Sound quality: Sony's SRS-XB21 had fair overall sound quality. Bass has good impact but is slightly boomy and the deep bass is lacking. Lower midrange is subdued and mid and upper midrange is hazy and slightly grainy. Treble is smeared and upper treble is muted. Doesn't do a good job recovering room ambience, sounds congested and is lacking in detail. Bluetooth and wired sound quality are similar. Provides a decent volume level in a small to medium sized room but gets harsher at higher volume. When two units are used as a stereo pair sound remains hazy and congested, it can get louder but since two separate speakers are used the sound stage can be made wider depending on placement and room ambience improves to decent, sound quality remains fair. The stereo pairing setup is a tedious, ambiguous process which required a combination of button presses on both units.
Ease of use: We found the Sony SRX-XB21 ease of use to be very good overall. Volume controls are low contrast, there is nothing to indicate that it is a volume control except + and - symbols. Bluetooth pairing requires a press of a low contrast labeled and multifunctioned button which is also the power button on the unit and then the selection of the unit from Bluetooth selection list on source device; unit provides an obvious indication that the unit is in pairing mode as well as when pairing has actually occurred. Unit also has NFC capability. Switching sources involves plug and unplug - The line input has priority over Bluetooth when plugged in with slight or no delay. Unambiguous. Aux input label is low contrast.
