Friday marks the one-year anniversary of the implementation of a federal law that prohibits broadcasters from blasting TV commercials at volumes louder than the programming.

Whether the ban has worked depends on who you listen to. The FCC notes that formal complaints about overly loud commercials are on the decline (see chart), but they have totaled more than 20,000 over the past year ... and one expert says they aren't necessarily an accurate measure of compliance anyway. Anecdotal assessments are mixed, too.

Dubbed the CALM Act -- Commercial Advertisement Loudness Mitigation Act - the law authored by Sen. Sheldon Whitehouse, D-R.I., and Rep. Anna Eshoo, D-Calif., was passed in 2010 but only implemented by the FCC on Dec. 13, 2012. "Since our rules became effective, the Commission has received nearly 20,000 complaints involving excessively loud commercials," FCC commissioner Jessica Rosenworcel said last month. "By any measure that is a lot."

The latter is not universally held opinion.

"I'm very pleased that the loudness standards set in place by the CALM Act are working," Rep. Eshoo said in a statement. "Fewer complaints suggest that fewer TV commercials are airing at volume levels inconsistent with the programming around them. For consumers, this means they're finally getting relief from the earsplitting volumes of the past."

A colleague who says loud commercials drive him crazy insists that the problem has been largely eliminated.

But search Twitter and you'll find comments such as: "Whatever happened to the #CALM Act?" And "I thought @SenWhitehouse fixed the loud commercials thing with the CALM Act? Commercials on @CBS seem way louder than '60 Minutes' tonight."

Attorney Harry Cole of Fletcher, Heald and Hildreth, who specializes in broadcast industry law and has blogged about the CALM Act, says that the 20,000 complaints figure "doesn't strike me as very many, given the universe of potential complainants." It's "hard to say" whether the law has worked, he adds, though there have been benefits, even for broadcasters.

"Has the problem been solved? That's a tricky question, largely because the perception of loudness involves a complex combination of factors not all of which are subject to regulation," Cole says. "Loudness is often in the ear of the beholder, which means that programming that is fully in compliance with all FCC rules and guidelines may still be perceived by some individuals as 'loud,' which may cause those individuals to complain. In their view, the problem may not have been solved. But for the video delivery industry, the CALM Act does afford a useful way of defending against such complaints, so in that sense the CALM Act has helped resolve the chronic problem of seemingly 'loud' commercials."

Cole also notes that compliance in this case requires hitting a moving target, as the technical standards that by law dictate the FCC rules have already changed and may well change again. "My hunch is that these standards are under more or less constant development, which could mean more revisions down the line," he says.

And while that may signal alarm bells in anti-regulation circles, Cole says he hasn't heard much bellyaching from the industry.

"As far as I can tell, the CALM Act rules have thus far not had any oppressive impact on broadcasters," he says. "Of course, the Commission gave smaller operators - i.e., folks likely to feel the brunt of the new rules the most - some extra time within which to bring themselves into compliance, so we may not yet have a complete picture of the overall industry-wide impact, but so far I myself have not heard many complaints about the cost or other burdens imposed by the rules."

(Geek-Themed Meme of the Week Archive)

If you'd like more details about the CALM Act and how it works, the FCC has an FAQ page here.

And if you're still being jarred from your couch-potato slumber by excessively loud commercials, and simply want to let the FCC know, that complaint form can be found here.

(Update: I just remembered this caveat. If you are inclined to file a formal complaint with the FCC, be advised that trees will die as a result - or at least they did when I complained back in 2009 -- no matter what it says in the Paperwork Reduction Act of 1995. Of course, your experience may turn out differently, as it did for one long-time Buzzblog reader.)