Using limiter as a peak controller

[s-cube]

Hi guys,

I have a simple question, would you guys advise against using a limiter on the master bus just to control peaks?

For example, putting an L2 on the master with the output level set to 0.02 just to avoid any random peaks that might clip the master channel.

I usually try to fix these problems in the mix itself but on some tracks there might be a couple of points where some elements combined clip the master by a db or two. So is it advisable to control these peaks with a limiter? As long as the limiter just control these random peaks it won't change the audio in any other way will it?

[Boomshanka]

If it means you're getting gain reduction on the limiter only very occasionally per song, probably no harm in it mainly if it's reacting only to rare, extremely short transients (HF).
Still, even better to mix in order to peak several dB below full scale. If mixing digitally any peaks that would be overs simply needn't be "random" at all but known.
So yes, in general I'd advise against it.

[philosi]

The Pendulum PL-2 works extremely well.

[s-cube]

Thanks for the replies guys, unfortunately hardware is out of the question.

I can fix it in the mix by lowering all the group channel faders by a db or two until the master stops clipping. However this means that when it comes to mastering i will have to limit the mix by an additional db or two which will possibly hurt the mix more.

So i just wanted to know which option is better, just catching those random peaks as they only occur a few times or lowering all the faders until the master doesn't clip anymore (but then having to work the limiter even harder).

[Jaques Beraques]

I think if there are only a few peaks that peak above 0dB, you should maybe edit them manualy.

[s-cube]

How about if i just open up the mix in soundforge & zoom in on those clips & then lower the volume until it doesn't clip anymore.

[bob katz]

Originally Posted by s-cube

Hi guys,

I have a simple question, would you guys advise against using a limiter on the master bus just to control peaks?

For example, putting an L2 on the master with the output level set to 0.02 just to avoid any random peaks that might clip the master channel.

I usually try to fix these problems in the mix itself but on some tracks there might be a couple of points where some elements combined clip the master by a db or two. So is it advisable to control these peaks with a limiter? As long as the limiter just control these random peaks it won't change the audio in any other way will it?

For fixing "visible" but supposedly inaudible peaks, there is ABSOLUTELY NO GOOD REASON TO USE A LIMITER AND PLENTY OF GOOD REASONS WHY YOU SHOULD NOT.

The fact is that if you are mixing, and you have a meter, then all you have to do is reduce the master fader until it doesn't overload. No reason to use a peak limiter. You could easily be subtly affecting the ultimate impact, clarity and potential of your mix if it is going to be later sent for mastering.

The only time you should consider a peak limiter in mixing is if there is an AUDIBLE peak that annoys you, and even then I suggest you collaborate with a mastering engineer since a good mix should sound dynamic and impacting and that peak would have to be disturbing to the musicality to be considered. Even then, a careful fader move to soften the peak can be less damaging to the impact than using a peak limiter. Or put it on the offending instrument rather than on the bus.

BK

[Ben F]

Originally Posted by s-cube

Thanks for the replies guys, unfortunately hardware is out of the question.

I can fix it in the mix by lowering all the group channel faders by a db or two until the master stops clipping. However this means that when it comes to mastering i will have to limit the mix by an additional db or two which will possibly hurt the mix more.

So i just wanted to know which option is better, just catching those random peaks as they only occur a few times or lowering all the faders until the master doesn't clip anymore (but then having to work the limiter even harder).

Instead of lowering the fader, just a put a limiter on the fader causing the peak.

[MASSIVE Master]

Or just lower the level of the mix.

Geez, is everybody allergic to just a tiny little bit of headroom for some reason?

[bob katz]

[/quote]

I can fix it in the mix by lowering all the group channel faders by a db or two until the master stops clipping. However this means that when it comes to mastering i will have to limit the mix by an additional db or two which will possibly hurt the mix more.

[/quote]

This doesn't make any sense at all... I repeat: If you need to peak limit to obtain a particular sound, then do it, but exercise the cautions expressed elsewhere and in this thread.

Mixing is mixing. Mastering is Mastering. Don't get the two confused.

