MIX CONVERTER level settings?

Can anyone recommend the best Center, LF, & Surround level settings to use in Mix Convert when mixing a 5.1 film while using this converter to monitor it (folded down) to Stereo? It’s brilliant that Nuendo allows you to create a complex 5.1 mix, and with this Mix Converter plugin inserted across the main 5.1 output bus, it enables you to hear all the channels to at lease balance them while guessing how the 5.1 space will feel. The big question is do you set the above faders to unity gain (0db) or use the default settings which lower the C and S and LF channels considerably by different amounts? You would think that by doing that you’d be pushing too much energy into those attenuated channels.

Other people probably have more experience with this than I do, but I found the ‘default’ downmix to be good. The Direct Routing outputs have a default downmix preset applied to them, so following that for the “mix converter” makes it all predictable and you won’t run into a situation where some fold-downs sound different than others.

Automatic Downmixing (steinberg.help)

Mattia, Thanks for that encouragement. Would be good if their default works. I also noted that there is an overal loss of level through the Mix Converter of 12db. I am guessing that Steinberg are guessing that’s a reasonable drop to cover a build up of signals distributed across the 5.1 matrix. I’ve raised the output 10db (not input!) and will see how it develops over the coarse of a mix later today. Ta, Stav

What signal did you measure, and how and where did you measure it?

The most recent surround mixes I’ve done (last week) have had stereo and 5.1 mixes within about 0.5-0.7dB of each other, using standard loudness metering.

Here is my signal path that revealed this loss.

  1. Insert tone generator into a mono track -
    set to 440hz - generator gain set to -11. Pan Front Centre.
  2. set tone channel fader to unity. Mix bus will read -14db ppm.
    (or send tone from any channel il it reads -14db on master bus)
  3. insert Mix Converter with default levels and signal drops 12db.

I’ve tried different signal flows to provide both Stereo & 5.1. Not sure which is better. Sounds like yours is way better. My first approach was to create a 5.1 Master (final output) bus. All tracks eventually feed this. You can meter all 6 final channels easily. THEN insert Mix Converter (MC) into that 5.1 Master bus - set its output to Stereo. This way I monitor all folded down to Stereo. However the render from this bus, in that mode, creates a 6 channel interleaved file with the stereo mix on ch 1+2 (not a 2-ch stereo file). To overcome this I created a Stereo group (for rendering later) fed by Aux sends of the various 5.1 sub groups. Rather messy and flawed.

My second, and most recent, attempt was to do this backwards by having one Stereo Master output bus for monitoring and renderng the fold down but have 5.1 channels and 5.1 Groups along the way. So every channels feeds a 5.1 Group which I can render seprately (with MC bypassed). That same group feeds, via MC, the main Stereo Output. That’s where I’m at now. Bypassing the MC or switching it on creates this large volume discrepancy.

This should provide you with a host of elements I’ve got completely wrong:) Ta, Stav

Do you burn the 5.1 simultaneously with Stereo - or as a separate Render?

I don’t really see a reason why you should see a 12dB drop. That sounds like something’s wrong. Also, I would probably just skip the PPM meter and stick to sample and true peak plus loudness metering (BS.1770-1/2/3).

You should have the widest used channel count as your main mix. So definitely don’t set it up so you have a main stereo output and then upmix, you need to have a a 5.1 surround output as your main. This is in the “Audio Connections” “Outputs” tab only. Set that to “not connected”.

Then - in addition to that - create all the outputs that correspond to the final items you need exported, meaning full mix and stems. One for each, stereo and/or surround. Don’t connect them to anything either.

There you’ll have your full stereo and full surround mix and you can use them as monitor sources in Control Room and that’s how you monitor both formats.

To feed the stereo output a correct mix I would just use direct routing to get there, no need to make it fancy. So if you for example have three groups feeding your full master surround output mix - say Dialog, Music and Effects - then in addition to setting their outputs to that 5.1 mix output (not the “main”) you also add direct outs for each to the stereo mix output. There’s your automatic fold down. You now have two separate outputs receiving their own mix. Monitor in Control Room.

If you want more control over the stereo path then you “move up” the fold down from the output stage to the group stage and have your final 5.1 DME groups feed individual 2.0 DME groups which then feed the stereo output. That way if you feel your effects folded down a tad loud you can grab the fader of that group and lower it.

Obviously any stems and submix delivery specs will determine how you do this. If you need to supply dipped or undipped stems then you’ll just have to figure out where to do that in the chain.

I don’t think any of this is messy or flawed, it’s pretty standard practice and there aren’t that many more convenient ways around it.

Simultaneously. I set it up so I can output everything I need in one pass. Full mix, M&E, MED, individual stems, censored and uncensored… all of it in one go in both 2.0 and 5.1.

That is all most helpful. I got a few questions but so you don’t think I’m a complete dill, here is my mix room:


  1. you wrote: 'To feed the stereo output a correct mix I’d use direct routing to get there, no need to make it fancy.
  • I like the ‘nothing fancy’ part. How do you patch direct routing from the final 5.1 to a renderable stereo bus? A screen shot might help. If you mean from all the stem groups that won’t include the sub and you really want it from the final / main 5.1 to be sure you got everything.
  1. slight confusion here …'if for example you have 3 groups feeding your full master 5.1 output mix - (Dialog, Music, Effects) [yes I do] - then in addition to setting their outputs to that 5.1 mix output (not the ‘main’) you also add direct outs for each to the stereo mix output.
  • I thought the routing module allows on one destination unless you use auxes. Does that mean you don’t use the Mix Converter? How do you do Direct Outs? So no MC? or where does MC insert.

You’re way ahead of me and this helpful direction is muchly appreciated.
Ta, Stav
PS you can always contact me through the contact page of that site.

oops I didn’t mean for the sales pitch to appear in this thread. This site grabbed that. I just thought you’d like to see the photo on that page of a unique console. studio stav. com / services

You might be missing the above. Right-click where it says “DIRECT” in the mixer and then enable “Summing Mode”. It’s a poor name for allowing multiple outputs from the “Direct” section.

That may answer several of your questions… (?)

I’ll throw out one additional note for you as well - the pan law settings apply to the first direct output and to sends, but not to direct outs 2-8. Those last ones always get the built-in automatic downmix that I linked to. This is another reason for setting pan law accordingly so that if you choose to swap between sends and direct outs for whatever reason (pre-/post-fader stems for example) your downmix will (should) always be the same regardless of if it’s coming from a send / output 1 or outputs 2-8.

No MC. It would have been selected as a panner, but now that I think about it it’s actually sort of interesting that it exists there since there’s downmixing anyway even if you just use the default VST Multipanner.

5.1 Block Diag 01.pdf (111.2 KB)
Here is a block diagram of where I’m up to so far. I’ve kept the Master out to 5.1. Got 5.1 sub groups for Music, Dialogue, etc. They route to Master out and also use Aux sents to feed a separate Stereo Group. This way I can Render only the Stereo or the Master 5.1. Am not too concerned about being able to render both simultaneously but do need (if you think this patch is correct) to monitor them easily and know where to insert Mix Converter plug if needed. Thanks for hangin in there. Stav (did you see the Smart Console?)

Understood. I generally prefer using the Direct Outs, but you could certainly use Sends instead.