PT Summing Stereo Tracks to Mono - differences between PT10 and PT12

[buyonnet]

Hi,

I have a really bothering issue regarding compatibility with PT10 sessions opened in PT12. I don't know if any of you have encountered the same problem. Here is was I finally wrote to Avid support after running a lot of tests:

I have issues with PT10 sessions opened in PT12 when there is stereo tracks that are either:
- sent to a mono output
- sent to a mono send

Let's say I have a stereo track with a tone generator that gives a constant -18 dBFS level (so, the PT stereo VU for this track shows -18 dBFS on the left channel, as well as on the right one, as intended).

Then, this stereo track is sent to a mono aux (or output, works the same). I use it for example to make the track mono, or to create the Mid part of a MS encoding routing, etc.

In PT 10, the level in the Aux track is -12 dBFS. That's what I worked with forever, and that makes perfect electrical sense, as the same signals L & R from the stereo track are summed. Hence the 6 dB bump.

In PT 12, the level in the Aux track is -15 dBFS. That's not what I expect while summing and it throws off all my PT10 session where there are MS routing.

Furthermore, this causes another problem with the addition of the Pan Law setting. In the example above, the actual level at the output of the Aux Track is affected by the Pan law setting, which is expected. So, with a Pan law of -6 dB, the output level for the routing above is:
- PT10 : -18 dBFS which correlates to the level of the initial stereo track (and is the purpose of the -6 dB reduction from the Pan law)
- PT12 : -21 dBFS which correlates to equal power maybe but if there are more routing after that Aux output, it is a mess

I tried my sessions on PT10 HD and the summing is right, like the summing on PT10 non-HD, meaning +6 dB in the mono Aux.

Could you please help me solve this issue? Is this a bug in PT12? Is this the new way PT sums Stereo track in a Mono send or output? Will I have to change all the fader compensations of -6 dB in my PT10 sessions where I encode and decode MS to -3 dB in PT12 in order to have the same result? (indeed, it does solve the issue but I don't understand why PT12 is not summing anymore the same as PT10 and many other DAW or real equipment, meaning a +6 dB bump)

I have screenshots of the different routings if you like to see them.

Best regards,
JP.

I've attached the screenshots to this post. I'd really like to have any input on this one!

Thanks,
JP.

[Carl Kolchak]

Go to prefs set-up : it looks like you have a different meter type in PT12, so change it to Pro Tools Classic metering, and see if that changes your results.


Sent from my iPhone using Tapatalk

[buyonnet]

I have the same results with other dBFS scale metering in Pro Tools as well as in metering plugins. I put the linear ones in PT12 so that everybody could read the numbers better than with the classic PT meters on the screenshots.

Anyway, the problem is just audible as it wrecks PT10 sessions that use this kind of summing when they are opened in PT12 (MS encode/decode routing especially).

I have one friend who just tried this in his PT12-HD, same issue, no clue neither.

[buyonnet]

Ok, it's a PT12 bug that was at least reported to Avid in November 2015. It's crazy that they let a bug that affects the audio routing (just that...) for so long. What's wrong with Avid?

Read the last post:
http://duc.avid.com/showthread.php?t=372073

[buyonnet]

I have news from AVID about the summing bug in PT12. It seems that a simple text file placed at the root folder can change the summing of PT12 and that would be the patch! Interesting. Furthermore, they ask me to send a non disclosure contract that is pretty heavy to get that patch. I really don't like how AVID manages its customers. Damn, it's a bug that was very difficult to solve in the first messages, now it's a simple txt patch but I'm allowed to have it if I sign a form that last 3 years on several points that prevent me to investigate why their software (which I pay hard money for) is buggy. Crazy...

What do you think about it? Have any of you signed a non disclosure contract in order to have a PT that works?

---
> Entered on: 4/12/2017 5:22 PM Entered by: Rajiv Arora

Hi JP,

A fix has been developed and is waiting to be implemented in the next days, please send me a signed copy of the attached Non Disclosure Agreement in order to provide you with the solution (including a beta build of Pro Tools 12.8) once it becomes available.

