Pan Law: Pan levels in PT? (link)

[Noiz2]

Originally posted by Henchman:
I've never "posed" as a user, but I am a "Past" user.

<font size="2" face="Verdana, Arial">Your posts on this thread, till it was pointed out you wer'nt a user, were all writen to imply you were a user, you explained how this "problem" was costing you $ because your mixes would be rejected. It was all BS.

Damn I got cought again.

[Philthy]

Way to ruin a thread.

[Rail Jon Rogut]

Henchman

So how are they creating the mono mixes at the post house?

Let's go through this..

You're saying okay.. you put in a 1k tone to a track at 0dB and pan it hard left.

You do this in either Pro Tools or Fairlight.. so you have a output of the left channel sending 0dB.

If you're now having this made mono at your video house - unless the post house is using Pro Tools to make them mono.. how can Pro Tools' panner have any effect on the mix? The Pro Tools BTD does indeed drop the center 3 dB if you select "mono summed" as the output format.

The only way the panning in Pro Tools, as George mentioned, could effect your mixes is if you're dynamically panning using the pan "pot" during a mix. If you have balanced your mix and you're happy with it and your pan "pots" are static during the mix, and send it out to be monoed or use PT's BTD mono summing, then your mono mixes are correct under all circumstances.

I'm not saying that technically you're wrong.. it's correct to use a sine-cosine panning with 3dB down at center.. however, as I mentioned in the other forum.. SSL have used 5dB down at center on their analog consoles for years.... and unless you were doing an Eddie Kramer type mix move.. it's all moot.

Rail

[PeeTee]

There is no reason for Henchman's incessant ranting. The "pan law" thread is just another excuse for him to bash Digidesign and Pro Tools...nothing more...nothing less.

Q: Does he use Pro Tools?
A: NO.

Q: Why should he care?
A: It's inconsequential. It's more ammo for him to bash Digidesign and Pro Tools.

[thomoose]

Just be glad youre not using Logic on a native system which has no panning law! yes 0db down for centre pan!!!!

oh the joy that causes!

'best
Tom

(please dont just say 'oh thats native systems for you' theres times when TDM isnt an option.)

[Philthy]

When there's no standard, it's asking for trouble.

In this case, the sad thing is that -3 obviously should be the standard and there's no reason for it not to be implemented.

[Russ M.]

.5 dB is not the end of the world.. But it got me thinking. Now I'm gonna go measure my API pan pots in my analog board. I know they have fixed trim resistors on the to tweek them since the 2 back to back log and reverse log tapers alone most likely would not be 3 db down in the center. By the way 2 years ago I brought up the point that nothing in ProTools seems to follow a log (audio taper) scale.. Not the faders or the EQ curve displays.. Drives me nuts but I've learned to live with it.. No one replied to that then.. Maybe writing code to follow an audio taper is a bit of a problem...
The probable reason for the pans not being smooth from one side to the other is the taper (no log taper) and not the .5 DB down in center.
Correct me if i'm wrong Digi...

[Kev]

There is another consideration.

We have all been thinking about mixing but there is the time when a PAN pot is used to select between 1 or 2 in the subgroups and that might feed the multi-track. What if 1 and 2 went to one track. With all faders at 0dB what would you want to see on the multi-track.

It could be cool for the software mixers and digital hardware mixes to give the user the choice as to which Pan Law they want to use. It can't be that hard. For PrTools you might have a different Mixer to slot into the DAE,
like the DAG, Dithered and now a 2.5pan, 3pan or even 6pan.

[Noiz2]

Not trying to start another fight but this just came up in the CAS board and I do think this is a valid issue, if not quite as big as some do. Any way the following is quoted from there.

"The figure of -4.5dB was established empirically by the BBC Research Dept
and it is a requirement of all consoles sold to them. They are more
particular about that than the fader laws.

While -6dB is easy to achieve electronically it feels wrong. -3dB also
feels wrong and when summed to mono (eg AM radio) could produce +3dB
signals. (Could somebody please explain this to Digidesign so they could
make ProTools conform to professional standards?)

-4.5dB is a compromise, but that is not the end of the story. What is also
important is the way the two channels are balanced against each other to
get a smooth spread across the stereo image. If you look at the law of one
side of a panpot it slopes gently from 0dB to -4.5dB over the first 50% of
rotation, then steeper down to about -23dB at 90% and finally very steeply
down to -90dB. The other side is doing the complimemtary thing and the
stereo image position is the combination of the two. (This is an audio
illusion, the brain usually derives poitional information of sound sources
from delay not level.) It should be obvious that a small error of 1dB can
cause major image position shifts and this is a common problem with cheapo
mixers - they rush past the centre leaving a hole in the middle or the same
knob position on different channels produces different image positions. It
is also hard to achieve a law that sounds right on both monitors and
headphones.

Film LCR pan law is the same as stereo, but between 3 channels in half the
movement i.e. there are -4.5dB points between L & C and C & R at 25% and
75%."