A Question Of Audio Levels

[Tape Splicer]

Over the years we have had both Shaw and Telus TV provide our cable service. With both services we have had digital boxes. We have noticed that the audio levels during commercial breaks is so much louder than the programs themselves. It does not seem to mater which channel one is watching. I can't believe that it is as simple as bad audio operation at the station's end. There must be something more going on. Any thoughts or a simple explanation?

[jon]

Audio compression is done on virtually all commercials by the production company that created them. I've only ever heard of one TV show that bothered to do audio compression: the first Royal Canadian Air Farce episode on TV. CHUM Production guru Doug Thompson did that at the request of Roger Abbott, a former Top 40 DJ.

The type of Audio Compression I'm referring to is more like Automatic Gain Control or Automatic Volume Control in years gone by. Not the type of compression that makes computer files smaller.

Unlike Radio Stations, TV Stations do not have automatic audio level control in "the Audio Chain" on the way to the transmitter. Top 40 stations like CKLW ("The Big 8" in Windsor in the '70s) had very sophisticated audio control to make sure that, second by second, the station sounded consistently loud.

[Mike Cleaver]

If you are listening through a modern tv set's built in speakers, the problem will be less annoying.
Most modern sets have automatic volume control which you can set to "level" out the differences in sound volume.
However, if you're taking your audio feed from the digital boxes analog (RCA) outputs and running it into a home theatre system, you can add a compressor between the digital box and your home theatre audio system to smooth out the levels.
I've done this for years and it makes diving for the remote to turn the volume up or down a thing of the past.
The cable and satellite companies have the ability to control the audio levels and match them between channels but most won't bother.
The box I use is an FMR RNC or Really Nice Compressor.
About a hundred bucks.
You can get a much cheaper one from Behringer.
Sam Lee carries both in the Pro Audio section.

[freqfreak2]

Jon and Mike: you're both right but other skulduggery and sloppiness is in effect here.

My long-retired 1985 JVC HiFi VHS VCR had analog VU meters that indicated actual manual record levels (the machine also had an auto setting). In manual mode, I could easily see the difference in levels between cable channels, and between program content and commercials.

Yes, commercials use compression. But when I set program levels for '0' peaks, the commercials would then pin the meters. If it was a simple matter of compression, commercials should read a constant 0 db - matching program peaks. They didn't. That told me commercials are (purposely?) delivered louder.

Secondly, the whole point of digital was to improve dynamic range. For a consumer to retrofit and add compressors to the chain defeats that purpose.

Given how cable and satellite providers are trumpeting 'quality' high-def signals, why don't they even out the levels across their channel and program content range but leave the dynamic range alone. Seems to me if you can buy similar off-the-shelf gear at retail, the BDUs can do the same (and of course pass the cost on to consumers).

I don't want to wander into conspiracy theories here, but willfully blind (or deaf) seems to be standard operating procedure.

[Tape Splicer]

A follow up thought; Is not the FCC trying to regulate audio levels in the US television industry as a result of consumer complaints re: audio levels? Has this come before the "CRiTiC" here in Canada? and if so, what has "CRiTiC" said about audio levels in the television industry? Or might this be something the C-"BS"-C might make itself useful at sorting out???

[Tape Splicer]

It appears that the CRiTiC is going to address the audio level mater. This link is to the "Globe and Mail" article dated today titled "Turn down noisy TV Ad's: CRTC"



http://www.theglobeandmail.com/report-o ... le2164183/

[Tape Splicer]

This is the CRTC page which explains "Loud commercials and sound levels".

http://www.crtc.gc.ca/eng/info_sht/g3.htm

[DirkSteele]

Inserts in cable programming is probably a big part of that. The national feed and commercials come at one level and then the local inserts are another.

I've found that the regular broadcast channels are pretty consistent because they are sourcing all their own audio. It is the cable world where you get the big fluctuations. Food Network and Showcase are the biggest offenders in my books.

It might be more complex for operators than "run your audio through a limiter". Or...it is a big conspiracy to play the commercials louder. That's a thought for the other board.

[groundwave]

Although the loudness issue itself likely stems from the use of audio level compression and frequency shaping techniques during commercial soundtrack post-production, you have to wonder if one of the reasons TV broadcasters are unable to routinely deal with the effect in an audience-friendly manner may be the result of using peak as opposed to average responding metering throughout the station's pre-transmission audio chain. Back in the old analog days, average-responding "VU" meters (not unlike the one depicted in my avatar) were the gold standard. These indicated levels in a manner that far more closely reflected the way humans perceive loudness. The ballistics of these meters were purposefully sluggish, something they could get away with since analog amplifiers tended to overload gracefully and gradually. Today's digital audio systems have a very sharp "brick wall" overload characteristic necessitating the use of much faster "peak responding" meters. It stands to reason that the relatively compressed audio of a given "loud" commercial, will read far lower on peak-responding meters in spite of sounding comparatively louder to the ear. This is due to inherently tamer audio peaks riding on a smoothly boosted audio baseline. As a result, levels in the TV broadcast signal chain are prone to be calibrated in a manner that seeks to compensate for such a low meter indication. Any subsequent upward compensation could easily boost the voltage level by as much as 6 to 8 dB, depending on how aggressive a combination of peak limiting and compression took place during the production of the worst-case commercials. This 6 to 8 dB difference can be readily heard (duh!) and could easily pass through a typically "soft" final audio limiter set up to function primarily as overload protection for the transmitter's modulator. Under this scenario, the best way for a TV broadcaster to comply with this directive is to attack the problem at the stage closest to the source by inserting a (loudness based) dynamics processor into the initial mixing point where audio from commercials enters the station's chain. The audio output of this processor will, courtesy of the processor's action, exhibit a constant loudness characteristic. It should be adjusted to display a suitably low level (determined by comparative listening against other program sources) on any subsequent peak-responding monitor meters.

[jon]

I think you may be giving more credit to the sophistication of audio compression equipment than may be warranted. I once worked at a Top 40 station that had their compression very tightly done to give a very loud sounding sound. But it could lead to extreme levels of overmodulation for one reason: it controlled the level based on sounds at 1000 Hz. Anything with a lot of bass created terrible amounts of distortion thanks to overmodulation at levels way beyond that Industry Canada would fine them for.

Point being: that was Radio. TV's audio processing has typically been primitive in comparison to Radio.

[groundwave]

I don't know exactly how long ago your observation was formed Jon, but I really believe today's best gear is up to the job. That said, the "best" new dynamics processing gear is rather costly and many stations, especially those in smaller markets, may balk at going this route. Another approach may be to take radio's lead and simply use a more robust leveling/comp/limiting profile in existing equipment chained immediately ahead of the transmitter. Speaking of radio though, if today's cleanest sounding FMs can hold their levels in check, there should be no reason why TV can't ultimately do likewise. The time may have arrived for some TV plant engineers to start looking over their shoulders at how certain things are done in radio.