Question for Big Al

[Al Skierkiewicz]

Nobody said it was perfect. The act was actually introduced by a congress woman from California. It is surprising the history of this seemingly innocuous piece of legislation. You can follow some of it here...
http://www.commlawblog.com/tags/calm-act/
However, it doesn't really go into effect until next year (June, 2015) if all the wrangling with the FCC is finished by then. Under current guidelines, we are looking at LKFS which stand for Loudness, K weighting referenced to full scale. However, the weighting looks for average peaks over several minutes as recommended under ATSC A/85. Using that, one could adjust volume for dialog and live with loud noises or adjust for loud noise and be unable to hear dialog. At any rate, loud commercials or political announcements may not blast you out of the room when you have adjusted volume for listening to regular program. It actually works pretty well.

[DonRotolo]

I'm not a broadcast engineer (but I play one on TV!) but I used to be, sort-of. I was on staff for a TV manufacturer, so maybe a Receiving engineer?

Anyhow.

Ed Barker has it right: These is some dynamic range compression going on, so while the regular programming has a relatively large difference between quiet and loud, the commercials have only 'loud', boosting the sound during 'quiet'.

The commercial 'loud' is no louder than the regular programming 'loud' (thus in compliance with the coming regulation) but the 'quiet' is also somewhat loud. Advertisers do have to be careful to avoid annoying their (potential) customers however.

If you have an oscilloscope you can monitor the waveform voltages and see this. Use the slowest timebase you have and try to compare programming to advertising..

[Al Skierkiewicz]

Don,
ATSC A/85 accounts for that. The K weighting factor is looking at average loudness averaged over a period of time. The good news is that it really works. The bad news is that the originator is responsible to set it correctly while any broadcaster is tasked with maintaining the standard even if the originator didn't do their job. We get the fine, they may or may not. Satellite and cable operators must comply as well. This can be a big deal for them and the few that I have talked to are very concerned.

[IKE]

What type of TV do you have? I thought there was a particular model of TV that had a method for identifying, and controlling volume of commercials.

[DonRotolo]

Originally Posted by Al Skierkiewicz

ATSC A/85 accounts for that.

Yeah, well, my experience was with NTSC, now obsolete over-the-air. Stay current or become obsolete - a good lesson for today's engineers (and engineers-to-be).

Hey, if I remember correctly, it was you (Al) that killed Analog!

[Al Skierkiewicz]

Don,
That reminds me... That transmitter was a LARCAN manufactured in Mississauga, Ontario, just outside of Toronto. They were in the industrial park just to the west of the airport. Larcan was shut down by it's Chinese parent company, with no warning, in July of this year. The Chinese company had acquired controlling interest in 2009. The transmitter shown is still on the air. With the impending resuffle of channels mandated by the FCC, they will likely be relocated as will our Channel 47 transmitter that is just over 10 years old. Whether we will be able to continue to use it or not remains to be seen. I just read an article from a wireless microphone manufacturer that is calling for a investigation of the FCC rule making which plans to take away the wireless mic channels that are given clear use in current FCC band plan.