Kind regards,
Rajiv

> Entered on: 4/17/2017 8:31 PM Entered by: Customer ( Integration)

Hi,

thanks for the information! Can I wait until it is part of the next
official release (and what is its due date)? I don't especially want to
have to install a PT beta version and work with it... Let me know.

Best regards,
JP.

> Entered on: 4/18/2017 9:19 AM Entered by: Rajiv Arora

Hi JP,

Yes, if you prefer you can wait until 12.8 is available, however I can't provide a specific release date.

The solution that has been developed is not built-in in Pro Tools yet, but comes in the form of a "DigiOption" file, which is a .txt file that you must put in the same folder containing Pro Tools (usually the Applications folder).

In order to provide you with the DigiOption file that will automatically change the summing coefficients in Pro Tools I will still need a signed copy of the NDA, which I am attaching to this mail.

Kind regards,
Rajiv

> Entered on: 5/2/2017 4:19 PM Entered by: Rajiv Arora

Hi JP,

I have still not received a signed copy of the NDA document, please send it to me at your earliest convenience in order to be able to provide you with the file that will adjust the summing coefficients in Pro Tools 12.8.

Kind regards,
Rajiv

---

That looks like they are giving you access to the Beta Version. An NDA is standard procedure so you don't go leaking any new features to the world before they want them known.

[climber]

Originally Posted by otnooishphoo

That looks like they are giving you access to the Beta Version. An NDA is standard procedure so you don't go leaking any new features to the world before they want them known.

^^ what he said... either sign & get, or don't and wait. this is the way software development works.

[deanrichard]

Unless the text file can only be used with PT 12.8 there is no reason for him to want a beta version of the software. It's a simple change to a config file. There seems to be a communication issue here.

Also, IMO the new configuration should be the default and should be part of the PT 12.8 release, or at the very least be well documented so people can make the change themselves. Breaking old projects is not desirable.

Originally Posted by otnooishphoo

That looks like they are giving you access to the Beta Version. An NDA is standard procedure so you don't go leaking any new features to the world before they want them known.

[buyonnet]

Originally Posted by deanrichard

Unless the text file can only be used with PT 12.8 there is no reason for him to want a beta version of the software. It's a simple change to a config file. There seems to be a communication issue here.

Also, IMO the new configuration should be the default and should be part of the PT 12.8 release, or at the very least be well documented so people can make the change themselves. Breaking old projects is not desirable.

That's what I think too! When I first contacted Avid about the bug, I was told it was not critical enough and that was why it was still there (another user raised the issue in November 2015...). Then, it was a complicated bug to solve and I was told not to expect a fix any soon. Then, the bug can be solved by a txt config file to place at the root folder of the app!

But... I can have the text file if I sign a NDA stating among other things that I can't speak about a lot of things about PT for 3 years. It's very disturbing. I worked 10 years in databases management system development in the 90s and no, it's not the way software development works. When a bug is reported and it's impacting a core feature, you issue a patch for all users.

They have a buggy audio core, they have eventually found the time to solve it by placing a txt configuration file in the app folder and they don't release it to all PT users??? Why? Their audio engine doesn't make a voltage addition properly, it seems not to bother them since 1,5 year, they finally have a patch that seems simple to deploy but no, they will give it only to me and if I sign a NDA that would btw forbid me to explain the solution to anyone concerned by this bug. It's crazy.

Not so crazy if they are not sure about the effect of this simple fix on the other PT functionalities. But what don't they get when I tell them that I actually work with PT? I can't afford to run a buggy PT daily, I have sufficient thing to do other than reporting any other bugs the patch would create. Or do they search people to beta test PT12.8? Then, I'll be fine with the NDA but they are nor clear and I don't want to debug their next version just for fun on my work time. I mean, it's not like we pay $300 per year to have a software that just... works.

[biasrocks]

Perhaps the fix is incorporated into 12.8 and not earlier versions.

So even if you have access to the .txt file it won't do anything in earlier versions.

I suspect they want you to test the fix hence the beta version.

Sign the NDA, have direct input into the development of the product and be happy.

Mark