July 14, 2004

7:39 PM

Audionazi-filter: I have just bought a Dolby 5.1 sound system. Please tell me why I should or shouldn't listen to my CDs, recorded in stereo, using all six speakers. [And slightly related: What movies should I rent for their brilliant 5.1 sound?]
posted by meech to (18 comments total)

Whatever sounds good to you. Seriously. If you like the way a CD sounds with some of the DSP effects turned on, go right ahead and enjoy it.

I do this for parties, where it's nice to have a little bit of music coming out of each of the speakers.
posted by majick at 7:46 PM on July 14, 2004

If you really want to know, take your favorite album, and play it on your new system. While it plays, switch among the options. You will find some options work better for certain music, while other options work better for other music. Think of your new sound system as an IE/Mozilla for music, and your music collection the internet. Browse away!
posted by Kwantsar at 7:48 PM on July 14, 2004

nb: I've been known to bi-wire, to make my own speaker cable, and other insane things.

short form: what majick and kwantsar said -- do whatever you think sounds better.

long form:

if the recording is stereo, the only possible faithful reproduction can be stereo. personally I listen to stereo cds in stereo only, and with 'effect off'.

if your two main speakers (you do have floorstanding horn-based loudspeakers, each weighing more than a small teenager, don't you? just kidding...not everyone likes horns) are positioned correctly in the room, and if you sit in the right place, and if the stereo cd was mixed decently, the overlap of the two channels will actually make available more voices than simply 2. (think about it, stereo has been around for a long time)

so forcing it into more real channels may work, or it may do awful things. I would lean toward awful, but it's like wine, or art, or any damned thing -- lots of people will tell you what's 'right', but you won't know until you try for yourself, and what you like is all that matters.
posted by dorian at 8:25 PM on July 14, 2004

Well, there's a big difference between using the lame-ass DSP effects (like "Hall", or whatever), and using the setting that most systems have to just distribute a stereo signal across all the speakers.

First of all, even in "stereo", your system is almost certainly using at least three speakers, since it's taking the lower frequencies and sending it to the subwoofer anyway.

Beyond that, my Marantz, as an example, has a "5-channel" setting that simply takes the original "L/R" stereo signal from the digital PCM stream, and distributes it evenly across all 5 speakers--the center speaker plays an even blend of "L+R", the two front speakers each play a proportional mix of something like 75%L/25%R, and the two back surrounds play either straight "L" or "R".

The result doesn't distort the tone or equalization of the music at all--it just fills the space with a well-separated stereo sound. I use it for all CDs, for the TV, etc., and it works great.
posted by LairBob at 9:02 PM on July 14, 2004

Many receivers actually have more than one system for distributing sound to the extra speakers. In fact my (cheap, two-year-old) receiver can do it with Dolby Pro Logic, Dolby Pro Logic II, and DTS. To me, DPLII sounds the best by a wide margin. But whether to use the surrounds, and which system to use for it, are definitely decisions to make between your own ears.
posted by coelecanth at 9:16 PM on July 14, 2004

depends on how you set up your receiver, if the sub is on for stereo or not -- in our case, the mains have 2x 12" woofers each, which very reliably reproduce down to ~70hz -- so subwoofer not so much needed (but by 50hz they are by no means perfect...). whereas people with more, well, 'portable' mains (ok yeah granted, that probably is most people) will generally want the sub to be on.

spreading the stereo signal evenly sounds like it might produce a pretty decent image, we never watch tv but I think I will have to give it a try just to see how well that works ^_^
posted by dorian at 10:00 PM on July 14, 2004

coelecanth, those systems you've described aren't just options for distributing sound across channels, but are actually encoding formats. They should be a distinct option on your system from the ability to just play a stereo signal across all 5 speakers.

The 2 Dolby Pro systems are actually a way of encoding a "surround" multi-channel image in a two-channel audio source signal--they require a sound source that's been encoded for those specific formats, so you can't take advantage of them with just any source like a normal CD. (For example, a lot of GameCube games will come with a certification for "Dolby Pro Logic II", even though the GC can only output a stereo L/R signal--it still comes out as a surround effect when the receiver's set to decode DPLII.)

DTS is another animal entirely. It's a format for encoding 5.1 surround sound, and competes with the "Dolby Digital" format. There's a huge debate among audiophiles over which is better--personally, I prefer DTS, but probably for all the reasons that would make an audio nut sneer. Nevertheless, again, a DVD has to be encoded with a DTS track to be able to use it. (You can actually get DTS-encoded audio disks, but they're generally not worth it--I've gotten a few, and the sound separation tends to be a bit gimmicky, like in the early days of stereo.)

