The front right view of the Sony SRS XB21 speaker.

Sony XB 21 Watts RMS

The XB 21 Sony Bluetooth speaker is a small to medium power, desktop style unit with sufficient audio watts RMS to fill a typical size room with full sounding tunes.

But what do the watts a wireless speaker has, tell us about how good it is?  Firstly, the watt is a measure of how much power the speaker consumes or outputs.  Plus, this metric is a nifty comparison measure. E.g. Generally speaking, speakers with more watts of audio output tend to play louder than those with less.  And while they do cost more, have bigger, heavier batteries and chargers, along with larger drivers and magnets, they nonetheless offer greater dynamic range, have a deeper bass response, and the models that do stereo offer typically a bigger soundstage and better imaging to listeners.

Picture of the Sony XB 21 speaker, connected and charging.
The Sony XB 21 speaker, connected and charging.

Thus in general, the more powerful the speaker, the better it sounds, even at lower volume. You get improved clarity due to higher accuracy reproduction of the bass, midrange, and treble musical content. More reserve power could mean less clipping distortion too. So, the speaker’s maximum watts RMS is a primary indicator of speaker quality and performance.  And as such, this value is of great interest to audiophiles and novice listeners alike.

In this case, the Sony XB 21, as a smaller wireless Bluetooth speaker, is a decently loud model for all the bigger it is. Its watts can fill a small to medium size room with clear music. See below for details on its power output.





Sony XB 21 Watts RMS: Details

    1. Battery Capacity: 11.34 watt-hours (3.78 volts, 3 amp-hours).
    2. USB Charger Power: 7.5 watts (5 volts at 1.5 amps), or 2.5 watts (5 volts at 0.5 amps).
    3. Light Power: Less than 2 watts.
    4. Bluetooth Standby Mode Power: Less than 0.3 watts.
    5. Power Bank Output Power: Not available on this speaker model.
    6. Total Audio Output Power on AC (RMS): 3 watts. *
    7. Total Peak Audio Power (both channels): 4.24 watts. *
    8. Output Power per Channel: 1.5 watts RMS. *
    9. Audio Output Power on Battery: Decreases as battery approaches depletion.

* = Estimated.

Sony XB 21 Watts RMS: Notes

    1. The system tries to conserve battery power as the battery get close to total depletion.  The XB 21 does this by reducing the audio output power somewhat.
    2. The XB 21 speaker may not input enough enough power from a low power USB AC adapter to keep the battery from discharging when playing at full volume, depending on what you’re listening to.  So it’s possible that even with the unit plugged in, you could still see it shut OFF unexpectedly.  Thus on the (rare) occasions that this occurs, just stop playing the 21 for an hour or two, to let it build up some reserve power while charging. Then, fire it up again for continued party enjoyment.

Other Sony XB 21 Posts

    1. How to Make Sony XB 21 Discoverable
    2. How to Reset Sony XB 21
    3. Sony XB 21 Not Charging Issue
    4. How to Tell if Sony XB 21 is Charging
    5. Sony XB 21 Blinking Orange Light

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References

    1. Official Sony XB 21 Support Page
    2. Where to Buy the Sony XB 21

Revision History

    • 2023-04-14: First published.