Reference tone for broadcasting help...

[antiphase]

I have this issue at work with applying/adding 1k test tones to a finished master to submit to a TV station. When some of our editors are done with their projects.. they end up scooting the project to the right a bit in the time-line so they can drag down a bars and tone generator from FCP's or Premiere Pro's generator lists. Once they have that in place they just seem to make all their music, voiceovers, and sound fx levels seem consistent with each other and then be done.

Now, what I don't get is, what's the purpose of them putting in the 1k tone when they have adjusted their audio levels to whatever monitoring (listen back) level they were using during editing? The 1k tone in FCP seems to be set at a default of -20db(fs?). So if the TV stations get this tape and calibrate their playback systems to this tone, and then the RMS or peak of the project is well above -20db(fs?) then that's going to be way louder than perceived.

So in a nutshell, how is the 1k tone supposed to reference the audio in the project? Is it to represent the highest peaks in the project at 1khz to -20db(fs?)? Or is it a RMS average? I'm trying to fix the audio inconsistencies of projects being broadcasted by knowing how to properly and accurately set up the reference tones so the TV stations can reproduce them correctly.

[Chief Technician]

This thread may be of some use to you.

[antiphase]

thanks for the link. There was a post that was starting to bring up what my issues were about editors not using test tones correctly, but didn't go into more detail. From what I read though, it sounds as though the tone is used for a "best guess/average" calibration, and not a 100% accurate formula? The tones are to give the editor a listening and metering reference to gauge a mix; and for the broadcaster to trust to correctly calibrate their playback for audiences?

[Chief Technician]

From what I read though, it sounds as though the tone is used for a "best guess/average" calibration, and not a 100% accurate formula?

The tone itself is supposed to be 100% accurate in and of itself. That is, a 1kHz sine tone at -20dBFS = 0 VU. As for the "best guess/average", its an average, not a guess. If an audio mixer has VU meters calibrated to -20dBFS = 0 VU at 1kHz, then the audio mixer should be mixing the program such that the average of the program is 0 VU (or close to it).

The tones are to give the editor a listening and metering reference to gauge a mix; and for the broadcaster to trust to correctly calibrate their playback for audiences?

Yes. If the mixer mixes the program so that it averages 0 VU, then after aligning the tone on the meters, the mix should sit confortably in the electrical signal chain.

[georgia]

side note: By default FCP tones are -12 not -20.. so that can also screw up things if an editor just "lays in tones".


cheers
geo

[RobMacki]

By default FCP tones are -12 not -20

Does that mean FCP is calibrated to -12 for 0?

[georgia]

FCP uses digital PPM meters so -12 is -12 on their meters. If you fire up FCP and drop tones and bars on a track you will see -12 on the meters. I've seen editors just drop tones and bars in and assume its' -20 so if a tech loads up the materal later and sets the tones to -20, your mix is 8 db too low.

cheers
geo

[antiphase]

side note: By default FCP tones are -12 not -20.. so that can also screw up things if an editor just "lays in tones".


cheers
geo

Looking back at my post, I'm not sure where I got -20 from. I think I got that mixed up with the default settings of PT's signal generator, my mistake. Thanks again for the replies.