Loudspeakers are classified according to the frequency range they reproduce. There are subwoofers, woofers (TT), midrange drivers( MT) and tweeters( HT). The difference between woofers and subwoofers is that their frequency range is not as low as that of subwoofers and, above all, that their sound pressure is lower.
The frequency range of woofers, woofers, can not be specified in general, but only for a particular low-frequency speaker. In speaker cabinets, the frequency range of different speakers depends on the combination and frequency tuning with the other speakers: the tweeter, midrange and woofer. However, it can be stated that the frequency range of woofers starts at about 20 Hz to 100 Hz and goes up to 500 Hz.
Since the radiated frequency range depends on the volume that the diaphragm can move, woofers have a relatively large diaphragm area and a large diaphragm excursion. Both are directly related to the radiation of low tones, since the moving mass, which consists of the diaphragm weight and the weight of the voice coil, can only experience a certain acceleration due to the electromagnetic force.
The diaphragms have a diameter of 20 cm to 30 cm. Low-frequency chassis are built very robust because of the strong mechanical stress.