Thursday, December 15, 2011

FCC calls for quieter commercials, but how?

In the news recently is the so-called "CALM Act" (Commercial Advertisement Loudness Mitigation Act), which will force TV and cable broadcasters (specifically, multichannel broadcasters) to make advertisements and content be the same volume.

The problem of blaring commercials, the TV equivalent of the loudness wars, have been going on for some time, but with newer technologies, including digital broadcasting, it has gotten worse. The fundamental issue is that advertisers want to be heard, so they want to be louder than their competition (the program material). However, it's not just a matter of submitting content with higher volume -- broadcasters, whether analog or digital, have limits to the maximum volume they transmit. Instead, they use recording tricks called compression and limiting to boost the average levels of their recordings while keeping the maximum just within limits. The result is a commercial that sounds louder that the program.

While digital technology has made it possible to take this loudness to an extreme, digital distribution has also provided one part of the solution: each piece of program material can be pre-marked with loudness information using a standard called A/85 rp which is used by the consumer's television to determine playback volume.

The trick is to accurately determine the loudness of the material, so that the A/85 tags can be correctly applied. As it turns out, this is no simple task. The ear is more sensitive to some frequencies than others, and you don't want to use simple averaging because then long periods of silence would allow commercials to get away with short loud segments that were disproportionately loud. To get around these issues, A/85 rp recommends the use of a well researched standard called ITU-R BS.1770 (which may be more familiar from the EBU metering and normalizing standard which uses it, EBU R 128). The ITU standard allows the measurement of loudness that very closely matches human perception of loudness, and offers recommendations for use in live, short and long form content.

Will the system be gamed? Perhaps content creators will find some way to trick ITU measurement system to make their content appear less loud than it really is, but even if they do, it seems unlikely that they will be able to game the system anywhere near as well as they currently do.

How will the FCC know if the system is working, and which broadcasters are using the system? They will rely on the public to call-in complaints. Of course, since this has, for years, been the number-one complaint they have received, I don't anticipate too much difficulty there.

Sunday, November 20, 2011

Let's Get Digital (Talk Slides)

Here are slides from my recent talk at the NYC Composer's Meetup. I started with a discussion of analog v digital processing, went on to discuss basic processing types (focusing on EQ, Reverb, and Compression) and gave some tips about usage. Finally, I explained how a simple mix might come together using these tools.

Talk Slides

Thursday, November 10, 2011

Slides from Fundamentals of Audio Programming

Slides from my talk on the Fundamentals of Audio Programming are available for download. They include the full slides and, for better or worse, my notes. Enjoy!

Also, someone asked about file formats, I said I would get to it, and I never did. If you are that person, feel free to contact me or leave a comment here and I'll try to send you some pointers.

Tuesday, November 8, 2011

Annoying Sounds

To an audiologist or acoustician it is not news that the ear canal has a resonance in the range of human speech, resulting in extra sensitivity in that range. I even remember my acoustics teacher musing about which came first in human evolution, speech with lots of content roughly around the 1kHz range or ears with extra sensitivity in that range (presumably with the advantage that an eardrum embedded in the skull is more protected from the elements).

To an audio engineer, the "midrange" frequencies are the aggressive frequencies. They're the ones you emphasize when your guitar or snare drum is wimpy, and the ones you take out if the mix is too harsh. Bob Katz, in his book Mastering, the Art and the Science, assigns the following negative subjective terms to describe excesses in this frequency range: boxy (400-900 Hz), nasal (700-1.2 kHz), harsh (2-10 kHz). My 21 year old acoustics text book states, "Noise with appreciable strength around 1000 to 2000 Hz is more disruptive than is low frequency noise."

Because the ear has different sensitivities to different frequencies, different "weightings" have been developed which allow measurements of sound level which take frequency into account. Some municipalities even take these weightings into account for noise complaints. These weightings date back as far as 1936.

Recently, musicologists studied what sounds are annoying. Their findings reenforce this old tale: sounds in the range from 2-4 kHz can be offensive. Even quiet sounds, like the classic fingernails across the chalk-board can be explained by a dominance of sound at these frequencies. What is interesting about this research is that it shows, for the first time as far as I know, that sounds can be made less annoying simply because of context. For example, if the listener is told the source of the sound is fingernails on chalk, they are more likely to say they found it offensive, than if they are told it is a part of a composition. Of course, it's possible they are just being polite, since either way, they have the same biological reaction.

Monday, November 7, 2011

Audio Programming Class

I'll be teaching a class on the Fundamentals of Audio Programming. This is  crash course (90 mins!) explains the basics of audio to software developers, with a focus on getting audio in and out of your computer.

Signup and more info at eventbrite.

Excitingly, we also got picked up by SonicScoop!