If you are doing it during the mix, supposedly "for the meters", or to "maximize" your mix levels---FORGET ABOUT IT. It will likely hurt the sound later. Just drop the master fader until there is some air between the peak of the music and full scale on the meter. There is absolutely NO REASON for a mix to hit full scale at ANY time.

You'll get the same sound (probably better) and make it EASIER, not harder, for the mastering engineer to get a good sound and a "loud' record.

BK

[lalalalala]

Originally Posted by s-cube

How about if i just open up the mix in soundforge & zoom in on those clips & then lower the volume until it doesn't clip anymore.

But you're mixing with a DAW, right? All DAW software has the option to normalise audio, and you can apply the volume reduction to selected parts of the audio. That's the first option and best way to reduce a spike in a track, right? Or am I missing something??

[diogo_c]

Originally Posted by MASSIVE Master

Or just lower the level of the mix.

Geez, is everybody allergic to just a tiny little bit of headroom for some reason?

I guess 99% of the MEs are!

I use Roger Nichols Finis on all my songs, but I like to check the whole mix without it and then calibrate the master fader accordingly. So Finis is doing more of a "fail-safe" job for occasional overs than actually compressing the peaks - there's even a preset called "occasional overs" on it for that.

Cheers!

[s-cube]

Thanks for the replies guys.

Originally Posted by Ben F

Instead of lowering the fader, just a put a limiter on the fader causing the peak.

Usually it's the combination of a lot of channels making the master clip so that is not really an option.

------------------------------------------------------------------------------------------------------------------------------------------------
Bob, i understand what you're saying but i think i wasn't clear about what i wrote. I didn't suggest using the limiter to maximize the mix, i'll leave that for the ME. What i meant was that otherwise the mix will be good, all the levels perfect but there will be an occasional instance where lots of elements combined might clip the master by a tiny amount. So the question was whether it was a good idea to catch this transient in the mix by setting the output of a limiter to 0.02, so that it doesn't do any limiting but catches this transient. As this transient is only at one or two places in the track, essentially all the limiter would be doing is reducing these peaks. However now i realize that even if it is only doing that it might still be adding color to the track so it's better to fix the mix by lowering it instead.

Anyway, i usually mix by routing all my channels into groups, so if at any time the mix is too hot i just lower all the group channels instead of having to select all the channels in the mixer & lowering them.

You suggest lowering the master fader in case of any overs. Wouldn't this mean i'm losing some quality? I normally try to leave the master channel at 0db & adjust the channels instead. Sorry for the newbie questions.

[Jaques Beraques]

People are argueing if its O.K to pull down the Master-Fader but i think its no problem. Maybe old DAW's had a problem with this but the modern systems don't have it. It is definetly better than putting a Limiter on the Master.

[ripper]

Originally Posted by diogo_c

I guess 99% of the MEs are!

I use Roger Nichols Finis on all my songs, but I like to check the whole mix without it and then calibrate the master fader accordingly. So Finis is doing more of a "fail-safe" job for occasional overs than actually compressing the peaks - there's even a preset called "occasional overs" on it for that.

Cheers!

OUCH!!!

[dynomike]

Originally Posted by s-cube

You suggest lowering the master fader in case of any overs. Wouldn't this mean i'm losing some quality? I normally try to leave the master channel at 0db & adjust the channels instead. Sorry for the newbie questions.

Two things:

1. Don't use a limiter simply to satisfy your meters. Bring down the fader.
2. Less Level DOES NOT equal Less Quality.

I don't know what software you're using, but I've never heard any problems with lowering the master fader. On the other hand, I have heard lots of problems with overlimiting, or careless digital overs. Your logic that "If I don't deliver a limited mix, they'll have to limit it more in mastering and it will sound worse" is very much flawed. Bring down the master fader if all you want is for it not to clip. I know its scary, but trust me... ;)

[smoke]

Hi Guys. Similar boat here.

Consider that the music is a very dynamic classical piece. There are sections that are low in level, and there are sections that are loud for impact and contrast.

In my case, the mix is not clipping. It's after I bounce into a 'master' session, after a chain of parallel compression/gain staging when I get 4-5 moments that encroach peak. Like OP, the peak isn't just one instrument. It's a combination of transients (drums, piano, etc) during the loud sections that comprise massive energy once I have the song at the appropriate and desired level.

