Proper Gain Structure & dbfs?

[MyKill]

Great posts, Compyfox. You have a patience of a teacher.

One tip about Satson CM: when you boost the gain on it, it adds a bit of bass at 40Hz, and of course more saturation at 2nd and especially 3rd harmonic that becomes stronger with higher gain and overtakes the 2nd harmoonic. The more gain, the more bass boost and saturation. When you lower the gain the frequency response stays rather linear and there's less saturation.

Again, just for clarification, you mean it adds more to the 2nd and 3rd harmonic of the source signal independently, or it adds overall boost to the 2nd & 3rd octave (40-160 Hz)

And, yes, all you guys have been extremely patient and forthcoming with your knowledge, and I thank all of you for it

[Compyfox]

Again, just for clarification, you mean it adds more to the 2nd and 3rd harmonic of the source signal independently, or it adds overall boost to the 2nd & 3rd octave (40-160 Hz)

To my understanding of Satson, if you use it as DUX described, it adds an overall boost to the bass and the 2nd & 3rd harmonic. Which is only logical.

Stronger input gain, a saturation effect going on.

If you were to put the plugin on a buss, or post-fader, then gain staging wouldn't matter. In practical use however, it's important due to the plugins we might use on a track.

It matters either way as you route signals both in series and in parallel.

Example: channel -> group

Don't get the gain staging right, and you add up your signal strength over and over. The endresult is a way too low fader resolution (which you simply don't need!).

Also, you constantly overdrive your plugins. And especially old plugins (that might be still on 24bit processing in a 32bit float environment - looking at you Waves and UAD/Powercore!), or emulations with a reference level, will clearly punish you with unnecessary distorted sound or pumping effects.

Great posts, Compyfox. You have a patience of a teacher.

Thanks. Though I definitely don't feel like being a teacher.

But it's not surprising that I was ask/recommended to go into consulting several times by now.

[MyKill]

Tank you all again for all the helpful insight. One final (don't hold me to that) question. With all this talk of digital meters (dbfs) and VU meters (average RMS), where does a PPM meter come into play in this scenario... or does it at all?

[Compyfox]

A digital meter is sample accurate.
A PPM is a "Peak Programme Meter" and uses a 5-15ms for peak measurement.
A VU or RMS meter uses 300ms for measurement and is for average levels.


PPMs are still used in outboard consoles (especially budget ones) unless explicitly written that it's a digital meter. Within hosts, you mostly only have a digital meter, and sometimes an RMS meter / VU as bonus measurement tool.

[MyKill]

All right fellas, one last question (seriously this time) and we will put this thread out to pasture. And it's not a theory question, its a mechanics of Cubase question.

...keep the volume of all the tracks in the mix around, but not beyond, -18dB average RMS, and use the VU meter for that... Also, keep the same volume between the plugins... I use Satson CM for that.

...I'll just chime in with how I do that in practice.
I use VUMT set to -18db in all channel to set up the gain according to the rules described by Compyfox, with the Cubase channel faders set to default.

I actually do that with Slate VCC (bus plugin), if I want to overdrive the bus on purpose. So the chain would be:

Gain (boost) -> Console plugin -> Gain (attenuate the same ammount as with boost)

I got a more saturated signal, but I'm still at a suitable worklevel.

I also compensate the ouput of compressors and to a certain excend even EQ's. So if I hit "global bypass" for a channel, I can easily hear what's going on and whether or not it's doing the signal any good without having any huge volume/loudness bumps.

I understand you are viewing the VU inserted on the Stereo/Master Bus and that is where you judge if the signal is at 0VU, using the Satson (or whatever)on the individual channels as simply a gain stage. My confusion comes with the lack of a Cubase Gain plug in and the "Global bypass = no major volume drop" thing.

If my recorded bass track, untouched by processing and channel fader at unity, is displaying a VU of +3 (on the Stereo Master buss VU), obviously I need to adjust the pre-fader Gain knob at the top of Cubase's channel strip to get it near 0VU. Easy Enough.

Now let's say I like the the Gain/saturation stage of the Satson better than that of Cubase and I want to use that to get the signal to 0VU. I believe I would simply turn down Cubase's own Gain knob to get the signal under that reading, then insert satson on insert 1 and turn its Gain knob till I was hitting 0VU. If my assumption is correct, that's Easy Enough as well.

