What does the clip indicator actually mean?

[davegibbon]

I am doing some "mastering" of a friends home recording. I know that shouldn't be dabbling in the dark arts but we're just doing simple volume increase and EQ balance.

I'm using the record to disk method because the BTD would always show clips. When I inspected the resulting waveform, I couldn't hear or see the offending area. Now that I'm recording to disk method, I can see the clip meter go off, and clearly the waveform isn't clipping and that area of the track sounds fine (to me).

What does the red clip meter actually mean?

And secondly, why isn't the limiter catching that peak and taming it?

Thanks in advance.

[albee1952]

The red means you have no headroom left. Anything above 0dbFS will clip. Regarding the limiter, what limiter is it and where do you have the output setting? I use Waves L2 with the output set to -.02.

[1ace1]

Davegibbon, you must try the Massey 2007 mastering limiter. Free to download. Great...!

With regards to clipping, unless submitting for broadcast, if you can't hear the clip then...... you can't hear it.

If this is the final stage (Master ready to be Pressed and Distibuted) then it should be OK. Remember that a clip when bouncing will not show up visually on playback, so always write down clip times when recording to disc so you can listen and analyse during playback.

A:)

[Kevin Kelly]

If you are still clipping you may have to adjust the threshold (when the limiter kicks in) and adjust the ratio (how much limiting takes place) higher. It works like this:
When the limiter senses audio above the threshold you have set it start to lower it by the ratio you have set. You are able to raise the gain because you have in fact given yourself more headroom to work with. Remember as you increase limiting you lower dynamics.
Good luck!

[davegibbon]

Thanks for the responses.

I was really scratching my head there for a while. The answer that I found leads me to more questions.

I had the limiter second last in the inserts. It was followed by the AIR stereo spreader plug in. So obviously, the limiter was doing it's job but the stereo spreader was casuing new peaks to be produced.

p.s. I downloaded the Massey L2007. Looks like another sale for him.

Dave

[arneal]

+1 on the Massey!

[chrisdee]

+2 for massey

[chrisdee]

Doing som A/B'ing last night between Massey CT4 and BF76 (comes with PT8), I heard a clear difference in the result in favor of the CT4.

At somewhat the same settings on the same vocal recording, CT4 enhances the signal while BF76 degrades is (atleast in this case).

CT4 was clear, open and transparent while the BF76 squeezes and cuts of ferquencies wich is not good.

[daeron80]

The BF76 and CT4 are very different kinds of compressors. Kind of apples and oranges. They excel in different areas. (Of course, a real 1176 is vastly better than the plug-in. And correspondingly more expensive per instance.)

Anything that follows a brickwall limiter is likely to result in some increased peaks, even if it's a "cut" type of thing, like a de-esser or even subtractive EQ. Especially subtractive EQ. Do some tests with white noise, square waves, and sawtooth waves at -6 dBFS followed by subtractive EQ of various kinds. Real eye opener.

Now DACs use low pass reconstruction filters. Subtractive EQ. The result will virtually always be peaks in the resulting analog waveform greater than the digital peaks. Sometimes significantly greater. So it's a good idea to leave yourself plenty of headroom. -1 or -2 at least. If you brickwall limit the final output to -0.5 or greater, you absolutely will cause clipping in the analog gear that reproduces it. Or if converting to mp3, you'll cause even more clipping.

Use the free TL Master Meter plug-in, post dither if you're dithering, because dither can add up to another 0.1 dB to peaks, and keep its oversampling level to -0.5 and you'll be clean. Even oversampling doesn't catch every peak that will occur in the analog domain.

[daeron80]

Another problem with maximizing to extreme levels is if your mix ever needs to be sample rate converted, overs will likely result.

So, to answer the OP Q more directly, What does the clip indicator mean? It means very little in terms of sound. It's a computer light, not an audio one. All it means is that one or more samples has reached 0 dBr (full scale). But the audio signal being represented can be up to 7 dB higher than the highest sample. 7 dB is rare but possible. Signal peaks around 0.75 dB above the highest sample are very common, even in fairly soft, clean mixes. Even in spoken word only. With hot-mixed, bright, compressed rock and pop, signals peaks 1.5 dB above are frequent, and 3 dB above are not rare. So, careful with that axe, Eugene.

Read the following and do the experiments mentioned, playing with various waveforms, eq types, and frequencies.
http://recforums.prosoundweb.com/ind...g/4918/0/48/0/