It's not as simple as turning the master down, because then, the quiet sections are too quiet. I've went back into the mix, and tried to lessen the elements that I know are contributing to the problem, but then I lose the intended 'mojo' of those sections. I do not like the sound of manually riding the fader during those sections during the mix, or the master. The peak is too small to catch that way.


The thing is, I have the song the way I want it. Quiet sections are perfect, loud sections are full of energy (without sounding loud), but there are still those micro moments of peak!

I tried Ozone limiter, to catch just those peaks. Peaks went right through Ozone 'intelligent' and 'brickwall', gee thanks. Peaks actually went through with a clipper AND Ozone (before and after)! (I know this isn't a smart thing to do, but at this point those 4 peaks are really on my nerves)14 day Demoed the UAD precision limiter, and it kept me in green all the way through.. with a even couple more possible dbs, which I refused. I don't see how I could have done it without UAD limiter.

I just want to be clear. Limiters should touch only peaks that cross your threshold, right? Are they indeed coloring an entire spectrum? I couldn't tell, however I probably don't have the ears of an ME.

EDIT: I understand all about the loudness war, but lets not jump to the conclusion that every person involved with music has a goal to be the loudest. Enough of the sarcastic "i know it's hard to pull the master fader down"

[Bob Olhsson]

The problem is that you can't know how best to choose or much less set a limiter until you know exactly what the final level of the master needs to be.

Some instruments like congas can sound a lot better with some peak limiting which is when it should be applied. Limiting stuff in a mix that doesn't make a profound improvement is pointless and could easily work against the sound of the final master.

[dave-G]

Well, to the original poster, and perhaps by extension .. to mr. smoke .. I've had a few clients who felt they didn't like the sound of backing down their master fader -- but it was because they were already mixing into a limiter by clipping the mix buss. Which is to say that the buss clipping is effectively a limiter on your mix! Removing it changes the dynamics of the mix! It can even change the dynamic response of the bus-compressor plugins that are inserted on the master fader (whose outputs can also conceal the buss' pre-existing clipping). Many people have no idea it's happening.

In s-cube's example, I don't know your software, but it seems a safe bet to propose that adding a limiter to your master fader is not limiting those peaks in a way that will avoid any buss clipping, rather, it's limiting what's left of those already clipped peaks, and at -0.2, it's just no longer pegging the little red light in the GUI. In ProTools (for example), bringing down the master fader is equivalent to bringing down the faders feeding the master ... and easier! Yours may be different, but have a listen.

Smoke -- in your case, if the problem is that your bus processing plugins change their dynamic response when you bring down the master, couldn't you just bring down your thresholds on those to accomodate the level lost in your master fader reduction and end up with the same mix + headroom?

Overall, if you're concerned about eliminating clipping in your mixes, you've gotta be aware of your gain structure and work for headroom while you're building the mix. Otherwise, you can try to back off the master buss until you have headroom, and process your individual tracks' dynamics, or add a limiter on the bus if you feel it is the way to make your mix sound right. In the end if you just can't find the mojo when the clipping is gone (on a mix you otherwise like), you can opt to live with the clipping. It would only be the hundred-millionth time that a mix has gone to mastering with peaks clipped already ... and while that's not great... well .. don't tell anyone I said so, but it's not always the end of the world.

-dave

[smoke]

Originally Posted by dave-G

Smoke -- in your case, if the problem is that your bus processing plugins change their dynamic response when you bring down the master, couldn't you just bring down your thresholds on those to accomodate the level lost in your master fader reduction and end up with the same mix + headroom?

Lets say the original audio is sent (aux) to 3 separate compressors. 50% of the signal is going into each compressor. I have thresholds set just to tame those loud sections, so I can bring the quiet ones up a bit. The 3 aux + original signal are mixed and routed to a master, which would be empty, but for the darn limiter which I didn't want to use! Anyway, the issue is that it sounds good! Not overly processed at all. If I go back in and mess around with thresholds, I'll make a compromise that really isn't better than just using the limiter (I think?)

