I can ALWAYS use HomePlug AV equipment with other gear.

Last edited by tpreitzel; 11-21-2010 at 08:06 AM.
 
Old 02-06-2011, 10:16 AM   #6
tpreitzel
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Although I've strayed a bit from the opening question, the basic reason for the original question still remains, i.e. a solution to the mess of cables involving multi-channel audio.

My intention to use baluns for the rear channels via a HomePlug network failed because I completely overlooked the need to convert the analog signal into packets. I purchased two stereo baluns from MCM electronics and they work beautifully with cat5e or cat6 cable. With the baluns, the signal quality is very high although I'm currently using 50' of cat5e cable for the rear channels. Eventually, I'd still like a solution to eliminating this SOLE 50' cable. Currently, I'm unsure whether digitally streaming the audio for the rear channels is a viable alternative as it would likely require another computer or additional hardware to convert from ethernet to analog. Various initiatives exist which might help with deploying multi-channel audio eventually, e.g. AoE, AoIP, Ethernet AVB, etc...

Last edited by tpreitzel; 02-06-2011 at 10:27 AM.
 
  


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