Dolby Surround Tools Help!

[audiopostmixer]

Hi all,

Long time reader, first time poster. I am having an issue with my Dolby Decoder plug and wanted to see if anybody has the same problem or suggestions.

When I send a stereo signal into the encoder to create an Lt/Rt file, I can see it on the meters as only a Left/Right Signal. Now, when it is decoded, it plays back as left/right and surround.

Anybody else ever experience this?

Thanks for your help!

[JKD99]

Hi there,
Don't worry, it's perfectly normal, and exactly the reason that we always caution people doing plain-stereo mixes that will be played through a Dolby Decoder in a theater: some content will always be sent to the surrounds from a plain-stereo mix, especially reverbs and other out-of-phase material.
There's others on this forum who can 'splain it in more technical terms, but the main thing is that it's just how the decoder works.

hope this helps, good luck!

Joe

[audiopostmixer]

Thanks for the info!

I assume its all phase related. I'm only sending a stereo music track, which is left/right in my 5.1 discreet track, and left/right/surround on my decoded LCRS track.

Any tips on how to adjust the signal, or do I just have to live with it?

Thanks again!

[audiopostmixer]

Thanks for the info!

I assume its all phase related. I'm only sending a stereo music track, which is left/right in my 5.1 discreet track, and left/right/surround on my decoded LCRS track.

Any tips on how to adjust the signal, or do I just have to live with it?

Thanks again!

[audiopostmixer]

I found this useful info on the Dolby site if anyone is interested.

Dealing with Stereo Sources
Stereo sources, as well as premixed matrix-encoded elements within the mix, will be correctly
processed by the decoder. These elements are generally assigned to Left and Right channels.
The preencoded element will be decoded as expected, and a phenomenon known as “magic
surround” will create the soundfield from the stereo element.

Dolby Pro Logic II was specifically designed to take stereo elements and create surround sound-
fields from them in a pleasing way. Exactly how the elements are decoded will be affected by other
elements within the mix. Agiven stereo element may sound fine by itself, but have problems when
other elements are added to the mix. In these cases, tweaking the mix to compensate for the
added elements and achieve the desired results may be required. This is also true of preencoded
elements. While it is common practice to premix elements for a large or complex mix and utilize
the surround encoder in the process, it is mandatory for the mixer to listen to the combined mix
through a decoder with all of the elements present in the mix. Any change in levels, or additions
and subtractions of signals in the mix, will affect how the decoder handles the signals.
Occasionally, a stereo source may contain more surround information than is desired when it is
decoded. This is particularly true of stereo keyboards and other devices that manipulate
waveforms to achieve their signature sounds. In these instances, simply panning the stereo
element away from hard left and right and bringing it toward the center will compensate for this
problem. It usually doesn’t take much panning to fix the problem. Pots originally panned hard left
and right probably won’t need to move past the 9 and 3 o’clock positions to produce pleasing
results while maintaining the stereo image originally intended. This is further proof that mixes need
to be monitored through a decoder to ensure that problems do not exist.