It wasn't so long ago that the obvious symbol of public-space decay and antisocial behavior was the flagrant use of the boom box. (For those who don't know what this is, or have forgotten, a boom box was an integrated music system, , incorporating a CD player, AM/FM radio, sometimes a Philips cassette player, plus 10 to 50 W stereo amplifier and speakers, all packed into a hefty unit roughly the size of a small suitcase.) Despite its bulk and weight, or perhaps due to it, teenagers and young adults in stages of arrested development would tote this unit, which often weighed in at 10 to 30 pounds (5 to 15 kg) and use it to signify their presence and pump out some pretty loud sounds. It was sort of like marking their territory with sound, you might say.
The net effect was to simultaneously delight those in the group they were with (if any) while seriously irritating everyone else. Due to their loudness and size (these units often took up their own seat on the bus) using boom boxes not only showed total lack of consideration for others in public places, but they also were outstandingly annoying. People nearby couldn't think, rest, or talk, and it wasn't just the volume itself: often, the music itself was pretty crude with vulgar lyrics (assuming you could actually understand what was being sung).
Pretty soon, legislators did what they do: they held press conferences, and then passed ordinances and laws which limited the allowable volume of these units to a more modest level, usually 60 to 80 dB at a distance of a few feet. Of course, there were practical enforcement considerations with measuring and ticketing offenders, but at least the authorities had some tools to use to shut these down. At the same time, the boom box users complained about their rights being restricted. Of course, the easiest solution of using headphones was not popular because it diminished the entire “in your face” aspect of having the boom box.
Fast forward to the last few years, and you don't see or hear much, literally, from boom boxes. Portable, personal players, first for CDs and now mostly using MP3-type formats, rule the personal-music scene. Carrying a boom box in a public space now would look just so “un-cool”, laughable, and even a little pathetic. The public is happy, users are happy, IC vendors are happy, everyone is happy, except for some sociologists who lament what they call a “retreat” into personal, non-shared spaces by individuals in public. (Apparently, these academics have never had the privilege of sitting next to a committed boom-box user on the bus!)
The enormous capacity and practical convenience of the personal player has pretty much made the boom box a quaint, antique product. Among the hottest product areas we see now from IC vendors–who, after all, make all this stuff possible and practical–are ultra-efficient stereo-headphone amplifiers, using Class D and even Class G topologies, targeted at personal audio systems. They know that's where the market is, and the boom box isn't it, except for limited, special situations such as providing a quick-setup audio system for a club or small dance floor.
Of course, in the world of style and fashion and trends, what goes around, comes around: perhaps soon, the boom box may return, somewhat upgraded, as a cool retro product. And just think: today's high-efficiency audio amplifiers and speakers, and relatively small size of the audio storage core, will allow for a smaller box with the same output volume, or worse yet, more audio output in the full-size boom ox enclosure. Maybe we should be a little afraid?♦