But..... then if i were to hit the insert "global bypass" for the channel with the goal of no volume difference, that would not work as I'm using insert 1 as the main gain control, and it would be a big drop in volume if bypassed. The only way I see to accomplish this in Cubase would be to drop the Cubase gain knob, put a Satson in insert 1 and adjust it's gain knob till you get 0VU in the Master Buss with all faders at unity, save that setting as as a preset and run it as an offline process on the audio file. THEN you could have the proper starting level and apply any plugins you like, and as long as you are compensating the output levels of them, you could do a global insert bypass for the channel and have no significant volume difference. I'm not that lazy and am willing to do that if that's what it takes, but is there a more streamlined method?


Seeing that you also stated you use the chain
"Gain (boost) -> Console plugin -> Gain" and Cubase has no actual plug in for Gain(only an offline process), I'm wondering how you accomplish that. I suppose you could insert the Satson after the console plug in, turn off it's saturation mode, and only use its Gain knob for actual gain changes. That would also accomplish the "global channel insert bypass = no significant volume drop" thing.

I'm asking because you guys are giving examples of how you do what you're talking about using the same DAW that I am, so I'm just trying to get how you're physically accomplishing your chain.

Let put this thread to bed!

[Compyfox]

I understand you are viewing the VU inserted on the Stereo/Master Bus and that is where you judge if the signal is at 0VU, using the Satson (or whatever)on the individual channels as simply a gain stage. My confusion comes with the lack of a Cubase Gain plug in and the "Global bypass = no major volume drop" thing.

VU on channel = leveling in
VU on summing bus = mix level

Correct.

I'm not that lazy and am willing to do that if that's what it takes, but is there a more streamlined method?

Yes, there is. As you assumed already. It's a gain plugin.

Seeing that you also stated you use the chain
"Gain (boost) -> Console plugin -> Gain" and Cubase has no actual plug in for Gain(only an offline process), I'm wondering how you accomplish that. I suppose you could insert the Satson after the console plug in, turn off it's saturation mode, and only use its Gain knob for actual gain changes. That would also accomplish the "global channel insert bypass = no significant volume drop" thing.

You could use the Cubase internal "limiter" for that task, but it's a PITA to control. Personally I use MeldaProduction's MUtility for that purpose. Any third party gain plugin would work, or something that the host has built in (Logic for example does have a dedicated gain plugin, since it doesn't have a gain/trim knob per channel, same with Reaper). I just happen to have this plugin set on my HDD. So I'm using it. GVST's Gain plugin might be just as suitable, btw. Whatever you have at hand and feel comfortable with.

The method I described is I want to overdrive a specific module on purpose, but I need to compensate (attenuate) the same amount of dB that I used to boost before I went into the module.

So if I want to intentionally overdrive a device by 3dB, it goes like this:

Gain +3dB -> Module to be overdriven -> Gain -3dB

Of course the VU of the particular module would be off by 3dB. But at the end of the chain, it doesn't matter.

Let put this thread to bed!

I wouldn't do that. Ton of info in here, no?

[MyKill]

I'm not that lazy and am willing to do that if that's what it takes, but is there a more streamlined method?

Yes, there is. As you assumed already. It's a gain plugin.

But that's the heart of the issue. If I use the Satson as a gain plug in as insert 1 and use it to "level" my signal, then apply processing and compensate volume for the rest of the chain, if I were to hit the "insert bypass" for the channel, the volume would drop significantly since insert 1 is adding all the gain. The only way I see to get the signal to a point where bypassing inserts creates no real level drop while using the Satson gain stage as my main gain is to offline process the Satson and then start with an empty insert chain...

[MyKill]

Let put this thread to bed!

I wouldn't do that. Ton of info in here, no?

I didn't mean kill the thread, but i realize that there is a limit to peoples generosity and a point where they don't really feel like explaining anymore. Just trying not to wear out my welcome...

[Compyfox]

You're thinking way too complicated.


Just see the Cubase internal gain knob (per channel) as the knob that initialy sets up the channel gain, which all other plugins adapt to.

Example:
Have a bass. It's currently peaking at -12dB and would go completely into the reds on a VU (if that's setup to -18dB RMS). Now... use the Cubase internal gain boost/trim knob prior to the VU/console plugin/whatever, bring the signal down to -18dB RMS. Done.


