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5.1 layoff. Dual Mono VS Stereo outputs
Hey guys, we’re laying off a 5.1 mix to D5 for the first time and Im confused about the definition of Dual Mono. We just want regular mono correct? What would be the proper settings for a 5.1 layoff in FCP?
We’re planning on:
1. Left
2. Right
3. Center
4. LFE
5. L Surround
6. R Surround
7 + 8 StereoFC only allows you to choose dual mono or stereo for audio outputs. I know I can map individual channels if I set up as dual mono but should I keep it at its default of -3db?
Thanks,
Chris -
8 Replies
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So i’ve been researching a bit more online and I’ve found this helpful article:
https://www.kenstone.net/fcp_homepage/5-1_surround_sound_FCS2.html
Seems straight forward enough but Im still confused as to when/why I should set some channels to -3? He shows two examples of how you can set up your outputs but Im not quite clear why hes set them up as such.
In the examples he shows, channels 5&6 (Left surround and right Surround) are always set to -3 whether you use stereo or dual mono. But channels 1&2 are set 0 when in stereo and -3 when in dual mono. To make matters worse, he says channels 1&2 are L Surround and R Surround which is incorrect yes?
Very confused.
Thanks,
Emery -
There are many “standards” for track config in 5.1 so it is important to know what is required by distributors or broadcasters. Whatever you choose, please label the tracks on the output tape clearly.
Anything that changes levels will make your sound post people very annoyed. If you are confused about dual mono, I would recommend keeping everything as stereo channels and make sure your levels are unity and everything is panned hard left/right.
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The only reason why you would set the channels to -3 is if you were mixing beforehand (in stereo) and now you’re applying that mix to a dual mono layoff – the -3 allows any material that was in both channels to sum to 0dB. In other words, if you aren’t doing the actual mix (in FCP) and are just adding someone’s mix to your cut, don’t use -3. Stereo output is fine, provided you assign the audio track outputs correctly. For me, I don’t bother – just set up the sequence as 8 outputs, dual mono, 0dB downmix. When you add the eight channel mix, each audio track will feed direct to the corresponding output. The proper order for layoff (according to AES and many other authorities) is L/R/C/LFE/Ls/Rs/Lt/Rt (where Lt/Rt is either a Pro Logic encoded stereo downmix or a separate stereo mix). It is a great idea to provide this channel assignment in your slate and on the tape label, but even if you didn’t most will expect when they see eight channels of audio that this will be the order. Hope that’s helpful.
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Hey Mark thats very helpful indeed! What I read in the manual was the mix level in the audio output is for your down mix only so it shouldn’t bare any relevance to what Im sending out of the SDI correct? The default 5.1 setup in Final Cut is:
Ch 1&2 Stereo 0db downmix
Ch 3 Mono -3db downmix
Ch 4 Mono ‘off’ downmix
Ch 5&6 Stereo -3db downmixI kept it at the defaults and made sure Ch 1&2 and Ch 5&6 were set as stereo pairs in the timeline. Being that the downmix is only for monitoring purposes, this setup would work fine for laying off 5.1 to D5 correct? Each channel is mapped appropriately and in the order you specified.
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Chris – that sounds right. I am mostly an audio guy, working in Pro Tools, so I’ve been reluctant to do any “mixing” or anything like it in FCP. I usually create master mix files in Pro Tools and then drop them onto an FCP sequence to layoff with the edit, so I haven’t had the use for the ‘downmix’ feature in FCP. Being always wary of any level change to my mixes, I’ve kept everything I could find at 0dB (unity gain / no change). The easy way you’ll be able to tell if it’s changing the level on output is to drop some 1kHz tone from the Bars and Tone NTSC onto all of your audio tracks and play them out with your configuration. If it shows up at the deck as all even, then you know you’re good to go. That would be my failsafe method to make sure FCP isn’t dropping the actual discrete output levels.
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[Chris Sanderson] “Being that the downmix is only for monitoring purposes, this setup would work fine for laying off 5.1 to D5 correct?”
No. Changing levels affects the SDI output. Map for six or 8 channels output, make all channels stereo and patch 1&2 to 1&2 output, 3&4 to 3&4 output and 5&6 to 5&6 output. Set all channels to 0 and pan hard left right.
Now you are set to output the channels at unity and discreet. The FCP default is not correct for output to tape.
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Thanks for the advice guys. Michael, that doesn’t seem quite right though. I just did a test as Mark suggested using Final Cuts tone generator. The ‘mix down’ level in the audio tab of the sequence settings has no effect on the levels output through SDI. If you turn on ‘mix down’ in the Audio Mixer tool then yes it does have an effect but then you are also only getting a stereo output.
Also, channels 3 and 4 (center and low frequency) seem like they really should be mono as they are definitely not stereo. All the research ive done points to the conclusion that final cuts default 5.1 sequence preset will work fine as long as you set Left and Right as a stereo pair and your Ls,Rs also as a stereo pair in the timeline. Otherwise keeping everything at dual mono will also work as Mark pointed out.
Really appreciate the input guys.
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Hi.
The answer to this question is likely in this thread but I must admit some of this confuses me a bit.
Here’s my specific question. Maybe there is an answer simple enough for a guy like me.
I have two external monitors I’d like to set up to my IMac. I’d like to be able to listen to my FC project in mono as it will be broadcast that way.
I can connect to the computer’s mini-jack with a selection of cables that will produce effective mono (stereo will go to both speakers), but it’s a fairly expensive arrangement. I could save $45.00 with another cable combination that would produce stereo in my speakers. If I could get FC to output in mono I could use these cables, get the mono I want and save myself some money.
Is there any way; i.e. a relatively easy way to set up FC to do this? Either such that the whole project outputs in mono, or at least such that individual sequences could be set up so?
Thanks.
John
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