This will prob make the pros cringe, but... Limiters for Dummies

Sifunkle

Sifunkle

New member
Hi again :)

Please take this thread lightly, because I'm not suggesting this is how I believe it should be done - I'm doing it mostly as an academic exercise, to learn from.

In my understanding, one of the objectives of the mastering stage of music production is raising the volume. I've read that the easiest (/laziest/worst :D) way to raise the volume is to stick a 'brick wall' limiter (one set to -0.01 dBFS or so) on the Master Out and crank the levels as desired.

I thought I'd test this out, partly so I could convince myself it was actually possible for my music to end up loud, and partly to see in what way the result would be worse than the alternative of 'mastering properly'.

So I finished mixing, bounced the track, started a new project in Cubase, imported my final mix, so that all I've got is one channel for the mix track as well as the Stereo Out channel. Using the VSTDynamics plugin that came with Cubase LE, I inserted it onto the Stereo Out channel (last in the chain), and dialled the limiter to -0.1 dB.

Now what I was expecting was to be able to raise the channel with my final mix as high as I wanted without the Stereo Out channel clipping. However it still comes up as clipping, and I'm wondering why.

My current hypotheses:

1. I've stuffed something up, perhaps where I should have inserted the limiter (or maybe the limiter's Release affects it in some way?).
2. My understanding of Limiters is based on theory, and they do not function perfectly in practice, so I was expecting too much.
3. The particular plugin I used is not particularly good.
4. There are different types of limiters, and not all of them can function as 'brick wall' limiters... but...

I find 'brick wall' a redundant term anyway... shouldn't every limiter inherently be a 'brick wall', if my idea that they are just compressors with a ratio of infinity:1 is correct? 'Brick wall' meaning 'complete barrier to the sound intensity rising past a set dB level'?

:confused: Yours confusedly,

Si
 
Stock Cubase compressors and limiter leave much to be desired. I never use them. Search around for recommended third party plugs or pay the money for some good ones. The Waves L2 is what I use.
 
You're not really using it properly. When you stick a limiter on your mix to make iit louder, you shouldn't touch the fader on your project. Leave it at at Unity (0bb). You increase the volume by lowering the threshold on the limiter. Some limiters (like the L2 that Jimmy mentioned), have automatic make-up gain, so that the lower you bring down the threshold, the louder the song gets. Others might not have a make-up gain, which means you have to adjust it yourself. But either way, it's not a matter of turning up your project as loud as you want without clipping.
 
Not all limiters are "brick wall" limiters. Often general purpose compressors can't react fast enough to do what you are wanting to do, even at the lowest attack setting. There are "RMS" limiters that act on the average level rather than the peaks. Also, mastering specific limiters often have a single control that increases the gain while limiting the peaks which is much more convenient than the kind with separate threshold and makeup gain.

+1 to RAMI. If you just slap the limiter on the master bus then raise the fader you are putting the two operations in the wrong order. You could push the channel fader instead and get something of the effect you're looking for. Set the ratio to its highest value and the attack and release as fast as they'll go.
 
Thanks for your responses everyone :)

The limiter packaged with Cubase does not have automatic make-up gain, so I would have had to move a fader at some point.

bouldersoundguy said:
You could push the channel fader instead and get something of the effect you're looking for. Set the ratio to its highest value and the attack and release as fast as they'll go.
Click to expand...

This is exactly what I did. I stuck the Limiter as an insert on the Master Bus, and initially I actually tried adjusting the Master Fader, then realised I was adjusting the level after the limiter had already done its thing, so I returned the Master fader to unity, then raised the level on the other channel (which should have been before the action of the limiter).

I think it did work to some extent, although it still clipped. By my reasoning, if I was raising the level in the chain before the limiter, all I'd be doing would be providing it with more 'work to do' (ie levels above its threshold)?

Perhaps this plugin is just not able to react fast enough; I'll find another on KVR and see how it goes (cheapskate/poor student). Still more than happy to hear more corrections and suggestions :D

Thanks again!
 
Sifunkle said:
The limiter packaged with Cubase does not have automatic make-up gain, so I would have had to move a fader at some point.
Click to expand...
The only thing you have to "move" is the "Make-Up Gain" knob on the compressor once, to set it. Once you've found the best setting for it, you don't have to ride it or move it. Moving any of the faders of your mix is not the way to do it, as witnessed by the fact that you still got clipping. All you have to do is lower the threshold on the compressor/limiter and then adjust the make-up gain accordingly. This is a lot simpler than you're making it.
 