To answer your question with the gain drop on global bypass:
After I've setup the signal initially (note that I do not touch the console/VU gain boost/trim knob at all!), I continue working with gates, EQ, compressor and the likes.

I try to match the output of each individual plugin (mostly EQ and compressor, but also guitar amp plugins - whatever comes to mind) so that it has about the same volume as the bypassed signal. And this is all there is to it.


Now... if I'd like to A/B a channel signal, I can easily press the global bypass button and be happy. No sudden jumps. Plain and simple.

Would you be using Logic, Protools or Reaper, it wouldn't be that simple as they don't have channel pre-filters like Cubase does. So globally bypassing a channel's inserts does result in a volume jump. And you can't prevent that. So be happy that you use Cubase, or get used to offline processing. *cough*



Only if I want to INTENTIONALLY overdrive a plugin, I use the "Gain Plugin -> Module to overdrive -> Gain Plugin" combo.


Does this make it a bit more clear now?

[MyKill]

You're thinking way too complicated.


Just see the Cubase internal gain knob (per channel) as the knob that initialy sets up the channel gain, which all other plugins adapt to.

Example:
Have a bass. It's currently peaking at -12dB and would go completely into the reds on a VU (if that's setup to -18dB RMS). Now... use the Cubase internal gain boost/trim knob prior to the VU/console plugin/whatever, bring the signal down to -18dB RMS. Done....
Does this make it a bit more clear now?

yeah, I'm clear on all that now, I guess what I'm asking is a plugin specific question. Example:

Method 1:
Bass track on its own sits at +3. Turn down Cubase pre-fader bass channel gain to get it to 0VU. Cool, done...BUT i like the saturation from the gain of Satson and want to use it. I could, after my signal is leveled by Cubase gain, add the Satson as insert 1, keep the saturation switch on and drive it till it sounds good, then place another Satson (or MUtility, which I have btw and will try it when i get home...I'm on company time right now - bwa hahahahahah!!!), turn off the Saturation switch, adn just use the gain knob to get the signal level back down to its previous pre-Satson state. Good.

Method 2:
I want to use the Satson Gain/saturation as THE MAIN gain source. In this scenerio, I would use Cubase's gain knob to turn the level down even lower, say -3 VU, THEN use the Satson Gain knob with saturation on to get the signal to 0VU. In THIS situation, the insert is the thing actually bring the signal up to nominal level, so if master insert bypass is pressed, the level would drop noticeably. So IF I wanted to use this method, i would have to OLP the Satson, then I would have a signal at nominal level with an empty insert chain and any inserts applied, if volume output compensated correctly, could be master bypassed and have no noticeable level drop.

i guess what I'm asking is, I understand the how and why, but is there any advantage/disadvantage to using one method over another?

[Tricky-Loops]

Example:
Have a bass. It's currently peaking at -12dB and would go completely into the reds on a VU (if that's setup to -18dB RMS). Now... use the Cubase internal gain boost/trim knob prior to the VU/console plugin/whatever, bring the signal down to -18dB RMS. Done.

Why don't you lower the gain of the bass in an audio editor if it's already peaking at -12dB? Wouldn't this be easier?

Would you be using Logic, Protools or Reaper, it wouldn't be that simple...

Why do I need a gain plugin before the FX? Of course, it would be nice to have an "input" control in REAPER but until now I could live without it...

Anyway, there is a "Pre FX" control in REAPER, so wouldn't it be possible to make a send to a track (with a gain plugin as insert) and use this as input gain?

[Compyfox]

i guess what I'm asking is, I understand the how and why, but is there any advantage/disadvantage to using one method over another?

Two things to consider:

a) do you want more distortion/saturation of the signal?
b) in case you can't compensate the signal, can you live with the volume jumps?


If this is apparent to you, nobody is stopping you from using your tools however you feel like. This is just a guideline how to use optimum worklevels. You decide if you want to bend or even break the rules.

Why don't you lower the gain of the bass in an audio editor if it's already peaking at -12dB? Wouldn't this be easier?

I have to admit that I'm oldschool and do not mess in audio editors (destructive editing) but rather go for knobs (non destructive). Though volume changes in an audio editor in Cubase can be handled non-destructive these days, I don't feel comfortable doing so.