There's lot more detail on the formats in places like here and here.
posted by LairBob at 10:17 PM on July 14, 2004

_{[coelecanth, you may well understand all that stuff already--I included the overview for the edification of folks like meech who are just getting up to speed on the wonders of home theater.]}
posted by LairBob at 10:24 PM on July 14, 2004

While the movies are absolute crap, I would suggest Star Wars Episodes 1 and 2, the most recent craptaculars from Lucas. Since Lucas also owns the THX stuff, the movies are total surround sound porn. There are loads of gratuitous spaceship fly-bys that send sound from your rear speakers to your front ones. And it's a terrific way to convince others you just made a good investment.
posted by mathowie at 10:28 PM on July 14, 2004

Another great disc for showing off the system is the newer "Fantasia" DVD, which was recorded and mixed for surround from the ground up. Sure, like most folks I'm emotionally attached to the original film, but the sequences in the new one are really some of the only "straight" music I've found that really works in a surround mix.
posted by LairBob at 10:49 PM on July 14, 2004

Hands down, the best sounding DVD out there is Saving Private Ryan. Get the DTS version if your receiver supports it.
posted by keswick at 10:50 PM on July 14, 2004

I listen to basically all my stereo music in Dolby ProLogic II 5.1. It does some queers things on occasion, like kill the vocals, but normally only on lower quality, lossily compressed files, and then only rarely. Some things can be great though and you'd think they were edited with such a system in mind. Three that come to mind:

"Idiotheque" by Radiohead
"The Private Psychedelic Reel" by the Chemical Brothers
"Decepticon" by Le Tigre
posted by ed\26h at 1:38 AM on July 15, 2004

Or you could go and buy the version of Pink Floyd's Dark Side of the Moon (SACD) that was remastered for 5.1 surround. I've still to get and try that one myself, mind you but reviews have been good.
posted by snowgoon at 2:19 AM on July 15, 2004

The Flaming Lips - Yoshimi Battles The Pink Robots 5.1 DVD Audio is nice. The album is remixed for 5.1, plus it comes with a collection of videos and color sequences. Also includes a summary of the 5.1 patterns for each song, such as how on one track each bass note changes speakers, in effect walking around the listener.
posted by the fire you left me at 7:18 AM on July 15, 2004

LairBob, Dolby Pro Logic II is actually a system for creating surround effects from any stereo source. Dolby Labs explains it here:

Pro Logic II from Dolby Laboratories gives you multichannel surround sound from any stereo source—CDs, tapes, videocassettes, TV broadcasts, AAC files, you name it.

DTS offers a technology called "Neo" that transforms any stereo mix into surround. DTS explains it here.

Systems like this seem to work really well for the stereo tracks on older movies. For music they are (to my ears) unobtrusive at worst and somewhat helpful at best -- although occasionally they'll get something stunningly wrong or right.

The best movie I've seen yet for surround effects was the recent Master and Commander.

Incidentally, many modern DVD players and receivers can also decode DTS, which is also available as a sound format on newer, high-budget DVD movies. The DTS format is either uncompressed or not lossy about its compression; it produces very clear audio with HUGE dynamic range. There's some tricks about getting it to work right but it can really pay off for any DVD that has it.
posted by coelecanth at 7:32 AM on July 15, 2004

Huh, I wasn't aware of that distinction regarding DPLII--I'd always seen DPL "I" and "II" lumped together, as formats that require an encoded source.

I'll give it a shot with some "normal" stereo sources, and compare it to the "5-channel" mode I described earlier--I think it's definitely going to be one of those situations where your ears need to make the distinction.
posted by LairBob at 8:08 AM on July 15, 2004

I concur with keswick: The D-Day landing in "Saving Private Ryan" is one of the most amazing things I've ever listened to in a home movie. The bullets, waves, yelling and shells come from ALL OVER the damn place during that scene. Whenever someone comes over that asks about the surround sound system, I play that scene (if they aren't war-phobic).
posted by grum@work at 8:13 AM on July 15, 2004

The re-mastered Dark Side of the Moon has 5.1 audio?
*rushes out to buy a copy, with memories of listening to Floyd in quadraphonic as a young person flooding back.*
posted by dg at 3:45 PM on July 15, 2004