And at *least* allow for .3 to .5dB of headroom (if one can actually call that "headroom" by any typical definition).
 
RAMI said:
The only thing you have to "move" is the "Make-Up Gain" knob on the compressor once, to set it. Once you've found the best setting for it, you don't have to ride it or move it. Moving any of the faders of your mix is not the way to do it, as witnessed by the fact that you still got clipping. All you have to do is lower the threshold on the compressor/limiter and then adjust the make-up gain accordingly. This is a lot simpler than you're making it.
Click to expand...

Ok, I think the setup of the plugin confused me considerably, as the Compressor section had Make-Up Gain (with an auto feature), but the Limiter section had nothing, and I was just viewing the plugin as being equivalent to 3 separate plugins (Gate, Compressor, Limiter) as it's laid out that way.

I figured out if I turn the compressor part on and switch it to 0 threshold and ratio of 1.00, I can use the make-up gain control in the compressor section to act on the limiter. But that's even more confusing: as you cannot arrange the plugin to have the Limiter comes before the Compressor, I don't understand how it's doing make-up gain before the limiter actually does anything. Is it just a poor GUI?

Also, I still don't understand why it didn't work to just raise the level on the channel I imported my mix to, before the signal passed on to the Master Out with the limiter...

And at *least* allow for .3 to .5dB of headroom (if one can actually call that "headroom" by any typical definition).
Click to expand...

Shall do on serious attempts, thanks :) I wasn't aiming for good results on this, it was just an attempt to learn something (which is definitely happening, as it didn't do what I originally expected at all!).

Where you compressing anything during your mixing stage Sifunkle?
Click to expand...

Yes, I did use compression on several individual tracks (vocals, various drum tracks), although not on any submixes, or the final mix. Does that matter? I started a whole new project for mastering and imported the bounced mix (wav file), so I wasn't expecting it to...

Once again, thanks for your responses, and sorry if I'm not getting it straight away. I feel bad to make you keep beating me over the head with it! ;)
 
rfahey86 said:
My best advice. Leave mastering to a Mastering Engineer.
Click to expand...

Sound advice.

Let me rephrase that. I will do pseudo mastering myself to see if things are in the right place. Some clients are good enough with this though I will always recommend a pro do the mastering. I would never master my own stuff ever.
 
May I just reiterate that I'm not trying to master stuff myself as much as just learn something about how a limiter works, in the context of mastering?

Also, I doubt anything I ever make will be worth paying someone else to master.
 
Have you tried simply lowering the threshold on the limiter? Many of them have automatic makeup gain, which is irritating on a track but handy for mastering.
 
bouldersoundguy said:
Have you tried simply lowering the threshold on the limiter?
Click to expand...
Exactly. If the Limiter section doesn't have a Make-Up knob, chances are it's because the make-up is automatic. Turn down the threshold as the song is playing. If there is automatic make-up gain on it, you'll hear the song get louder as you lower the threshold.
 
Once again, thanks for your responses, and sorry if I'm not getting it straight away. I feel bad to make you keep beating me over the head with it! ;)
Click to expand...
Come in late here, but hell with that let's work it out. :p
Sifunkle said:
Ok, I think the setup of the plugin confused me considerably, as the Compressor section had Make-Up Gain (with an auto feature), but the Limiter section had nothing, and I was just viewing the plugin as being equivalent to 3 separate plugins (Gate, Compressor, Limiter) as it's laid out that way.

I figured out if I turn the compressor part on and switch it to 0 threshold and ratio of 1.00, I can use the make-up gain control in the compressor section to act on the limiter. But that's even more confusing: as you cannot arrange the plugin to have the Limiter comes before the Compressor, I don't understand how it's doing make-up gain before the limiter actually does anything. Is it just a poor GUI?

Also, I still don't understand why it didn't work to just raise the level on the channel I imported my mix to, before the signal passed on to the Master Out with the limiter...
Click to expand...
It would help to know what plug your looking at, but more important is getting a handle on the plug (and your) signal flow. If you get to where you can visualize these things in their flow path things get way clearer!
On one end of the range of a few examples that come to mind is the Sonitus comp/limit. It has post comp makeup but no threshold for the limiter (kinda wish it did). On one hand if you do want to hit the limiter you have to jack up the makeup gain (or mix level for a bus insert) to cross 'zero. Then there's also no way to dial in a -.5db' final safety margin on the output.
Timeworks' adds limiter threshold You get pre and post gain as well. (Damn near a default go-to here :D ..for clarity on a master bus ..that's work flow/simplicity, I really like just keeping them both zeroed', and let the limiter set the -.5 final.

