Resetting tone to -18 db??

Final Cuts video generator > PAL bars and tone - sets tone at -12 db. I never could understand why this is. I want -18db for standard British broadcast protocol. What is the best way to do this? Do I set it on the front of a Digi Deck? This is what I did and was peaking 1 db out. Do I change the setting on the timeline and hope it comes in at -18 db. I am used to computers and decks generating Bars and tone and leader black in presets like Avid media composer. In trouble..need help...Phil

Hello, Phil.
You can type -18 db where it says -12 db. You can also set the tone level in the Print to Video or Edit to Tape window, if you use that instead of the clip in the timelime (maybe a good idea, you don't need to place bar and tone on the timeline, since FCP will offer those mastering optiions when you print/edit to tape). In those windows, you also get a chance to test the tone level, to see how it peaks on your deck's meter.



Adolfo Rozenfeld
Buenos Aires - Argentina
www.adolforozenfeld.com

Phil:

Here's an old thread you may find of interest. There are a few like it if you do a search:

[www.lafcpug.org]


tc

-12 is the DV standard. It was thought that consumer equipment couldn't do the -20 US standard and still maintain an appropriate noise floor. It's been causing headaches ever since.

That's trivial. I want to know where you put the show.

In BBC PPM land, if the reference tone is at 4, then the show is expected to peak less than 6 which means in FCP a -12dB tone will give you a show peaking below -6dB.

It just so happens that's where US VU meters work ("zero" tone and the show peaking occasionally into the red).

If you move the tone to -18dB (I'll take your word on this), then the show should hover below -12dB or so, given a PPM's 4 dB per major division.

PPM Maximum Allowable Level is something like 6.3 or 6.4. That's the level where a technician comes out and smacks you.

Koz

Hey Koz, this issue's something I've been trying to get more knowledgeable on. What's PPM? Also, does it mean that a show mixed using -12dB tone with all levels between -6dB and -12dB, when being output to DigiBeta, should have all of its levels dipped by 8dB? Or does it mean that when setting audio input levels, setting the -12dB tone to enter the deck at -20dB should do the trick?

Oh, Fudge.

I can't do this now. I gotta leave for a while.

Kz

Mr. Kozikowski,

It would be great if you can elaborate when you find the time. This is still a little confusing for me. Perhaps for others as well.

In addition to the difference between digital and analogue audio, are there also different audio standards between PAL and NTSC?

I work in Europe and got an email from a TV station today. They wanted their DV tapes to peak at + 6 analogue or - 12 digital (for the show). Is this pretty much the standard or is there a lot of variation between stations?

Perhaps someone out there know of a good tutorial link about this subject?

Well, thank you for sharing.

Kim

Hey, Derek:

The above thread has some good info in it,as do these:

[www.lafcpug.org]

[www.lafcpug.org]

Get a cup of coffee and some hip waders...

tc

<<<does it mean that a show mixed using -12dB tone with all levels between -6dB and -12dB, when being output to DigiBeta, should have all of its levels dipped by 8dB?>>>

Yes, pretty much. As a fuzzy rule, the tone should be *about* 6dB lower than the show as measured on Peak Meters llike FCP and DibiBetas.

This isn't that hard, by the way. Play the tone in FCP on the above example show without adjusting the timeline and pull out the knobs on the front of the DigiBeta machine. Turn them so the tone settles at -20 US. That's it. You just created a standard DigiBeta tape.


<<<What's PPM?>>>

Peak Program Meter. The famous one is the one the BBC uses. It reads from 1 on the left to 7 on the right. It was a response to the shortcomings of the US VU meter. In BBC Land, that stands for "Virtually Useless."

The thing you notice right away after the black and white color of the PPM instrument and the markings, is the action. The PPM has a very fast attack time and a very slow release. This means the needle stays up there for a split second before falling back making it easy to read. It's personality is very like the FCP Peak Meters, except for the motion.

I bought the CEI Norme Internationale document on the VU meter because that's the one I was interested in building. The document for the PPM is enormously more expensive, so I passed.

However. In general, Each marking on the PPM is 4dB. If you place the reference tone at 4 (in the middle) then the show will be expected to wiggle roughly between that and 5-1/2 to 5-3/4. 6dB higher.

I am told by people used to using a BBC PPM, that it is expected that the operator rarely if at all actually touch 6, although that is technically allowed.

The Permitted Maximum Level (PML) is 6-1/4. If you touch that, the technician comes out with a rolled up London Times and swats you with it Very Hard.


I once saw the official instructions for using a PPM. It's frightening. Adjust a Male Voice so the sibilants peak....The Female Voice can be expected...Orchestra Crescendos....etc.etc.

The VU meter on the other hand, may not be a surgically accurate as the PPM, but it's easier to use. Tone at zero and adjust the show to wiggle roughly in the middle third.

