How to make Dolby Digital surround

[videofreak]

Hi,

Who can help me in finding information on how to make Dolby Surround. What I want to do is play the original sound of my films in the front and music in the back.

Who can help?


Thanks for you reply

Peter

[BJ_M]

are you wanting to convert a 2ch to 5:1 ? or you want to mix original tracks to 5:1 ?

ACID is very good for a cheap solution to do a 5:1 mix as it supports it native with proper sound placment in 2d - then compress to ac3 with one of the many compressors now avaible - even free .

better mix downs to 5:1 are found w/ Protools and Nuendo surround edition.

the you can get into 3D sound placement with solutions like Timax 3D (what i use along with Nuendo as front end, but this is a hardware solution).

if you want to convert a 2ch to 5:1 (like from a dvd rip to svcd) .. well, all you will get is all the audio playing out of all the speakers .. generally you would take FL and FR and add 20ms delay and feed these to the rear surrounds and then sum the fronts and apply a crossover at 120hz 18dB per octive 4th order LW and feed that to the LFE (ussually giveing a bit of a hump to around (+4dB) 110 and +3 @80Hz -- depending on source, then rolloff below 20Hz ..
but this is NOT the original 5: 1 mix which you would not be able to re-create.

[hp_lovecraft]

If you will settle with plan old dolby surround, then you can do what you want to do with a plan stereo track, and any basic wav editor.

I just did something similar. I was making a home movie VCD, and I wanted music in the front, and voices in the rear speakers using Dolby-Prologic.

ProLogic is just a stereo track. It sounds just like a stereo track through a stereo system, but a surround system can decode it to send audio to the rear speakers (and also center speakers).

The prologic decoder will send audio to the rear speakers if the exact same audio is in both channels, except one channel is 'out of phase'.
So, for me, I just split the audio onto 2 tracks, and then reversed the phase on one track (most wav editors can do this). Thats it. If played through a surround receiver, the audio will come out the rear.

Music is more complicated. The rear prologic speakers are mono, so you would have to convert the music to mono first, then split, and change phase.

Technically, it is not a true surround track because it lacks flags, but works perfectly as a stereo track (PCM,DOLBY,MPEG,etc).

Nick

[Cornucopia]

Let me get this right--

You have the original film soundtrack in stereo ( L,R ) or in 3 of the 5.1 surround channels ( L,C,R ) and you got stereo music ( L,R ).
If all you want to do is make a new 5.1 AC-3 encoding and you already have something like SF SoftEncode, it's just a matter of :
1. make sure all your files are pcm/wav to start with
2. load them into the program
3. designate which files/channels get output to which speakers
4. encode to AC-3

That's it. Oh, you MAY have to make them all the same length. It or the authoring prog might bitch at you otherwise.

Just one point of clarification--not meaning to start anything.
Technically, Surround isn't 3D. Not adding in reverberant sound from the room itself...
Mono (1 Channel) is 0D
Stereo (2 Channels-poss 3) is 1D
Surround (4...7.1 Channels) is 2D
3D includes HEIGHT (above, below) e.g. the AMS/Calrec soundfield mic system. Pretty rare though. (Binaural might be includable here)
Sorry to get esoteric on your ass.

Happy encoding!

Scott

[SingSing]

If you will settle with plan old dolby surround, then you can do what you want to do with a plan stereo track, and any basic wav editor.The prologic decoder will send audio to the rear speakers if the exact same audio is in both channels, except one channel is 'out of phase'.
So, for me, I just split the audio onto 2 tracks, and then reversed the phase on one track (most wav editors can do this). Thats it. If played through a surround receiver, the audio will come out the rear.
Nick

It sounds like ( punt intended ) that if the listener move near to one of the front speaker, that you will be able to hear the sound from the "surround channel", since cancellation will not work well off-center.

[BJ_M]

Let me get this right--

You have the original film soundtrack in stereo ( L,R ) or in 3 of the 5.1 surround channels ( L,C,R ) and you got stereo music ( L,R ).
If all you want to do is make a new 5.1 AC-3 encoding and you already have something like SF SoftEncode, it's just a matter of :
1. make sure all your files are pcm/wav to start with
2. load them into the program
3. designate which files/channels get output to which speakers
4. encode to AC-3

That's it. Oh, you MAY have to make them all the same length. It or the authoring prog might bitch at you otherwise.

Just one point of clarification--not meaning to start anything.
Technically, Surround isn't 3D. Not adding in reverberant sound from the room itself...
Mono (1 Channel) is 0D
Stereo (2 Channels-poss 3) is 1D
Surround (4...7.1 Channels) is 2D
3D includes HEIGHT (above, below) e.g. the AMS/Calrec soundfield mic system. Pretty rare though. (Binaural might be includable here)
Sorry to get esoteric on your ass.

Happy encoding!

Scott

yes -- as i stated , all was in 2D except i mix in 3D with the Timax system which IS true 3D

[Cornucopia]

@BJ_M: Cool!

I'll check Google, but do you have a site for that?
I assume it's tied into a Nuendo setup. I've got ProTools, which I'm more than satisfied for what I'm using it now. But I've followed Binaural, Surround, and 3DAudio for a while (off and on). Sounds like I need to update.

Thanks,

Scott

[BJ_M]

@BJ_M: Cool! :D

I'll check Google, but do you have a site for that?
I assume it's tied into a Nuendo setup. I've got ProTools, which I'm more than satisfied for what I'm using it now. But I've followed Binaural, Surround, and 3DAudio for a while (off and on). Sounds like I need to update.

Thanks,

Scott

Timax is an outboard hardware box with its own computer system controlling it -- 8 in 8 out .. 8 in fed by Nuendo .. , 8 out to ADAT HD24 or routed back in again ..
http://www.outboard.co.uk/pages/timax.htm
http://www.livesoundint.com/archives/sepoct2001/alweener3.html

[videofreak]

Thanks guys. It helped a bit. I am even more confused now What would be the best tool to get in order to gain experience with the subject?

[Heavensent]

if you want dolby digital ac - 3 (5.1)
then you need to use Sonic Foundry - Soft Encode
as some one edvised on a previous post.
you will be able to make this thing work.
BUT - you will get audio that will take up a lot of space (like wav files).
so you will not be able to fit the video + audio on one cd.

i think something like multichannel mpeg whould be what you need
but i dont know if you can get good information about that,
i have tried but didnt find something i can use.

[BJ_M]

ac3 files are pretty small -- dont take much room at all .. lot of compression there