5.1 Surround sound

[Apollo]

Right here's the story.

the company I work for do all of VT Groups conferences and events.. They are a very ambitious company and the main person we deal with is always pushing for something truly memorable at each large event..
In March they are having their BIG event of the year where all the Directors, and Heads of management meet up...

This is a fun event, and they are turning the room into a "Batcave".. lol. I wont go into the specifics of the room size etc as that doesn't matter.. (it's a big room though).

Anyway, as their "finale" piece for the night, they are basically ripping off the Batman film(s) and making their own.. However, they want it in 5.1

How would we do it? We are basically talking a Cinema sound-system, we will have a true 16:9 rear projection set into the "batcave" - lol that still tickles me.

Anyway, is there a specific unit(s) for 5.1? What will we need...?? We've got monitors and all that malarkey.. but I cannot seem to figure out how we will do it??
Mainly because the presenters for the night will be miked up etc etc.. so will we need 2 sound systems? That's the only way I can see of going about it, a dedicated 5.1 system, and a seperate system for the presenters??

Help Please!!

Josh

[Simon Ryder]

I presume you want to create a 5.1 mix rather than just playback an existing mix.

Tricky.
What you need is a Dolby 5.1 encoder. Lovely bits of kit and VERY expensive. Or better yet an Ambisonics rig with an operator. VERY VERY expensive.

Cheap way is to use a 4 or preferably 8 bus console with a centre channel (GB4 etc). This will give you LC&R. Use a pair of the busses to output to the rear channels. Wire your subs up to an Aux.
You can then route you reverb returns and other effect returns to L,R,RL&RR. This will give you a surround ambience. Any principal channel that you want in the rear speakers as well as any of the front three will need to be run into the desk on 2 channels using a splitter (y split cables are very easy to make but if using phantom power you will need to get transformer splitters) If for example we do this to the lead vocal bringing him in on channels 23 & 24, then I would route 23 to centre or L&R and use the pan pots to creat the front image. 24 would be routed to busses 7&8 which would output to the rears. Using the pan on 24 I could create a stereo fiels between RL&RR and using the fader can move the image from front to back in the sound field.
Voila surround panning between 5 speakers! Use your Aux fed sub to dial in the amount of low end you want on that source.

Disadvantages - your channel count will be high. If you normally use 16 channels, you will need a 32 channel board to do this.

Other main disadvantage - very few of your audience will be in the correct position to hear the surround mix. Listener positionin is even more critical for surround than it is for stereo. (There is a very good reason that most pro engineers mix in mono - stereo system, mono mix)

This is why for large scale surround sound most people use Ambisonics which is not so position critica. Ambisonics relies on identical stacks (minimum of four, can go up to 32 way) placed equidistance apart. You also need a sound field mic and the encoder.

Good luck,
Simon

[Rick Sarson]

YoHo Captain,

What you need is a bit of kit called TiMax. I did the self same thing as you, ie played the clients' 5.1 program at a conference. Because of the way it works it actually improves the "sweet spot" of the 5.1 and you do not need to use two seperate sound systems, just add the rears and think hard about speaker positioning. You do not need a decoder, just a DVD player with the full set of outputs. Also you can move sounds about in real time. Go to www.outboard.co.uk to have a look. Delta Sound have one, as do Dimension Audio and Blitz. And no, I don't work for Outboard!

[Smifis]

Hmmmm... sounds like a fun company.

ok normally it isn't actually recorded in 5.1 surround sound at all!
it is done in an editing program like adobe premier.

there are many tutorials on the web on how to do this and i wont go into much detail here but i will help if you give me a pm on www.frozenhaddock.co.uk as i am normally on there.