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Greetings,

I've been wondering about this for a while and after a fireworks recording session last week I thought about it some more. So where better place to get some wise answers than SSD!

When recording in the field, whether it be collecting ambiances, effects or location recording for a shoot, how and when do you use limiters on your inputs? It may seem like a stupid question, but shouldn't you ALWAYS use a limiter to avoid distortion? If so, why do we have the choice to turn a limiter on and off - why aren't they just active as standard? Are there times when distortion is desired? Even if there are times when a distorted recording is required, why do all recorders have the limiter defaulted to off? Surely it would make sense to have it on and give the user the option to switch it off.

Maybe I've just not got it but as an old wise teacher used to tell me, no question is a stupid question! I'd love to hear you're views and opinions.

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5 Answers

I'd say it's a question of knowing what you're recording in this case...because, no, I don't always record with the limiters on. I've heard some do some funny "pumping" in the past that were spawned by restrictions in mic placement (yes, even on higher end gear like a Sound Devices 302...that was a shocker).

You shouldn't always fear distortion either. Think of it as another tool in the arsenal, rather than the worst scenario. You wouldn't use a hammer to drive a screw, but it works perfectly when you're driving a nail. I did some recording at drag races a year ago, and there was no stopping distortion. Those things were so loud that it was occurring at the mic in some instances. It fit the character of the sounds I was recording though, and added some extra color and gave a greater sense of the power in those vehicles than I would have captured otherwise.

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Good point with the pumping. That stuff can be hard to hear in noisy environments and with certain headphones. Limiter isn't always necessarily a lifesaver. –  Olle Sjöström Jul 18 '11 at 16:23
    
When the distortion occurs at the mic, is that dangerous for the mic's integrity? –  Chris Jul 18 '11 at 18:42
    
@Chris - I would think it's not great for it, but I'm not an expert on microphone diaphragm construction. We did what we could to reposition the mics when we realized that was occurring. There weren't any changes in their behavior after that recording session. So, they survived those momentary air pressure levels unscathed. Not sure what sustained might have done to them. –  Shaun Farley Jul 18 '11 at 19:09
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One thing to keep in mind is that limiters tend to affect the low end differently than the high end, so there are certainly situations where you'd want to "creatively clip" a big loud transient, especially if you have coverage with other mics.

I run with limiters on about 80% of the time (esp if I'm using the D50 limiter), and the other times I'm running limiter free as a pure creative choice.

24 bits is your friend, and cutting soft works.


edit:

I'll also add that knowing where your limiter is and how it works can be highly influential in the decision to turn it on or not. analog opto limiters on the front end of a nice mixer sound dramatically different than the digital limiters that show up post a/d on an H4 for example. Also, the PCM D50 doesn't "limit" as much as run a parallel insert, which I tend to like depending on the source of clipping.

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What do you mean 24 bits is your friend and cutting soft works? Can you explain how limiters affect the low/high end's differently? –  Chris Jul 18 '11 at 18:41
    
hard transients with low freq content in them (explosions) tend to get thinned out by limiters, as lots of the energy is in the low range. by just clipping instead of limiting you're getting some midrange funk instead of low end clamping, which can be creatively better. –  Rene Jul 18 '11 at 19:57
    
also, cutting soft but at 24 bits yields tons of headroom, and you still get clean audio down low. Its amazing how much you can gain up something that was cut softly at 24 bits without detriment to the sound. –  Rene Jul 18 '11 at 19:58
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Hmmmm... My thinking would be that though manufacturers try really hard (bless their hearts) to build true brick-wall limiters into all of their products, there's maybe still a bit of a knee to the threshold. So it may end up limiting/compressing things that come really close, but never pass the threshold.

Presumeably, if you're good enough (theoretically of course) you could ride -0.5 without passing GO. Thus you'd get into the limiter's knee without getting above the threshold and the damned thing would positively ruin your otherwise perfect recording.

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I always assumed it had to do with battery life. If you are recording something relatively quiet with a reasonable level of control you can turn off the limiters and save on battery consumption and go a lot further into the session before changing batteries or recharging. On the occasions when control in more difficult or the sound source is loud, go ahead and pop the limiter into the chain and let it do its thing, while knowing you will be draining the batteries at a faster rate.

Could be wrong on this but that was what I have been going with when deciding if I should engage the limiters or not.

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Great answers so far. Really interesting to see everyone's take on it. It's clearly somewhat of a grey area and I guess they need to be used and applied where and when necessary. Seems that there isn't really a black or white answer. But I'd love to hear more if anyone else wants to chip in.

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