Originally Posted by dave-G

Overall, if you're concerned about eliminating clipping in your mixes, you've gotta be aware of your gain structure and work for headroom while you're building the mix. Otherwise, you can try to back off the master buss until you have headroom, and process your individual tracks' dynamics, or add a limiter on the bus if you feel it is the way to make your mix sound right. In the end if you just can't find the mojo when the clipping is gone (on a mix you otherwise like), you can opt to live with the clipping. It would only be the hundred-millionth time that a mix has gone to mastering with peaks clipped already ... and while that's not great... well .. don't tell anyone I said so, but it's not always the end of the world.

-dave

Yeah, I guess that's where I went wrong. I wasn't careful about headroom in the 1st place. It was an experimental song, and was VERY dynamic. In order for me to create the contrast I wanted, some sections had to be loud. The thing is... the mix is nowhere NEAR peaking. I was caught off guard by the few peaks during the 'mastering' stage.

It's not that the mojo is gone without the clipping, it's that when I went back into the mix and lose a decibel on the trombone here, and on the stac harp there, bring the double bass down.... that ruins the mojo. The mix was fine.

I'd rather deal with a millisec of whatever happens when the limiter clips the peak! But now, I'm not really sure if I affected more than just those peaks.

Anyway, making the song was a great learning experience. You can learn A LOT by trying to do a classical piece, even if it isn't professional (even if I suck!). Pretty much every aspect of mixing comes into play.

[jamsmith]

I think what happened is when we first started mixing to digital (DAT), there was a big concern about "maximizing the bits". For some reason the soft passages that peaked at maybe -12db didn't all of sudden sound bad, but we were convinced you had to have every thing at -3dB. I remember running a mix and watching the DAT meter. Every time I saw -2dB, I would stop, run the tape back a few seconds, bring my master fader down a dB and continue. Lots of fun. Now that DATs just gather dust, I would assume everyone mixes to 24bits now. So why not shoot for a peak at -6, -9, or even -12 and worry about it hitting -3db in mastering?

I certainly agree with Bob on putting the limiter on the offending channel. Seems like my peaks were usually the snare so I would peak limit that channel.

Also, highlighting the peak in the wave editor and reducing the amplitude doesn't really fix the problem, you may not have an over, but you still have a clip. I know software can auto-fix that, but I don't have that so I use the pen tool and draw the clip out.

[s-cube]

Originally Posted by dynomike

Your logic that "If I don't deliver a limited mix, they'll have to limit it more in mastering and it will sound worse" is very much flawed.

You've misunderstood me too! Please read my post in detail, nowhere did i mention that i'm trying to limit my mix! I know the difference between mixing & mastering.

What i meant to say was that if i lower my faders the final RMS value of the mix will go down too. For example to control these random peaks i turn down the faders. Before the mix had a RMS value of -17 then it might go down to -19. So that will mean that when it comes to mastering the ME will have to limit the file more, right?

Anyway smoke understood perfectly what i meant to say, despite several people misinterpreting my posts!

I understand that the general consensus is to avoid it & i will do so. FWIW i'm using Cubase 4 & my concerns for lowering the master were to do with what i read a long time ago. Something along the lines of you lose 1bit for every 6db you lower it by? (memory's rusty!)

[ianshepherd]

FWIW i'm using Cubase 4 & my concerns for lowering the master were to do with what i read a long time ago. Something along the lines of you lose 1bit for every 6db you lower it by? (memory's rusty!)

That equation is roughly true (the issue is complicated by the fact that signals are audible below the noise floor), but is only really important if you're working at 16-bit. Using modern gear at 24-bit resolution, "loosing" one or two of bits ie. 6-12 dB of level won't make a noticeable difference to the quality.

One genuine concern is the internal mixing structure of the application, though. In some older apps I've seen, pulling the master fader down will stop the meters hitting zero but not prevent the damage. Luckily there's a simple test - set up a mix so say you are clipping the master output by 6 dB ( say ) and pull the master fader down by 12 dB. If you see peaks going up to -6 or above, then all is well. However if the output meters stop at -12, then the app is clipping internally before the output fader and you will have to pull back all the individual channel faders. The same test can be used for busses, if you're using them.

