Bobbo (Audio Design and Recording) asked a question.
Stereo Downmix problem
When I switch the renderer to 2.0 output, I cant hear the effects of the change in downmix parameters on a live mix.
When I listen to the live stereo re-render - I can hear my settings, but not entirely as I expected.
For example, when I set surround and height trims to 0, I hear the top front and the side surrounds folding to stereo at 0, but the rear tops and the rear surrounds seem to stay at -3.
How can I get a fold down with everything set to 0, (except centre at -3?)
When I listen to the live stereo re-render - I can hear my settings, but not entirely as I expected.
For example, when I set surround and height trims to 0, I hear the top front and the side surrounds folding to stereo at 0, but the rear tops and the rear surrounds seem to stay at -3.
How can I get a fold down with everything set to 0, (except centre at -3?)
Thanks, Adam
Spatial coding is off - Just double checked.
So - with it on, I'm getting the Top Front and the Side surrounds evenly. (with a setting of -3)
But the Top Rear and the Surround Rear are both about -3 down.
With a trim setting of 0, (as requested by Universal) I get the side surrounds too loud, and the rears again at -3 relative to the front.
That's not really a smooth fold down.
Is there a way to get a re-render with the rears at 0 and side surrounds all at 0?
I think I might be doing something stupid, but I cant work it out!
thanks for your help.
b
Bob
Ok. Yeah you need to have Spatial Coding emulation on when auditioning the re-renders. Does the spec dictate the 5.1 downmix mode? From what you are describing this sounds like the 5.1 downmix is set to Direct Render. This is upstream from the downmix to 2.0 so can have an impact. If the delivery spec doesn't mandate a downmix mode you might want to try changing this Direct Render with Room Balance which would help even out the difference you are hearing between the side and rear surrounds. If that isn't an option the Front/back balance controls can also be used to push more energy towards the rear surround.
Best,
Adam
I'm testing with panning pink noise around.
The front back balance seems to have more effect on the front / side balance.
Direct Render mode creates a phantom side surround in 5.1. Any content panned to the side surround (or render to the side surround from the top center) is equally in the 5.1 fronts and rears so the downmix to 2.0 is pretty neutral. Content panned toward the rear surrounds is going to be dropped 3db when summed with the front. So what you are describing sound pretty expected really and is default behavior to avoid excessive build up and preserve vocal intelligibility (assuming there are vocals). Apologies that I didn't glom onto that from the start.
Unfortunately If you think this has a negative impact on the 2.0 mix your options are to tweak the whole mix (probably not what you want to do) or render out the 5.1 and goose the rears prior to creating a fold down of your own.
Adam
That's great info and makes sense - I understand whats going on now!
Really appreciate the prompt guidance.
Bob,