Mono channel/ Mains db

[CoolName]

Hi. I have a mono bass channel that goes direct to the Main output stereo channel/ Master. I put a level meter inserted on the bass channel and the peak is -12. On the Mains I put a level meter and the peak is -15. Why is it 3db lower? Is that something to do with pan laws?

Thanks

 

[Wolfger]

Hi. I have a mono bass channel that goes direct to the Main output stereo channel/ Master. I put a level meter inserted on the bass channel and the peak is -12. On the Mains I put a level meter and the peak is -15. Why is it 3db lower? Is that something to do with pan laws?

Thanks

Yes it´s Pan Law! From an Sound On Sound Article:"...If you want the panned sound to be perceived, acoustically, as remaining at a constant volume regardless of the pan position, then the centre attenuation needs to be 3dB. This is because the acoustic summation of two identical signals increases the perceived volume by 3dB."
Studio One has a fixed Pan Law of -3.
in Stereo Channels you can use the Dual Pan Plugin to use a different Pan Law though.

 

[CoolName]

Ok thanks. I thought because the bass guitar was simply in mono that no pan law applied. It is right down the middle, not panned and registers 3db louder on its channel meter than on the Mains.

 

[Wolfger]

Yes, that´s how pan law works. A mono sound played through the mainout would play equally on the left and right speaker. A mono sound panned hard left to the left speaker only would therefore sound lower in volume. to compensate for that loss in volume you could either turn up the sound when its panned hard left, or turn it down when it´s in the middle. Studio One´s -3 Pan law turns down the sound -3db when it´s in the middle.

 

[Wolfger]

Logic Pro offers different Pan Laws:
Pan Law -3 mid

Pan Law-3 L

For example -3 Compensated mid:

-3 Compensated L:

 

[CoolName]

So I suppose the reason for doing that is because if you sent a mono channel to the stereo Mains then basically you're sending 2 copies...a left and a right...and without a pan law the signal would present as louder in the Mains than on the channel?

 

[Wolfger]

So I suppose the reason for doing that is because if you sent a mono channel to the stereo Mains then basically you're sending 2 copies...a left and a right...and without a pan law the signal would present as louder in the Mains than on the channel?

Exactly

 

[SwitchBack]

Sort of. The historic reason is gain structure: Full left or full right must not be a higher output level than the mono signal going into panning, so coming from center you need some gain in hand. 3dB is the most common choice, allowing the side you pan to to get a bit louder whilst the other side turns down, keeping the overall perceived level more or less the same when panning. But keeping that perceived level the same also depends on the content of the audio so there are several pan laws to choose from.

 

[Wolfger]

........... so there are several pan laws to choose from.

Unfortunatly not in Studio One (except in the Dual Pan Plugin)

 

[SwitchBack]

Well, the default pan law does the trick 90% of the time, and for static settings it's a bit academic anyway. The Dual Pan plugin is available for dynamic panning on channels with 'non-standard' content. But having options is always nice, so who knows...