Re: [microsound] Help: 5.1 Surround mixdown

[g d <rupanama@xxxxxxxxx>]

Bard,

Thanks for your reply, and I'd be interested to hear what your colleague has
to say about encoding plug-ins. Everything you said makes sense to me, but I
don't think I clearly described my problem:

When I bounce the audio tracks down in a 5.1 surround sound mix, I get two
stereo aiff files. As far as I can tell, these correspond to a typical 5.1
two-channel additive "reference downmix". Here is what the Dolby Labs
published about this mixdown:

[ 4.5 Downmixing
The performance of a multichannel system under the conditions of two-channel
playback should be tested using a reference downmix. Although the use of a
fixed
downmix may seem restricting, it covers the worst-case real-world scenarios
that may
be encountered.
In addition, time and budget may limit the ability to create a separate
stereo mix,
leaving the downmixed 5.1-channel as the only stereo option. In some
circumstances,
only a downmix is available (portable players, broadcasting, and so on);
therefore, it
is important to monitor the results while still in the studio. The equations
for the
reference downmix [10] are:
Lo = 1.00 L + 0.71 C + 0.71 Ls
Ro = 1.00 R + 0.71 C + 0.71 Rs ]

However, I am wondering what to do with this pair of stereo aiff reference
downmix files: do I mix them down again to get a single aiff file, or is
there a decoder that can use these two reference downmix files and playback
my recording?

Thanks for your help,
-greg

On Tue, Jul 1, 2008 at 11:18 PM, Bård Harazi Farbu <bardfarbu@xxxxxxxxx>
wrote:

> hi greg
>
> dolby suround is a suround system that is stereo compatible.  it used to be
> the standard for cinemas. it works in the way that signals embedded in the
> stereo mix that are out of phase are forced out of the suround channels -
> giving you the ability to "space things out". When you do your mix you
> encode it with hardware from dolby (i bet you can get pluins theese days,
> which will do the job for you - i can ask my coleage if your interested.)
> and you end up with a stereo signal. when the mix is played back,  you
> decode it (e.g. dvdplayers has the decoder  built in) and you get your
> suround mix
>
> when you mix 5.1 in logic you are mixing 6 discrete channels. this will
> never be stereo compatible - unless you convert it to dolby suround (which
> again i guess you can get plugins to do for you.)
>
>
> regards
> bård
>
>
>
> On Jul 2, 2008, at 12:45 AM, g d wrote:
>
>  Hello All,
>>
>> I'm attempting to mix down 15 tracks into Dolby 5.1 Surround Sound using
>> Logic Pro 7.2.3. The panning is all set and I can bounce the tracks, but
>> the
>> result of bouncing is two aiff files labled "[title]-L" and "[title]-R". I
>> found a Dolby Labs publication that descibes these as the two-channel
>> mix-down of a 5.1 format. However, the publication says that these can be
>> decoded into 5.1 audio: how does this work?
>>
>> My question is this: are these two audio files all that is needed to
>> playback my composition in 5.1 Surround? Do I have to make a final mix of
>> the two files to get one 5.1 compatible audio file, if so how do I do
>> that?
>>
>> Obviously, this is my first attempt at Surround Sound mixing. Any advice
>> is
>> greatly appreciated.
>>
>> Thanks,
>> -greg d.
>>
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: microsound-unsubscribe@xxxxxxxxxxxxx
> For additional commands, e-mail: microsound-help@xxxxxxxxxxxxx
> website: http://www.microsound.org
>
>