If you push the above example show off to a Beta SP machine, again, pull the knobs out and adjust so the tone is at zero. The show should fall perfectly in the acceptable range of the meter. (Some BetaSP machines have other gymnastics you have to do to set the input volume. Consult your local listings.)

Please note that in all these cases, I made the recording machine happy *without touching the timeline*. A properly adjusted timeline can be adapted to any of these three instruments and recorders with a minumum of fuss.

Techie Disclaimers:

All these instruments can be faked out. They must be used intelligently.

The VU meter responds very roughly to show volume. If you, like us, need to make a demo reel with a bunch of commercials, the VU will tell you if one is significantly louder or softer than the others before your ears do.

The BBC PPM is *required* to be used with a high quality sound monitoring system. The speakers that came with your iBook need not apply.

I flat out don't know about this one. It wouldn't surprise me if the European Broadcast standard was -18dB Peak instead of -20dB peak. Call the station.

This one is sticky and I may try and find someone who can tell me for sure. The classic BBC PPM reads very unusually in the first and last segments. I don't know if they still do that. I won't go into that any more because if a lot of your show ends up in either segment, you're in doo-doo anyway.

Koz

*This is a pain in the YOU KNOW WHAT. I did it all on instinct and my show peaked at -9 db and I got wacked with a broadsheet newspaper for not peaking at -10 db. For the record, the BBC no longer accept DV unless you have a valid artistic reason. I was also told by a hire company tech that when the audio knobs on a digi beta deck are pulled out the signal is nigh on impossible to stablize, he said push them in and the preset sets the audio peak at - 10 db. News to me. I used to ride the online wave with an older deck with the knobs out using broadcast Avid or Discreet Edit and my online passed the BBC tech test. Now I'm in deep S**t with this whole thing using FCP 4.5. The PPM in the UK will make it up to 7 - over that and out come that newspaper again!
We need to stand tall and get to the bottom of this Apollo 13 scenario. To all you great people in the City of Angels - this ain't over yet. Thanks Greg, swing easy mate. Phil in Blighty

> Yes, pretty much. As a fuzzy rule, the tone should be *about* 6dB lower
> than the show as measured on Peak Meters llike FCP and DibiBetas.

True, true, true. I hadn't considered that the audio input controls on the deck are pretty much absolute. ("where x = -12dB, redefine x = -20dB, therefore x = x - 8dB"

This is what I don't get -- a post house we were working with called us last week saying our tone levels are wrong. Originally I'd thought it was because the office manager (who handles tape outputs) had used the FCP tone at -12dB without changing it, which I also do since I work mostly with DVCam and Mini-DV. But I also know that the boss calibrates the audio on the DigiBeta decks himself so that the tone enters at -20dB, meaning the whole show should dip by 8dB and be safe in DigiBeta land. So I wonder what their problem is?

<<<a post house we were working with called us last week saying our tone levels are wrong.>>>

You need to get them to explain exactly what they thought was wrong. In detail. There was a message here a while ago where a post house delivered a completely unmanagable show to the stations from a master that, as near as we could tell, was perfect.

That was when I said the magic words, "I want to visit the post house with a flashlight."

<<<*This is a pain in the YOU KNOW WHAT.>>>

I can guess what, yes.

Nobody has yet said the words, "PAL Standard Tone is -018dBFS." That's a big deal because everything else flows from that. If that's true, then yes, show peaks, in the UK, should be certainly no higher than -10dB--more like -12dB (6-ish higher than the tone) and the tape tone should be -18.

That should work out to PPM 4 for the tone and PPM 5-1/2, 5-3/4 for the show. Yes. If you sent them PPM 7, I'm surprised then they didn't come looking for you with guns.


<<< So I wonder what their problem is?>>>

We have a really cheap, bad VU meter panel that was calibrated incorrectly. Everybody knows to ignore it, but if you thought it was correct.......


<<<when the audio knobs on a digi beta deck are pulled out the signal is nigh on impossible to stablize>>>

Take names. All a DigiBeta machine does when you pull the knobs is thriow a data multiplier into the pathway to change the level. You should not be able to tell from the tape what was done.

If the person is complaining about wandering audio levels, that's Your problem, not the machine. I will check into this more.

Koz

If your doing broadcast work in the UK its a good investment to buy some PPM meters (i feel lost without them) also a good idea to get a tone test tape and line everything up with that.

I seem to remember we went -18 when digibeta first came out so we could have more headroom before that digital clip kicked in.

never had an issue with the knobs pulled out on the digibeta for a fine tune of levels.

<<<never had an issue with the knobs pulled out on the digibeta for a fine tune of levels.>>>

Nor have we. It's possible there's something broken. We've been running under the assumption that it's a human problem.

Koz