Limiters

scorsesefan

scorsesefan

Veteran
Sorry if this has been asked before (I tried a search but couldn't find a good answer)...
I've never really used limiters in recording before because I've never had a (relatively) decent recorder but I just picked up a Zoom F8 and the limiters are supposed to be pretty decent. Do you guys generally use limiters in the field? If so what are some general settings you can recommend i.e. threshold, attack, etc. I know it varies, but generally recording dialogue (somewhat unpredictable run n' gun documentary) but plan on recording some music...

Thanks
 
A limiter by definition will always cut into and take away from the realism of your sound source. It's only a matter of "how much".

Any limiting done to a track can never be un-done. Once dynamics have been tamped down there is no way to realistically recreate them.
On a field recorder they are there to prevent audio from being destroyed by sudden unexpected volume surges that would go into fully-destructive clipping.

My goal is always to use as little as is possible - preferably NONE - which is generally only possible if you can audition or "rehearse" the sound source prior to recording. On a controlled set with scripted dialog I try to make sure the limiters are almost never being triggered. ENTIRELY possible.

From there on down everything else is a compromise.

Limiter thresholds are something that should have a lot of attention paid to them - the only type of settings that one could consider "set and forget" or "universal" are settings that by definition will do a fair amount of peaks destruction (limiting).

The most important setting is your input gain. only after that is seriously parked as best as you possibly can should limiting be brought in.
My advice is to err on the side of a lower input volume. For generations we made it all work with analog tape that had a noise floor about a gojirion times louder than all the digital recorders do now. (Gojirion = Godzilla sized)
 
Thanks, Dane. I've never used them in the past and maybe I'll continue that practice because the F8 records safety tracks...
 
I pretty much always use limiters, but only as a safety net. Not sure how much my setup relates but I set uo the mix pre so that the limiters will keep the signal below -3 dB. I aim at keeping peaks below that so in 90% of the recordings the limiter never activates. But IF I get surprised when FX recording or an actor decides he needs to scream a line he whispered last take I'm covered.
 
scorsesefan said:
Do you guys generally use limiters in the field?
Click to expand...

I use a Sound Devices MixPre-D for most dialog recording. My limiters are never off -- always on. And I leave them at the factory defaults (after hours of experimenting, I came to the conclusion that SD was spot on). They activate a couple of dB before hard clipping, thereby making clipping almost impossible. You get heavy compression instead, which sounds a whole lot better than clipping. But this setting is well above the level I aim for "peak dialog", so in perhaps 95% or more of my sessions, the limiter is not activated.

This is as it should be IMHO. The limiter is a safety. If you're hitting the limiters, you are pushing too close to the edge. So back off. It really is just that simple.
 
The default limiter settings on the F8 are: Hard Knee, threshold -2dbfs, attack time 1ms, release time 200ms -- I suppose these should work?
 
I thought the limiters (being digital - as you noted in a thread back last September!) were not a strength of the Zoom F8, so not sure where you got that from: this has been borne out by tests compared to SD preamps/recorders, for example: so all the more reason not to rely on them and just back off, as Bruce says.

Cheers,

Roland
 
Throwback said:
I thought the limiters (being digital - as you noted in a thread back last September!) were not a strength of the Zoom F8, so not sure where you got that from: this has been borne out by tests compared to SD preamps/recorders, for example: so all the more reason not to rely on them and just back off, as Bruce says.

Cheers,

Roland
Click to expand...
I was referring more to their place in the chain rather than the quality of the actual limiter...
 
Sound Devices mixers have both input and output limiters. ( see quote below from the MixPre-D manual )

The MixPre-D Limiters act solely as “safety” limiters. Activate the Limiters using the front panel “LIM” switch. Both input and output limiters are active, with input limiters preventing overload of the input stage and output limiters preventing the MixPre-D from overloading the next device in the signal chain.

In normal operation, with a properly set gain structure, the limiter threshold is only occasionally reached. In the presence of extremely high input signal levels, such as in high SPL environments,
the limiter(s) activate to prevent the input signal from clipping. The limiters have no effect on audio below the set threshold.
Click to expand...
 
at 4:44 he has the limiter set to threshold -6dBFS, soft knee, attack 1ms, release 250ms. i guess you can play around with it and yell into the mic to see if you can find better settings.

 
ugafan said:
at 4:44 he has the limiter set to threshold -6dBFS, soft knee, attack 1ms, release 250ms. i guess you can play around with it and yell into the mic to see if you can find better settings.

Click to expand...

-6db might be a little aggressive.
The default of -2db should be fine in most conditions...-4db if you're really unsure about what kinds of sounds might be coming your way.
The safety tracks are always a better choice if you are in a position to use them.

And yelling into it and hitting the limiters hard will show you exactly why you don't want them unless it's to protect against total clipping distortion.
 
We have run tests of an F8 vs. a sound devices mixer in the studio and the sound devices definitely has better limiters but we chose to go with the Zoom F8 because it was much easier to mount to our camera rig. To the untrained hear and to 99 percent of clients they won't be able to tell the difference. We also don't have a dedicated sound guy on set ever. We usually are running a two man band so sound has to be simple and yet still clean. I think that the difference (aside from the technical) comes down to what your budget is and what the project is.
 
There's one part of this discussion that's been left out - POST.

As an experienced audio person, I ASSURE YOU that I can do far far more with your dialog/audio tracks if they are simply recorded a bit low but not limited than I can with tracks that have hit the limiter hard enough to cause either a). audible limiting effects like squash, or pumping or breathing.. b). significant natural dynamic range loss.
All those negatives effects of limiters are permanent. Really cannot get them out.

But noise-floor hiss? "Scoop of vanilla, scoop of chocolate, don't waste my time.."

Any continuous static (unchanging) noise like the noise floor of WHATEVER half-way decent digital recorder you have is FAR less of a problem than it ever was in the past.
Not only is it pretty easy to eliminate most of that, but it's generally STILL quiet enough that if you have ANY other audio tracks gong on at the same time in the production, then it gets almost entirely masked out anyway.

Street ambiance of an outdoor scene.
Music tracks.
Any other sound effects or naturally occurring sounds in the scene.

These will almost always mask at least half of any noise-floor noise you may have on your tracks. And that's without doing any cleanup to them at all.

In a nutshell - you want to think of your limiters on your field recorder the way you think of those vibration-grooves they cut into pavement on the edges of highways to let you know you've reached the edge of the road - it's not a terrible thing that you hit them, but you sure as heck want to do it as little as possible.
 
"In a nutshell - you want to think of your limiters on your field recorder the way you think of those vibration-grooves they cut into pavement on the edges of highways to let you know you've reached the edge of the road - it's not a terrible thing that you hit them, but you sure as heck want to do it as little as possible. "

Nice comparison...
 
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