I'd be interested to hear from anyone with experience in using a 5.1 surround sound system for delivering music designed to be a surround sound experience. By that I don't mean music mixed to present the instruments from the front speakers and then back-of-the-hall ambiance from the back speakers. I mean something more like 70's quadraphonic where some sound sources seem to be behind the listener, and front and back speakers are peers in a sense.

2 kinds of questions...

In home theaters folks are often encouraged to diffuse the rear sound by pointing the speakers at the rear wall or up towards the ceiling. But the speakers front and back are often identical, and many people don't bother. As a practical matter, in most installations could I, say, pan a sound from the front of the room to the back of the room without significant timbrel shifts?

Second question. I sort of have to do this on the cheap. I already have an interface that can send 6 line level signals out of my Mac from a different project. Any recommendations for an inexpensive home surround system that will take 6 line-ins, not just s/pdif from a dvd?

(I have 2 nice Genelec speakers for stereo mixing. As much as I'd like to buy 3 more and a subwoofer, that's more money than I'd care to spend. So I'm thinking I can mix to those in stereo to get levels and timbres right, and then use the less expensive 5.1 system purely for placement. Also I want to have both stereo and 5.1 mixes anyway.)

(Oh, I should mention this is for weird electronic music. No acoustic sources, no vocals, no attempt at reality required.)

Here's an idea I used to run by various LA studios... You go in the studio and say to the guy... here, lemme hear this DVD. I've been playing it at home and I'm SURE (!) I know what it sounds like.

The studio dweeb then looks at you like, duh, we can't play DVD's here...

so here's my suggestion. Follow it through.
Get yerself a modest (or better) Denon, like a 3805. Connect the CRouts of whatever you have - your board, whatever, to the AUX ins.

So to everyone...stop being a baby about balanced vs unbalanced. Grow up. Audio is audio. I would suggest putting a 10dB pot or resistor if you are using so-called +4 outs. That way the ENTIRE level chain will track through, and you can then set so that 0 VU on your BOARD = 85 (or 90 or whatever) dB SPL in the room at your listening position.

You can also connect a CD player, a DVD player, a video game, etc ad nauseum to the denon.

You can use the Denon's power amps or not; IF you were to use for example "studio" amps simply run the PRE out to the studio amp in. You could also use your "pro" amps JUST for the LR and run the C, Ls, Rs from the Denon's internal amps. Just be careful about the phase relationships, and fer godssake, turn the damn "distance" settings all to the same, and the lowest setting.

Now what you have is a studio control center. You have a calibrated volume control WHICH IS REPEATABLE; you can, if you want to bother, actually set the room's playback levels like a real film studio; you have built-in bass management so you can PROPERLY integrate a sub into your control room, and you can play back anybody ELSE'S Cd or DVD and A-B their mix with your mix off your board (or proTrolls, or nuendo, Waveslob, whatever...) and now YOU KNOW WHAT THE STUFF WILL SOUND LIKE IN SOMEONE ELSE'S HOUSE.

You can still use your fave version of whatever LR speaker; you can get more speakers and set'em up in 5.1, and yes as you mentioned, even if they are different, (for example the C is different from the LR and the Ls Rs are different still) as long as you yourself know and understand the LR speakers, an you match the panning levels correctly to your listening position, you don't need to overly worry about some timbre differences between the speakers.

OK, ideally in the studio you'd have 5 of the same, placed in the nice ITU configuration and panning would be butter smooth... but at least the above will get you going on a nice level, especially the comparison part.

Barry

Thanks for the interesting post. On a personal practical level, though, it's not really applicable to what I'm doing. What I'm working on is an almost $0 budget only using gear I already have. Fortunately that includes my G5 iMac and a full complement of really good software.

And my project is really a sound art project...the kind of stuff you might find in an art gallery rather than a movie house.

My basic problem is that the only way you can play back 6 channels of audio from my Mac is by using a converter with 6 analog audio outs, OR playing it back as Dolby Digital from the optical or digital out. But the Mac can't (so far as I know) take 6 tracks, convert it in real-time to Dolby Digital, and route it out as a digital signal.

Most inexpensive 5.1 domestic gear only takes the digital in, and doesn't offer discrete analog inputs. In fact, I already have one of those. I thought about cracking it open and seeing if I could wire up my own analog in's...but I'd likely just ruin the whole thing.

So unless there's a better idea here is what I'll likely do.