Then there's BlueCat Dynamics. more control than ought to be legal..
C/o pg 7 and 8 here
http://www.bluecataudio.com//Vault/Products/Product_Dynamics/manual.pdf
Pre gain, post comp make-up and 'auto (turn that shit off), limiter- no threshold, but there's the make-up ahead and a post final gain so your good to go either way there.
 
rfahey86 said:
My best advice. Leave mastering to a Mastering Engineer.
Click to expand...
not useful advice though for a home recordists.

The same essential advice would apply to the whole thing .... leave playing to a pro player and leave the trcking to a pro tracking engineer and leave the songwriting to a pro writer etc.
You have to start somewhere and even the very best of the best mastering engineers started out with zero knowledge at some point.

If you're preparing a CD for commercial release then you'd do best to have a good engineer master it but otherwise part of the whole home recording thing is to learn stuff and how to do it.
 
Thanks once more for persisting with me :)

bouldersoundguy said:
Have you tried simply lowering the threshold on the limiter? Many of them have automatic makeup gain, which is irritating on a track but handy for mastering.
Click to expand...

Exactly. If the Limiter section doesn't have a Make-Up knob, chances are it's because the make-up is automatic. Turn down the threshold as the song is playing. If there is automatic make-up gain on it, you'll hear the song get louder as you lower the threshold.
Click to expand...

bouldersoundguy and RAMI - Yes, that was the first thing I tried. The song just got quiet as I lowered the threshold, which is why I initially concluded that I'd have to move a fader to manually make up the gain. Doesn't seem like the Limiter on it's own has any sort of make-up gain function.

It would help to know what plug your looking at, but more important is getting a handle on the plug (and your) signal flow. If you get to where you can visualize these things in their flow path things get way clearer!
Click to expand...

mixsit - The plugin is just the one that came with Cubase LE, called VSTDynamics. It's got 3 sections: Gate, Compressor and Limiter, as well as a button to change the order of the sections (not to any combination I want though, just a few presets).

I've set the project up simply so all I've got is the channel with my mix on it ('Mix channel') going into the 'Stereo Out' master channel that Cubase projects always have. I've got the plugin inserted on the Stereo Out channel.

From my perspective, the important parts of the signal flow, in order, were a) the level of the Mic channel, b) the Limiter, and c) the level of the Stereo Out. I anticipated that raising the level on the Mix channel (going into the limiter) would be one way of selecting the limiter's 'activity level', analogous to lowering the limiter's threshold. Seems like the same idea as what you've described for the Sonitus :)

I do realise that the plugin packaged with Cubase LE is probably not going to be the best out there though, so I will check out the ones you posted about :)

not useful advice though for a home recordist
Click to expand...

Thanks for pointing that out Lt. Bob. I think if I'd have said it everyone would have stopped bothering with the arrogant newb :(

I did appreciate the tip that a mastering engineer would get way better results, but I'm not really aiming for perfection. I just want to make demos that my friends won't skip over because they're too quiet. To do that, I think I need some very basic know-how in mastering, which is what I'm trying to acquire by learning how to use a limiter.
 
The manual says...
"Limiter is designed to ensure that the output level never
exceeds a certain set output level, to avoid clipping in following
devices."

"Parameter OUTPUT: This setting determines the maximum output level. Signal
levels above the set threshold are affected, but signal levels
below are left unaffected."

Got'a love it. IDK, to me this is some vague shit. 'certain set output level? OK.
There's no threshold for the limiter. Should we presume this set threshold is 'zero?

Sifunkle seems to me you're doing it fine. Raising the track (by what ever means) into a limiter on the master bus, the 'output set to -.X, that's what it should do. It states it's job is to 'never exceed the set out put'.
Unless we're missing something, like another gain stage or a level in the master path not zeroed... Looks like your job is to push this thing, adjust and poke at it untill you can determin where the heck it does control.
:rolleyes::D
 
Thanks for your support mixsit :)

Despite considerable time and revision, I just couldn't make sense of the limiter on that VSTDynamics plugin, so I eventually gave it up as a bad job. I think it did work to some extent, but just didn't trigger on anywhere near quickly enough. It was certainly no use to attempting to raise the perceived volume.

But I downloaded a free one called LoudMax and it has so far (touch wood) worked exactly how I've expected, and I'm happy with it.

Sorry for the lateness in replying, semester just returned so I have somewhat less time for music now :( My life is planned out so that I can do a half-arsed job of two different things :rolleyes:
 
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