Hth,

Ian

[Boomshanka]

Originally Posted by s-cube

What i meant to say was that if i lower my faders the final RMS value of the mix will go down too. For example to control these random peaks i turn down the faders. Before the mix had a RMS value of -17 then it might go down to -19. So that will mean that when it comes to mastering the ME will have to limit the file more, right?

No, not necessarily. Peak limiting and/or clipping is by no means the only or best means of getting the final product hot enough for a particular sound.

Just do what you need within the mix, for the sound of the mix. In mastering, certain analogue path gain staging or some real subtle and judicious compression or upwards compression to raise a recording's inner detail can do wonders without sacrificing natural impact, often post any (real high quality) corrective EQ in mastering, however slight.

All in all, concern yourself with the sound - obviously there can be both detrimental effects from undoing your hard worked on mix balance's "mojo" or from the occasional peak limit - or from avoidable overloads - within the mix.

Overall, if you're concerned about eliminating clipping in your mixes, you've gotta be aware of your gain structure and work for headroom while you're building the mix.

Yep. And at 24 bit, and retaining bit depth all the way through the mixing process, worry not about using a few less bits in the final signal, for 'tis far outweighed by the benefits of a sonically good mix... with its mojo intact.

[fooman]

I often have mixes that will clip at the master, and it's usually the drum buss that clips during snare flams or something like that. I take all my busses and turn down.

I usually put an limiter on the master when mixing just in case software glitches take place or I have a slip of the hand and my speakers are damaged. If I see that my master meter hit -0.1 then I know the signal would have clipped. I usually check my headroom after a little bit here and there so I know what I'm dealing with at the master buss. When I want to render the mix out, I test it w/o the limiter.

However, I've always read that you shouldn't touch the master fader. Now I'm reading that it's ok. What's the arguement against using the master fader in a DAW? Does it truly matter if you pull down the fader to let the transients through rather than pulling down all your buss groups?

[smoke]

ericzang @ 7:30AM April 30th:

I can see your useful post on my Blackberry, but not here in the forum ?

Assuming it got deleted during the downtime, and if I have time... I will copy/paste it back in. It's great info, thanks.

[ericzang]

yes, looks like it got lost in the downtime. Thanks for trying to paste it in here if you get a chance!

for the other readers, in summary, I wrote that you can do a "null test" (invert the polarity on one mix) between the untouched mix and the exact same mix but with a limiter on it (make sure they are sample aligned and at the exact same volume). Then you can hear what the limiter is doing, or not doing, to the audio. I found ozone's limiter to null completely with the original until the peaks were being limited, which then I heard only short bursts of sound. Therefor, I am confident that the limiter is not changing my sound except for the peaks.

[smoke]

Originally posted by ericzang 4-30-08: Here is the message that has just been posted:
***************

s-cube:
all the limiter would be doing is reducing these peaks. However now i realize that even if it is only doing that it might still be adding color to the track so it's better to fix the mix by lowering it instead.

Originally Posted by smoke

I'd rather deal with a millisec of whatever happens when the limiter clips the peak! But now, I'm not really sure if I affected more than just those peaks.

As I deduce, you can run a null test to hear what effect, if any, a limiter is having on your mix. For example, you could take an un-limited mix and duplicate it to another track. Make sure they cancel to complete silence when you invert the polarity (phase).

Put your limiter on the second one and listen to the results (make sure they are still volume matched). I have found with Ozone that I continue to have complete null until it limits a peak. At that moment I hear an extremely short burst of sound.

Also I have found that when I lower the threshold of Ozone's limiter and the auto-makeup gain is engaged, I can increase the volume of my un-limited track to acheive complete null again, except for the peaks of course.

By the way, I do not have problems with peaks getting through ozone's limiter in intelligent or brickwall mode (note that peaks will come through while adjusting parameters though).

Another by the way, the RMS meter in Voxengo Span (free) has K-20, K-14, K-12 settings. It's been interesting to load commercial mixes and see where they average out to. It's been nice to see some of my favorites from the 80s range anywhere from K-20 to K-12. For prefinal mixes, recently I've been shooting for approximately K-14 (as long as the limiting action is still conservative