In-Wall speakers often used as the front 3 channels in a surround sound system as they can be discreetly placed around a large TV or even behind an acoustic projection screen. They can be used in single pairs or linked together in multiple pairs to evenlycover larger areas with sound.
The diameter of the bass driver is a common way to categorize the speaker, in a similar way that TV's are measured by the diagonal size of the screen in inches. Most in-wall speakers point directly forwards and have a swivelling tweeter to help aim the higher more directional frequencies to the general listening area. For installations where the sound needs to be “pointed" towards the listening position (for example when they are installed towards the edges of the room) models with a swivelling baffle are recommended.
The low frequency response (amount of bass) of a in-wall speaker always tends to be much less compared with the equivalent book shelf or floorstanding speaker. This is because the speaker does not sit within a specific tuned ported cabinet but instead has to operate in "free air".
A way to achieve a large full sound with a solid bass response is to use a separate subwoofer within the room. Surround sound systems will almost always use a subwoofer but stereo music speakers and also greatly benefit from the extra bass response. As the subwoofer produces only the lower end of the bass spectrum, which is unidirectional to the human ear, the bass will appear to come from the wall speakers. The subwoofer can be placed discreetly within the room, behind a sofa, under a side table or even integrated into custom made furniture.