Front bass reflex acoustic systems
prices on 328 models— acoustic systems in which there is a phase inverter (FI; see "Acoustic design"), displayed on the front wall of the speaker. Most often this is the only FI, however, in some models it is supplemented by an air duct with a rear or lower location (see the relevant paragraphs).
This arrangement is the most versatile: if a speaker with a rear bass reflex cannot be installed close to the wall, then models with a front location do not have such restrictions. And from an acoustic point of view, we recall that it is impossible to say unequivocally which option is better — a lot depends on other design features, as well as on the personal preferences of listeners. However, a couple of nuances can be noted in this regard. On the one hand, from the front phase inverter, the sound enters the listener without reflections and distortions (unlike air ducts with a rear and lower location). On the other hand, this arrangement option does not allow experimenting with sound coloration by changing the distance from the speaker to the wall (as is available for models with an air duct outlet on the back of the case).
Note that the columns where the front FI is supplemented by the back one are deprived of the last drawback. Also, this design further improves the acoustic properties of the system. And the combination of the front air duct with the lower one is used solely to improve the sound — in such models there is no talk of additional tuning. At the same time, in both cases, the presence of two phase inverters affects the dimensions and price of the speakers, while the real need for such equipment is relatively rare. Therefore, this option has not received much distribution.