Hi. This time, I wanted to write and share a template I made quite some time back, in Pro Tools for a downmix based on a 1992 proposition put forth by Michael Gerzon at AES in San Francisco. The idea behind this was to have a bit more width to the stereo mixdown compared to the standard one. Now, this is all purely experimental on my end and it seems to work very well on headphones as well. But I would invite you all to download this and try it out to experiment for your own conclusions. After all, a hive mind is always better than one!
The Mixdown Method
The method employed is as follows. (You can find the reference for this in Spacial Audio – Francis Rumsey) Gerzon proposed an alternative downmix formula based on 5.0 tracks:
L0 = 0.8536L + 0.5C – 0.1464R + 0.3536k(LS + RS) + 0.3536k2(LS – RS)
R0 = -0.1464L + 0.5C + 0.8536R + 0.3536k(LS + RS) – 0.3536k2(LS – RS)
where the suggested k and k2 value is
k = 0.5
k2 = 1.1314
If you convert that to fader levels for Pro Tools, it would become:
L0 = -.68dBL + -3dBC + phase-8.35dBR+ -4.52*k*dB(Ls+Rs) + -4.52*k2*(Ls-Rs)
R0 = phase-8.35dBL + -3dbC + -.68dBR + -4.52*k*dB(Ls+Rs) +p( -4.52*k2*(Ls-Rs))
Note: I am open to corrections if you find any fault.
The Pro Tools Session
In the template, I have kept the phase inverted signal to 0 rather than -8.3dB just because it felt good to listen to that. But please experiment with that for Mono compatibility as well. I also added the LFE at -12 dB to taste. The way the Template is set up is the top track is where you drop your 5.1 audio. This then goes through the matrix as you can see. You can choose to monitor either the Gerzon version or the regular downmix by alternately muting the 5.1 and the MixDownRegular. The 5.1 track when unmuted will give you the Gerzon version and when muted and the aux below is unmuted will give you the regular downmix.
Additionally, the two masters for Ls+Rs and Ls-Rs are at -2.2 dB. Changing that will change the spacial width of the surrounds that are added into the downmix.
Happy experimenting!
Download here:
Gerzon 5.1 Downmix Template
–FM
Thanks for sharing
Hi Sreejesh. This is Devarsi, film and music journalist with Scroll.in. I would like to interview you regarding The Mastering Project. I have messaged you on FB as well. Please let me know how we can go forward.
Hey Sreejesh,
I accidentally found your blog a few days ago,and now i have read all your post and i have to say they are very helpful and inspiring. Actually,i have many question on the basic 5.1 mix that i don’t even know where to start, and what confusing me most is the routing and tracks build as well as the basic plug-in use in a 5.1 final mix session using PROTOOLS, can i bother you to give a template that you use in your works or something, i really want to learn. However if it’s inconvenient for you to give the template ,can you tell me your e-mail or Facebook so I can contact you .My e-mail is 1013065178@qq.com
Thanks a lot, sincerely