My experience with suburbia was that there was always yard equipment going, plus dogs and teenagers. These loud, punctuated sounds always bothered me much more than the regular, low din of a city. Moreover, most of the noise in cities in from automobiles, which are mainly a problem inflicted upon us by suburban development.
... and there are neighborhoods in the centers of cities, typically residential with little car traffic, that are very quiet.
Tokyo has a lot of these. It doesn't have a single "downtown", but rather a large number of busy centers, usually around railroad stations, and in many parts of central Tokyo, the "infill" between these is residential single-family housing or small apartment buildings. In many of those areas, streets are very narrow and windy, there's very little automobile traffic (people walk or bicycle), and it's often very quiet, to the point where one can sometimes hear people talking inside houses while walking down the street...
The biggest problem with Tokyo is a lack of laws against public disturbance in terms of noise people are allowed to produce.
All is fine and dandy until one of those stupid delivery trucks shows up near my building at 6am blaring "Hidari e magarimasu, gochuui kudasai. Hidari e magarimasu, gochuui kudasai. Hidari e magarimasu, gochuui kudasai". For people unfamiliar with Japan, various trucks here are not only equipped with visual (light based) turn signals, but audio based ones as well. This means that whenever they are taking a turn, they are blaring from their speakers "Turning left, please be careful. Turning left, please be careful" ad nauseam.
Seriously, is that really necessary? Not to mention trucks with loudspeakers playing loud music promoting new bands and what not. I find Tokyo to be anything but a quiet city.
To make things worse, sound proofing is so terrible in Japanese houses and buildings (construction standards are really poor here compared to the ones we have in the west), that despite living on the 6th floor I can often make out contents of the conversations of loud drunk groups returning from izakayas at 1am.
