Master Fader and First Plugin Question...

[M2E]

I'm just now revisiting this and wanted to know the answer as it's puzzling me. I'm in a conversation with Steven Slate on this at Gearslutz now and wanted to know how Pro Tools handles this first,

If I'm mixing a song, and I'm hitting red on the Master Fader inside Pro Tools software, at this point I'm distorting the signal - right?

So if I decided to put a plugin on that Master Fader anyway (say a Slate Mix Buss or Waves SSL Compressor plugin),
does that plugin now take ownership of the input on the Master Fader?

Am I distorting that plugin before it really does anything or it depends on what the plugin does internally?

When mixing on Pro Tools HD and you use an RTAS 3rd party plugin, you don't get the over light like TDM plugins so, you don't know if ur distorting that plugin before it shows red from the plugins output.

Or, say for instance, you put a compressor plugin after that first plugin, and it never shows that your distorting the first plugin or that compressor. And for some reason, you don't hear that distortion.

What do you guys know on how Pro Tools handles this and if this is ok now in Pro Tools?

Thanx,

Marc

[N8ty]

Plugins on the master fader are post fader

[Top Jimmy]

Originally Posted by M2E

If I'm mixing a song, and I'm hitting red on the Master Fader inside Pro Tools software, at this point I'm distorting the signal - right?

Not if you don't hear it. A few red lights don't mean squat if you don't hear anything happening. In Pro Tools, all they indicate is reaching digital zero.

Now if you hear distortion, that's another story. But technically, whether in HD or LE, the damage does not actually occur until either printing that to file or outputting to converter. Master Faders are specifically designed to pull the signal out of clipping. That is why Master faders have post fader inserts.

So if I decided to put a plugin on that Master Fader anyway (say a Slate Mix Buss or Waves SSL Compressor plugin), does that plugin now take ownership of the input on the Master Fader?

No. Again, inserts on Master Faders are post fader.

Am I distorting that plugin before it really does anything or it depends on what the plugin does internally?

It all depends on whether you're on LE or HD, and it only indirectly has anything to do with floating-point and fixed-point notation. In LE, you can turn down the last plugin in the chain and bring it out of distortion regardless of where the over occurs. Why? Because 32-bit floating-point is passed all the way through everything. (Unless, of course, you're using hardware inserts.)

In HD, the limiting factor is that the interface between the TDM bus and the TDM plugin is limited to 24-bit fixed point even though the mixer runs at 48-bit fixed. Anything above the ceiling is permanently clipped when transfered in and out of plugins. When you see a clip light on a TDM plugin, you're not clipping the plugin, you're clipping the interface between the plugin and the TDM mix bus. Turn the output of the plugin down and there's no more problem.

When mixing on Pro Tools HD and you use an RTAS 3rd party plugin, you don't get the over light like TDM plugins so, you don't know if ur distorting that plugin before it shows red from the plugins output.

Or, say for instance, you put a compressor plugin after that first plugin, and it never shows that your distorting the first plugin or that compressor. And for some reason, you don't hear that distortion.

Again, you're not distorting the plugin itself. It's the interface between plugin and mix bus that's distorting. Every plugin has greater internal headroom than is available to pass along to the mix bus. If RTAS plugins never show clipping on HD, that probably indicates that they are able to pass more than 24-bits to and from Pro Tools.

[jeremyroberts]

Originally Posted by M2E

I'm just now revisiting this and wanted to know the answer as it's puzzling me. I'm in a conversation with Steven Slate on this at Gearslutz now and wanted to know how Pro Tools handles this first,

If I'm mixing a song, and I'm hitting red on the Master Fader inside Pro Tools software, at this point I'm distorting the signal - right?

So if I decided to put a plugin on that Master Fader anyway (say a Slate Mix Buss or Waves SSL Compressor plugin),
does that plugin now take ownership of the input on the Master Fader?

Am I distorting that plugin before it really does anything or it depends on what the plugin does internally?

When mixing on Pro Tools HD and you use an RTAS 3rd party plugin, you don't get the over light like TDM plugins so, you don't know if ur distorting that plugin before it shows red from the plugins output.

Or, say for instance, you put a compressor plugin after that first plugin, and it never shows that your distorting the first plugin or that compressor. And for some reason, you don't hear that distortion.

What do you guys know on how Pro Tools handles this and if this is ok now in Pro Tools?

Thanx,

Marc

Marc,

Let's talk about master faders.

