Folding 5.1 to Stereo

[chuckmtk]

Hello all! Since I am a beginner in the 5.1 surround game........I was wondering if anyone could provide me with information and/or the steps involved to fold a 5.1 surround mix into a stereo mix! Any help would be greatly appreciated!!

Many thanks!!
Chuck

[The Chinese]

Hello all! Since I am a beginner in the 5.1 surround game........I was wondering if anyone could provide me with information and/or the steps involved to fold a 5.1 surround mix into a stereo mix! Any help would be greatly appreciated!!

Many thanks!!
Chuck

Chuck-

Here's what I suggest-

Make it an LtRt stereo compatible mix. To do this, youwill need a Dolby SEU4 or Dolby surround Tools ProTools Software and a TDM system.

A) L-C-R into the L-C-R inputs of the SEU4 or DST at unity gain.
B)Take your surrounds and sum them to mono at -0dB. (this means each surround channel is at -6dB) This then goes to the surround input of the SEU4 or DST.
C)Take your LFE and pull it down to -9dB. This signal then goes to the L-C-R inputs of the SEU4 or DST.

This is the standard Dolby folddown. You can alter it for sonic reasons if you wish, the most common way is to sum the surrounds at -3dB each.

If you don't have DST, you can download a demo from Digidesign that will work for 30days.

Hope this helps-

-Todd A.

[CCash]

Hi Todd. Hope you're doing well. Just curious, this is from the Dubly 5.1 production Guide. A little long, but note that they say "discarding the LFE".
_________
"There are many consumers who will listen to Dolby Digital sources such as DVD or
DTV without having a full 5.1-channel Dolby Digital playback system. These
consumers will hear the two-channel analog or PCM outputs of their DVD players or
DTV set-top boxes through existing stereo or Dolby Surround Pro Logic systems. All
DVD-video players and DTV set-top boxes have the ability to create and deliver a
Dolby Surround compatible or stereo downmix from the two-channel analog or PCM
outputs. The DP562 Professional Reference Decoder can simulate what the consumer
will hear while listening in these modes.

Example 1: Using a properly calibrated 5.1-channel monitoring system (incorporating
appropriate bass management) set the DP562 to Dolby Digital and Full. In this
configuration, a 5.1-channel bitstream will reproduce all channels as a consumer with a
Dolby Digital 5.1-channel system will hear it. Pressing Pro Logic on the DP562
downmixes the five main channels (discarding the LFE channel) to a Dolby Surround-
compatible bitstream. The downmix is then Dolby Surround Pro Logic decoded
resulting in Left, Center, Right, and mono Surround channels at the outputs. Monitoring
in this mode simulates how a consumer will hear the 5.1-channel bitstream when
downmixed and then reproduced through a Dolby Surround Pro Logic system."
_______

Folding the LFE into the LCR is one of many ways I've heard to do the foldown and seems reasonable, but are you sure this is the Dolby way? Not being confrontational... just want to be informed.

Curt

[The Chinese]

Curt-

There are a bunch of variations on this theme...yes, some call for elimination of the LFE track. I was under the impression from my verbal conversations w/ Dolby that the way I posted above was standard...perhaps it's and "Industry" standard only. Ultimately, I'd say keep the LFE, so lng as it is not creating problems in your downmix, either level-wise or steering-wise. YMMV.


-todd A.