It always seems that when television commercials come on they’re a LOT LOUDER than the shows they’re interrupting. (Or is it the television shows that interrupt the commercials??)
Anyhoo, it seems that when the commercials come on I have to turn down the volume and then when the show comes back on I have to turn up the volume again.
Is this just a marketing strategy from the sponsors??
I notice that too, that is plain annoying. I still don’t know how they do that. :smack:
The peak volume of the shows and the commercials is probably the same. (I seem to recall hearing years ago that this was covered by regulation, but maybe only here in Canada. I could be wrong anyway.)
The shows rarely reach PEAK volume, mostly staying in the middle range.
COMMERCIALS, THOUGH, ARE mostly RIGHT UP near THE PEAK.
It’s not so much regulation as it is technical issues: if the volume is too high when broadcast, you get distortion. Ask any radio engineer about a VU Meter. 
I doubt commercials are a top volume, but they are usually above mid volume. However, the show might have cut away from a very quiet scene, or just dialog. The music of the commercial will sound louder even if it isn’t.
No, rjk has it right.
The regulations (both CRTC and FCC) dictate that the peak volume of advertising content mustn’t exceed the peak volume of regular content.
Because of this, audio techs working on commercials typically use compression so that all the sound on the audio is as loud as the peak level, which gives commercials a very brassy, attention-getting quality.