Sometimes it also renders it impossible to do automation, fades and the likes. So... I stick to the mixing console.

Why do I need a gain plugin before the FX? Of course, it would be nice to have an "input" control in REAPER but until now I could live without it...

We're talking about a gain plugin pre a console plugin, or a plain VU, while both using a reference level. In this case, you need a gain plugin in front of them. Unless they feature boost/attenuation with +/- 24dB or even 32dB.

The advantage of having a gain module (best if it's integrated in the host) prior to any plugin, is that you can setup your levels first, then forget them. If you globally bypass anything, there are no volume jumps.


The method I'm talking about (gain staging) is a relic from the old days. Though it still makes sense these days and is more important than ever. It's to prevent overdriving of certain plugins (emulations especially), easier integration of hardware, having a better fader resolution, you don't need to touch the master fader and you have plenty of headroom for your ADC/DAC.

Of course you can mix and record at your DAW's limits, but isn't it better to not constantly compensate levels, think about clipping and the likes?

Anyway, there is a "Pre FX" control in REAPER, so wouldn't it be possible to make a send to a track (with a gain plugin as insert) and use this as input gain?

Maybe my brain is blocked at the moment, but wouldn't that be overly complicated?

I'm not that skilled with Reaper (yet), but I do remember a link to a gain plugin is possible (per channel), and that can also be "pre everything" and global bypass can ignore that one. At least to my understanding.



Anyway... do whatever you feel works best for you. I re-adapted gain staging from the old days. And I can work care free.

[Tricky-Loops]

Anyway, there is a "Pre FX" control in REAPER, so wouldn't it be possible to make a send to a track (with a gain plugin as insert) and use this as input gain?

Maybe my brain is blocked at the moment, but wouldn't that be overly complicated?

I'm not that skilled with Reaper (yet), but I do remember a link to a gain plugin is possible (per channel), and that can also be "pre everything" and global bypass can ignore that one. At least to my understanding.

You're right, there's an easier way for an input gain:

http://forums.cockos.com/showpost.php?p ... stcount=14

BTW, is there an easy-to-read tutorial about (old-skool) gain-staging generally? Even for people like me who are new to (gainstaging) school?

[Compyfox]

Just read up on the first posts by me in this thread (also there is a link to a video). Or hit my KVR marks. Maybe find posts on the topic by Kim Lajoie.


I haven't prepared a written tutorial for my tech-blog yet. Too much to do. But I think it's about time to cover that topic.

[MyKill]

... hit my KVR marks.

I have done so and saw you talking about the PSP Meter which i have as well. I've tested your suggestions on my own mix and it seems to be working. But I've run into one issue that I cant figure out, and that is the difference I get on the VU's with Pan Law changes. Now, first, I get pan law and its purpose as I have already had a long post asking for help on that topic. I ran an few tests and am confused by the result. I tried this with a sine wave and a bass track and got the same result.

- Pan law set at -3

- mono channel feeding straight into the Stereo Output bus; insert 1 is the test generator plugin producing a 1kHz sine wave at -18dBFS, panned center

- an instance of Satson (and tried with PSP Vintage meter, same results) on the same channel, POST FADER

- an instance of Satson on the Stereo Bus Insert 1

The readings are:

audio channel dBFS = -20.9
audio channel Satson VU post fader = ~ 0

Stereo Channel dBFS = -20.8
Stereo channel Satson VU = -3

Now at first glance, I see the pan law is dropping my centrally panned channel by ~3 dBFS. Got it.
It gets louder in the Stereo Bus (-20.8 dBFS), I'm assuming due to summing or something else I don't fully grasp. OK.

Now, if my channel is being dropped by ~ 3 DBFS in it's own channel, I get that. But what I don't get is how my Stereo Bus is +0.1 dBFS LOUDER than the channel, yet its VU reading is 3 VU lower

I thought maybe it had to do with my Satson in the Post Fader channel position perhaps not being post-PANNER, but I dont get how something is louder with one tool (dBFS) and quieter with another (VU)

I also tried this with 0 dB Pan law, and the dBFS from channel to Stereo Out raised by +0.2 (summing?), but the VU was the same on the channel and Stereo Out. Also, when panning the sine wave hard L & R with -3 pan law, the dBFS and VU match from channel to stereo out. So how does a Bus being fed a signal have a higher dBFS but a lower VU?