(1) Complete all the tracks.
(2) Make a good stereo mix and record that.
(3) Pan the tracks to the desired 5.1 locations keeping everything else the same.
(4) Record that as a 5.1 mix to disk.
(5) Encode that mix as Dolby Digital to disk.
(6) Play back that mix out as a digital signal into my home 5.1 system.

I won't be able to do the 5.1 mix in real-time...but for this "sound art" project that won't really be required...although the above is a bit of a hassle. But since I won't be manually panning in real-time, but rather just setting a level and a position and that's it, it should work OK. Maybe.

Galanter -- I read this recently -- maybe is of some help?
http://www.oreillynet.com/pub/a/oreilly ... -dvds.html

Maybe to make some clever things with pipes to make real-time encoding?

My friend did a Masters in music tech and spent most of his time on exactly this. If you give me some more details, like the program you're recording in and audio interface, I can ask him a few questions. My band got to make our first record for free at his school's studio, because he made like 4 different surround mixes of one of our tracks as part of a project experimenting with different surround sound theories for bands that normally wouldn't be mixed surround (read: shitty punk bands)

Hi guys and thanks for the help. The link is a good one, although I was familiar with much of it. The USB audio aggregate thing I didn't know about though. That's really useful for folks who have stereo converters and want to gang them up to make quad or 5.1 output.

My problem really isn't a highly technical one...it's really a how-can-I-do-this-with-what-I-happen-to-have-on-hand problem.

My Mac's fine. A recent vintage iMac with lots of good software...Logic, the full Final Cut suite including SoundTrack Pro, Reaktor, DVD Studio Pro...everything is fine there.

What I wanted to be able to do though was monitor 5.1 surround in real-time. I have a 5.1 (consumer) home theater system, but it only takes an optical input and not 6 individual line inputs.

So I would have to find a way to take, say, surround sound from Logic and then in real time encode it to Dolby 5.1 and take the optical output and plug that into my home theater system. And so far as I know you can't do that. You have to either have 6 line outs and a speaker system that can handle that, or you have to give up on real time, mix in stereo, burn it to DVD, and then play that back on my home theater system.

In short, I know how to do what I would like to do, but not without buying a 5.1 speaker setup that takes line ins. I even already have a USB 6 channel line out device.

What I really should do is shell out $1500-2000 for 3 more little Genelec monitors and a sub-woofer and be done with it.

Sorry for all the detail.

Why not get together whatever extra power amp/monitors you can find and wire those up instead of the surround amp? make the critical sound decisions on the good monitors, and whatever else you can find around the house should be a close enough idea of placement. There are real time dolby 5.1 converters out there i think, but they cost $$$.

galanter wrote:So I would have to find a way to take, say, surround sound from Logic and then in real time encode it to Dolby 5.1 and take the optical output and plug that into my home theater system.

Can logic stream output as multi-channel wav? The ffmpeg can then take this wav and convert to 5.1, yes? Then use another program to pipe to optical out.
Maybe this can be done with small latency as series of pipes?

hbc, yes this is more or less what I'm going to do. I'm going to make critical decisions with a pretty good stereo monitoring rig, and then listen to placement out of real time.

r, I hadn't thought of using pipes to send the audio from Logic to unix programs...not sure that will work...sort of assuming it won't. But I'll poke at it, and if it does work I'll report back here. Thanks!

Short progress report for anyone who might be following this.

I hooked up my consumer 5.1 speaker system to my iMac using the optical interface. The 5.1 system is actually better than I remember it. It's a Boston Acoustic something 6000....a pretty early unit that got good reviews at the time. Not as good as my Genelecs, but pretty good nevertheless.

I was able to play my test DVD on the iMac using the standard DVD player app, send the sound via optical, and surround worked as it should.

I'm a version behind with Logic and the various Final Cut programs...but I see no impediments to doing this project. Logic is ready to mix in 5.1, Compressor is ready to make AC-3 Dolby Digital from 6 channels of audio, and DVD Studio Pro is ready to take that and make a surround DVD.

(Note: The new Logic release has a ton of improvements, surround sound and otherwise. The "true" 5.1 reverb will likely push me to pay the $200 for the upgrade.)

Next step. I'm going to make my own test DVD to exercise all the 5.1 channels (maybe various tones and pink noise, maybe some cheesy circular panning) using Logic, Compressor, and DVD Studio Pro. If that all works, and it really should, I'm ready to actually make some pieces.

(This is going to be generative stuff...more about that later if folks are interested.)

Also this...I will have to make a DVD image to hear the 5.1 mixes, but I can just mount the image from hard disk and play it back from there. i.e. I shouldn't have to actually burn physical DVD discs to hear my 5.1 mixes.