Is it possible for a mono signal to remain mono when exported and at the same level?

[Guy Burns]

I have a mono recording that I am experimenting with inside Premiere to see if I can get an exact replica when I export. I put the recording into a mono audio track, I export as mono, then I open both files in Audition. The level of the exported file drops by 3dB.

Is it possible for a mono recording in Premiere to retain its level? I'm running CS6.

[Richard M Knight]

Do you have a mono or stereo sequence?

[Guy Burns]

Looks like I've got a stereo sequence – must be the default when I set up a new AVCHD 1080p24 sequence. I couldn't find any setting to set up a mono sequence, but I don't want that anyway.

I'm intrigued why the 3dB loss of signal happens. It must be designed that way, but why? Here's what happens:

1. I have a mono signal that just hits 0dB.
2. In Audition, the signal just hits 0dB
3. In Premiere's Source window, the signal just hits 0dB (no numbers are shown, but the signal hits the top)
4. In Premiere's Timeline, the audio graph appears to show the signal just hitting 0dB – but the VU meters on the right show a L-R signal peak at -3dB
5. When I export as mono, and reimport into Premiere, the Source window shows the peak at -3dB
6. When I open that exported mono file in Audition, the peak is at -3dB
7. When I export the original from Premiere as stereo, and reimport into Premiere, the Source window shows the peak at -3dB
8. When I open that exported stereo file in Audition, the peak is at -3dB

There's something here I don't understand. How does Premiere treat mono? Does it think of mono as coming from a SINGLE speaker, so to match the sound level when played in stereo, each speaker should receive only half the signal (-3dB)?

Audition though, seems to treat sound as if it always comes from TWO speakers (let's neglect 5.1). When I use Audition to convert Premiere's stereo export to mono, I end up with the same peak level.

Premiere's mono exports: -3dB

Auditions stereo to mono: same peak level

Help! I don't get it.

[Guy Burns]

Background: Why am I concerned about this mono stuff?

The recordings are from an external microphone when videoing. I am syncing the external sound to the video using Premiere. The recordings are in a wilderness – with very low background noise – but relatively loud talking and footsteps. What I am concerned about is the loss of dynamic range if Premiere is lowering the level by 3dB.

Ques

I have a mono recording which when played in the Source window shows 0dB peak in VU meter (mono) in the Timeline. When I put that recording in the Timeline, the VU meter becomes stereo and shows the level has dropped by 3dB.

No matter how minor, has that level change caused any degradation at the quiet end of the signal level?

[Richard M Knight · Accepted solution]

The problem you are seeing is related to Audio Pan Law, if you do a search in the Audition forum you will find many answers.

Loosing 3db of dynamic range will not be noticeable it will still be greater than any acoustic recording.

If you want to create a mono sequence that might solve your issues use these settings:

[excited_Genie16B8]

FAQ: -3 dB attenuation of Audio in Premiere Pro

[Guy Burns]

Thanks for the comments and suggestions. I posted in the Audition forum as well, and my summation there seems to cover the matter fairly well:

I've never used Convert Sample Type before. Eventually found it under Edit. The defaults are:

Mono to Stereo: Left Mix and Right Mix are set at 100%

Stereo to Mono:  Left Mix and Right Mix are set at 50%

In both cases, all conversions result in the same level. You can do it in a never-ending loop and not lose level. Yet the Favorites that come with the software are set up differently. That's one confusing part. The second confusing part is that when you drag the mono signal into a Multitrack session, the level drops to 71%.

It gets even more confusing: Premiere does it differently: a mono signal when dragged to the Timeline is set to 71% for the L/R channel.

100%? 71%? 50%?

There may be some justification for the various settings based on what used to happen in the analogue world mixers – incoming signal is sent to the wiper of the pan pots, the two ends of the posts being the L/R outputs – but that justification certainly hasn't been applied consistently by Adobe.