Max audio levels for broadcast for info

7 replies [Last post]
MAGLINK
Offline
Joined: Mar 8 2007

A lot of people ask what are the max levels for broadcast delivery in the UK so I did a short you tube clip to show the max +8 PPM:http://www.youtube.com/watch?v=CX14GmG17nE

1khz Line up tone would be 0db=-18dbfs=4ppm=-4vu=test on this EBU scale
Max broadcast level is +8db=-10dbfs=6ppm=+4vu=+8 on this EBU scale

Note that the Master 1 dbfs meter to the left of the PPM is not showing a level of around -10dbfs this is because the meter is pre final compression, there is around 3-6db of gain reduction before final output making sure that the levels never go above +8db.

Hope this helps.

PaulD
Offline
Joined: Aug 31 2002

Hi
I would guess that for NLE users without extensive metering options the "Max broadcast level is = -10dbfs" setting is the most useful.

MAGLINK
Offline
Joined: Mar 8 2007
PaulD wrote:
Hi
I would guess that for NLE users without extensive metering options the "Max broadcast level is = -10dbfs" setting is the most useful.

That is correct Paul but beware of meter balistics on full scale meters as in FCP etc some of them are very sensitive and you may be Ok on the dbfs meter but still over on the broadcast PPM.

Its not easy as even some of the chromatec and on screen meters that we use in pro are still not as good as an old BBC neddle PPM but if you peak as an average between -18 and -10 you should be OK.

Alan Roberts
Alan Roberts's picture
Offline
Joined: May 3 1999

Spot on, meter ballistics play a big part in this. The spec of the original PPM was based on a specific meter movement, and a lot of work went into characterising it.

Get my test cards document, and cards for 625, 525, 720 and 1080. Thanks to Gavin Gration for hosting them.
Camera settings documents are held by Daniel Browning and at the EBU
My book, 'Circles of Confusion' is available here.
Also EBU Tech.3335 tells how to test cameras, and R.118 tells how to use the results.

ChrisBitz
Offline
Joined: Jun 8 1999

Hope this isn't a silly question, but in Premiere, I have -6, -12, -18 and -30 on the guage.

is it on that scale that you say the max should be -10, or have I misunderstood? :-)

Thanks,

Chris.

Alan Roberts
Alan Roberts's picture
Offline
Joined: May 3 1999

Remember that the ballistics of the meter are irrelevant when you have a constant amplitude tone signal. And you line up the gains and meters using a tone source. So -10dB is always -10dB, whatever meter you measure it on, provided the source is at constant level.

Get my test cards document, and cards for 625, 525, 720 and 1080. Thanks to Gavin Gration for hosting them.
Camera settings documents are held by Daniel Browning and at the EBU
My book, 'Circles of Confusion' is available here.
Also EBU Tech.3335 tells how to test cameras, and R.118 tells how to use the results.

MAGLINK
Offline
Joined: Mar 8 2007
ChrisBitz wrote:
Hope this isn't a silly question, but in Premiere, I have -6, -12, -18 and -30 on the guage.

is it on that scale that you say the max should be -10, or have I misunderstood? :-)

Thanks,

Chris.

Yes Chris that is DBFS (decibel full scale) so 0db line up is at -18dbfs and MAX level for broadcast is -10dbfs (+8db)

As a side note when recording on location you should peak to around -12dbfs that way you get plenty of signal to work with and it also gives you 12db of headroom just in case anyone shouts:eek:

Rob James
Offline
Joined: Jun 26 2001

Feel I have to remind folks that in the US the standard levels are different. -20dBfs for 0dB line up and -12dBfs(+8dB) being the most common. (And used by Sony amongst others.)

Rob The picture is only there to keep the sound in sync