You say you are using a master fader, but what is the master fader controlling?

your mix bus?
your hardware outputs?

think of a master fader as a VIRTUAL FADER for the audio path, and not the actual path of the audio.... this is a big concept. Let's go there again:

A master fader is present on every bus and output in protools, by default at unity (-0dbFS) and simply hidden. Yes -- for every bus, every output, there is a master fader already built into the mixer. Therefore, if you "create" a master fader, you are not doing anything more than making the master fader VISIBLE to the session (and you can then do stuff with it).

The audio path has not changed.

So -- getting back to your audio path -- WHERE is the audio going that you made a master fader visible?

WHY did you choose to use a MF?
What is purpose of making the MF visible?

Many people use a MF where they should be using an AUX

What is your 2mix bussing architecture? That is, how are you getting your 2mix from the mixer to monitor and to print a mix? This sounds very basic -- but it is THE fundamental error that many make when using PT.

So step back and look at your routing. If your 2mix bus is hot, you would use a MF to pull it back. You would make visible a MF for the 2mix BUS.

Why are you putting a plug on the 2mix MF? Do you want a post-fader insert on the 2mix? Or do you want a PRE fader insert on the print bus? it can be one and the same... but you have to know why you are choosing the routing. I sometimes use both -- for example, if a song has a fade, and I want some bus compression before the fade, I will insert on the print AUX, not the 2mix MF. There are creative reasons to go one way vs. the other.

BUT THE FIRST THING YOU MUST DO is be very clear about how and why you use master faders. A good habit to get into is to SAY -- "I need to make the master fader visible because...." There are only 2 reasons in my book:

1. need to pull down (or in some cases, boost) a bus level.
2. need an insert on the bus POST FADER -- that is, before the audio goes to its next place in the mixer - and is better served by inserting the MF vs. the first insert at the destination.

Just know your audio paths and why you are sending things from here to there. I think every protools mixer should spend a decade working on analog desks before they turn on PT -- and watch how quickly protools routing becomes the most basic and obvious way to work.

So the short answer to your original question: if you are inserting a compressor on the 1st insert of MF and the bus is clipping, you are gonna clip the input of the plug. BUT -- since MF plugs are post-fader, it's as simple as pulling the MF down to achieve the desired bus level for input to the plug.

BUT -- remember there is an ideal bus level you should be working at -- and that is generally 0vu = +4dBu = 1.228v = -18dBFS (and now the proverbial can of worms has come to the the surface) -- so if your bus is clipping -- by all means pull it back before you send it somewhere else!

I hope this helps.

J

[M2E]

Thanx to all that are getting me past a very weird mental block in my head.

To N8ty - Yep, I knew that but, thanx for letting me know again. It's weird to me that I can't get this in my thick skull.

To Top Jimmy - I think what confuses me is the plugin part. They are soooo different in headroom regardless of RTAS/TDM.
When I use the Waves SSL, I can push that thing about 6 to 7 db over -0db before hearing distortion at all. Then I go to a plugin like Analog Channel or the like, and can't go over 0db before hearing distortion right off.
I guess I need to take a day like today, and just get this in my head for good.

To jeremyroberts - WOW, great breakdown. You and Jimmy did explain that well.
I kind of agree with you about people learning about analog desk's as it may help somewhat no-a-days.
I came up doing this (writing/producing/mixing) in the early 90's and came up on Neotek (Close friend's home studio), SSL (Battery Studios in Chi-Town, Thanx to Stev-o, & Music Grinder and many more studios), Neve (Music Grinder Studio's in LA and other studio's in London), and Mackie (Owned for many years with Alesis Adat's and then Pro Tools Mix +), so I know about TT patchbay's and routing them pretty well. Just for some odd reason, I keep forgetting this and I really do think I have some type of PT's mental block about this.

Anyway, thanx guys for taking the time to explain this to little old me. Sorry for the mental block. I'm going to fix this today for good.

Marc

[crizdee]

Originally Posted by M2E

When I use the Waves SSL, I can push that thing about 6 to 7 db over -0db before hearing distortion at all. Then I go to a plugin like Analog Channel or the like, and can't go over 0db before hearing distortion right off.

Hi,

The Waves SSL have been modelled to be that way! you can push then into the red like the analogue hardware!

Master fader = Metering plugins only
Mixing -18 RMS -6 peak is where to aim for.

Old habits die hard and i get sent many sessions that are clipping the master fader.

Try placing the trim plugin on the master fader set to +6 db you'll feel more at home


Chris