FCP’s audio meter

[Larry Asbell]

You know that CDs are mastered at a level that uses all available headroom. Think about what that means. It means there are no higher levels on the digital audio scale. There is no numerical value to represent anything hotter than that (insert reference to “This is Spinal Tap” here).

If Final Cut, Avid or any other audio mixing system worked at that level you simply COULD NOT mix the volume of anything further up!

You wouldn’t like that.

So, long ago designers of audio production systems set the working level inside these systems to be lower than that. The mix faders on both Final Cut and Avid allow you to turn any sound up 12dB. It may not be documented anywhere but isn’t it obvious that the capture process must drop all audio levels -12db or else there wouldn’t be anywhere UP to go? For some reason they didn’t design it to also drop the level of audio on import. And so you and everyone else has to.

P.S. I remember the very early versions of Avid Media Composer (about 1993) that could not mix audio any hotter, only lower.

[Walter Biscardi]

[Carsten Orlt] “For years I read that you should NEVER trust the waveform/vectorscope in FCP and always should test externally.
“

Not from me. The FCP scopes and now Color’s scopes are all we use. We’ve been delivering broadcast masters since 2001 and HD Broadcast masters since 2004 / 2005. The FCP scopes are accurate to about 1 or 2% and if you know that, you can adjust accordingly.

[Carsten Orlt] “Now you’re telling me to 100% trust the audio meters? “

Again, this is what we do. We trust the FCP meters for the mix and we’ve never seen anything change when we lay out to tape. The levels we see in FCP is what our VTRs show us when we’re laying back to tape.

And with over 100 HD Masters delivered, we’ve never had a show rejected by a network or video or audio issues.

Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.

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[Jeremy Garchow]

Thanks for doing this. This helps a lot.

Okay, this is a typical mix for CD (and not broadcast) that goes RIGHT up to the point of clipping but falls short. If you play the clip in a timeline, you will notice that the little red clipping lights don’t turn on (in this example that you’ve posted anyway). So, for this track, you could bring the level down to -10 and the level will be ‘right’ to broadcast. Or, you could call the audio post house and have them give you a broadcast mix.

Jeremy

[Jeremy Garchow]

In an extraordinary piece of timing, I saw this in an RSS feed today:

https://www.turnmeup.org/

[Isobel Knowles]

I guess I haven’t had enough experience with this. Every time I’ve dealt with soundtrack whether I have composed and edited the soundtrack myself or had someone work on one for me I have always just used a stereo pair in FCP. I would never contemplate mixing in FCP. It is not really designed for audio.

In Final Cut they put a line for suggested level and that is explained in the manual. I guess it just doesn’t make sense to me to have clipping lights when there is no clipping.

For the purpose of what I need to do today I think everyone has been very helpful letting me know about the -10db for broadcast. I will do that.

[Jeremy Garchow]

Are your clipping lights going off? Mine don’t go off in the sample you sent. If they are going off, you have inadverently turned up the level of that clip.

[Michael Gissing]

A moment of sanity please. FCP will output a digital stereo file at exactly the same level as the data on the file if it is panned L-R and the level is left a zero. I have measured this to an accuracy of .1db If the meters are showing clipping on a file mastered for CD, I am not actually surprised.

Meters can be calibrated to display clipping when a single digital word goes to zero. I suspect FCP is doing just that but don’t panic. It is done to warn operators of danger territory. Most pro meters are calibrated to show clipping when five words in a row do the same. I had a DAT machine that would constantly show clipping when other digital meters didn’t.

On the issue of broadcast levels, there have been heaps of posts that I have made about those so a search will answer all questions. I agree with Carsten that unless it is for broadcast no changes to the levels should be made.

To answer Larry Asbell’s concern – no FCP doesn’t drop levels -12db on capture. It captures at unity. The reason there is +12db gain is that location sound is often recorded very low and one of the most common threads here is how to make it louder than +12db

[Jeremy Garchow]

[Michael Gissing] ” I agree with Carsten that unless it is for broadcast no changes to the levels should be made. “

Michael, thanks for your post.

Can you please explain the thinking behind this? I guess I am struggling to find the logic in this.

Jeremy

[Michael Gissing]

[Jeremy Garchow] “Can you please explain the thinking behind this? I guess I am struggling to find the logic in this.”

If a file has been delivered to an FCP edit suite and it is a mastered final, then there should be no further tampering with it. For example, I often supply a mix that will be dropped into FCP before the final HDCam or digi master. If my levels are changed, then a tech reject is one possible consequence.

A pro sound studio should be the ones responsible for delivering a mastered file to the correct specs for that project. If you had spent hours grading a show and a dubbing house changed your peak whites by 1%, you would be livid. Similarly, we audio pros don’t want levels changed either.

[Jeremy Garchow]

[Michael Gissing] “A pro sound studio should be the ones responsible for delivering a mastered file to the correct specs for that project. If you had spent hours grading a show and a dubbing house changed your peak whites by 1%, you would be livid. Similarly, we audio pros don’t want levels changed either.”

I totally understand that and that’s why I love it when the mix gets back from audio post as it’s a drag and drop for me and it’s always mixed to broadcast spec. In this PARTICULAR case obviously the steps weren’t taken to ensure a broadcast level and Isobel was using a CD mastered file which can’t air in its current state and is not a file that has been delivered as such.

Let me ask you this. When you deliver a mix that has stock music in to serve as an underscore, do you call the stock music company and tell them to remix that track to a more acceptable level that you then can’t touch or do you simply mix the music and dialogue to your specifications by lowering the overall level of the underscore? Or do you only produce original music? In that case everyone should have your problems. Well wait, let me rethink that. If you DO produce your own music, do you remix/rerecord the entire song for the same scenario or do you simply adjust the level to make a broadcast specified mix?

Still the logic is failing me in Isobels’s case and if someone changed my overall white level by 1% it better be down and not up.

Jeremy