Converting mono to stereo audio tracks in cubase 12 and pan plugins

I have become rather partial to using pan plugins like boz pan knob 2. on mono source files, these need a stereo channel to work.

I know cubase 13 has the facility to easily convert mono to stereo and this is great, but the GUI is too painful for me old eyes. so, in cubase 12, it seems you have 2 options. 1 - create a stereo track and copy and paste all the audio from the mono track. 2 - route the mono track to a stereo group channel.

if you do the former, what is cubase actually doing and how is it processing that mono source? comparing a compressors action on both the original mono channel and the new stereo channel, I see that the gain reduction meters are showing less compression on the stereo channel. which suggests that there’s less level coming thru the channel. presumably it is just routing the mono source material 100% thru both sides of the stereo channel? if so why does the level appear to be different?

Don’t know for sure, but I’d suspect the Pan Law

If you send your mono signal to your 2 stereo channels, it will normally compensate -3b (or your pan law setting in project setup-> pan law).

ok digging in to this a bit more.

channel A - mono audio file playing back as a mono channel in cubase mixer
channel B - mono audio file playing back as a stereo channel in cubase mixer
all audio parts were copied and pasted across. project pan law is 4.5.

channel B will show 4.5db lower on the channel meter, but will sound the same volume as channel A. however both will appear the same level on the stereo out meter. ? even tho they sound the same volume, put a compressor on both channels and channel B comp will be showing less GR. to get both channels behaving the same, you have to add 4.5db gain at the beginning of channel B and -4.5db as last insert. THEN the comps will be hitting the same and the audio will sound the same volume (even tho the meters on the individual channels don’t agree.

if you pan both hard left or right, channel B is 4.5db lower in volume, despite sounding the same volume when panned centrally. put boz pan knob 2 on channel B set to 4.5db pan law, panning from within pan knob 2 now results in same apparent volume.

confusing much? obviously this is related in some way to the pan law, but I can’t for the life of me work out in what way?

Cant try it atm but it sounds normal. Pan Law means that your MID signal will be (-4.5dB) attenuated. So there are different options now. You created a mono channel which is routed to the stereo out, you should see “both” meters on your mono channel right? If you routed it to lets say left out only, you have only one meter visible (as if you hard panned it). Lets say your signal is a sinus 0dB. In the first case you would see -4.5dB on the channel meter (because the mid is compensated to -4.5dB). In the 2nd case you would see 0dB (or if you hard panned the first case) because this is your original signal level. If you drag your mono signal to a stereo channel now exactly the same happens (signal will be send to both stereo channels). About the compressor - you cant compare that because in case one its a mono compressor in case 2 a stereo. To be comparable you should use it on the stereo out for both channels. Hope that makes sense…

hi david thanks for your input.

re compressor action - the only way to get the same amount of GR, AND for it to audibly sound the same level, is to add 4.5db gain at first insert and minus 4.5db as last insert. I don’t understand why this is to be honest. a quirk of the cubase coding I guess.

a further problem appears to be the panning issue. if you want a mono track to be a stereo channel, the panning on the stereo channel, whether its a stereo group with the original mono channel routed to it, or a new stereo channel with all the data copied and pasted across, will not behave the same. the panner on the stereo channel will not have the same pan law as the original mono channel as set in project settings, resulting in a lower level when panned hard LR on the stereo channel. I use 4.5db pan law generally, and when routing mono audio to a stereo channel in these ways, the pan law on that stereo channel is not 4.5db. the only way for it to be 4.5 again on that channel is to use, for example, boz pan knob set at 4.5db panlaw inbstead of the cubase panner.

frankly this is all pretty weird, and potentially affects no one at all in real world use if you use your ears and start the mix with the routing already set up and the mono tracks already converted to stereo in whichever way you choose. good to know tho. if you convert a mono track to stereo mid mix and its panned at all, it could catch you out.

That is very understandable as there is no panorama on a stereo track. So there is no panorama law. On stereo tracks it is called “balance”. The stereo balancer works in the way that it attenuates the channel opposite of the setting. E.g. if you set the balance all the way to the left, the right channel will be attenuated to -inf.
If balance is set to center the sum of both channels will be 100% of the power of the signal. If it is set full left the sum will only have 50% of the power.

Panorama for mono, on the other hand, regulates how the power of the signal is spread on the stereo spectrum, ie. the sum will always be 100%. If panorama is in the center the left channel gets 50% (that is -6dB) and the right channel likewise. The sum of both channels is 100%. If you set it to full left the left channel has 100% and the right 0% (sum is 100%).
Here is where the Pan Law chirps in. You can use Pan Law settings to NOT have the sum of a mono signal = 100%. It works only for mono channels.

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Of course I meant mid signal… where did I talk about midi?

For some reason I read that as MIDI. Sorry.

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You’re right, lots of the time it doesn’t matter because you’ll just adjust the level until it sounds right. Although different Pan Law settings will impact the gain staging - but everything effects the gain staging, so that always come into play.

However the Pan Law is more important for a signal moving around in the Panorama. Try this- take a mono signal routed to a Stereo Group so you can Pan the signal. Create Automation so the signal Pans back & forth from left to right. Now listen to it with different settings for the Pan Law.

If you’re going for a big Hendrix style guitar solo the Pan Law is going to be more important than when recording a string quartet.

So I still don’t understand. I have a bunch of mono vocal tracks routed to my stereo Vocal group but I can’t pan each individual track left or right.
Is there no easier way than creating a stereo track and copying and pasting each mono track to the stereo track? I would have thought that there would be an easy fix. I"m only using one microphone so of course the track is mono. But I should be able to pan it left or right.

Maybe I’m asking the wrong question.
How do I turn my pan function on?
I’m still using Cubase 12 Pro.

Thanks in advance,

Then you’re doing something wrong. Take some screenshots and share them here so we can see what you’re doing. Intuitively I’d say perhaps you accidentally created a mono group instead of stereo, or have a mono path later in the signal chain.

But what you describe should work.