[OT} Rogers: Very Loud Volumes for Commercials

[Peter]

The keywords to look out for are "dynamic compressor". This is a software or
hardware device which compresses the dynamic range of all programs. It is not so
good towards high fidelity in a home theater but it will save the day if you
have commercials blaring into the most unexpected and unpleasant moments of a
program. The normal answer is, to buy the edited copy which has no commercials
and the sound adjusted. 

But most modern HD boxes and even many TVs have the dynamic compression option
in the sound menus somewhere (sometimes it is called something else - do not
confuse it with "wide" stereo settings). I know that Rogers boxes have this in
the sound menu somewhere under "volume range" which can be selected between
normal and two more settings. One is narrow or so and actually means dynamic
compression.

In a nutshell dynamic compression will reduce the dynamic range of sounds from a
normal 45dB-ish in normal TV to 20-30dB. In HDTV it must work much harder and
reduce from 100dB to 20-30dB, often with unsatisfactory results. Turning d.c. on
is almost mandatory in TVs placed in noisy public places and I wish the PA
systems on TTC and other public places where it is really important to
understand what is being said would know about this.

Studio reprocessing of programs often applies d.c. of some kind, especially when
the original program was mixed by some ham-hand or deliberately tweaked to
"accommodate" advertising. This often requires several seconds of delay for
real-time processing, to avoid volume jumps. MythTV and such likely do this and
it works but as others have reported getting rid of what was implemented in a
well-proven way in a studio is very hard.

In my experience programs meant to be broadcast over cable or air with ads
"added in" have the sound levels deliberately reduced. Most original programming
comes mixed and set up for -3dB to -6dB audio, to allow for peaks (most
professional equipment, like Beta, DV and SVHS players have more than 10dB
headroom, i.e. +10dB signals won't distort). Lower sound setup settings are not
used because subsequent amplification would bring the background noise up into
hearing range and cause the program to appear of lower quality. So the studio
techs are explicitly told to lower the sound setup on the program deliberately
to -10dB or even -15dB to accommodate the advertising. This is not nice. On many
programs mixed like this one notices that one has to increase the volume quite a
bit to hear normally and that background hiss is somewhat noticeable (not on
digital programs though, that's one of the tricks digital programming has,
hiding the noise completely). As expected, the inserted ad sequences are
ear-ripping, often a full 20dB (10 times) louder than the program material and
already dynamically compressed and pre-distorted. On a normal TV this will
overdrive the speakers and it will sound buzzingly loud. In a home cinema
setting it could wake the dead and break windows. It could also destroy sub-spec
speakers and shakers if left to go on long enough unsupervised.

What was common practice for perhaps 30-40 years in TV and radio advertising
will now have to go back to less aggressive settings because home theatre owners
will not react positively to thunderous house-shaking advertising, as the
original poster noticed. So, again, the "best" solution is to get a recorded and
re-mixed copy and watch that. Complaining will not help much. Stations got away
with stuffing advertising into anything and charging premium prices for them on
top of that. One of these things will have to go, by legislation. Either premium
priced programming with no ads, or low cost with ads, but with technical
standards which are acceptable for the equipment in use.

  Peter (electronic tech)


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