Picture of the -BATT- button on the Sony SRS XB21 speaker.

Sony SRS XB21 Buttons Explained

The Sony SRS XB21 Bluetooth Bluetooth speaker has several buttons across its top panel, including the Volume, Phone, and Power-Pairing buttons.   We also have the ResetLight-Batt, WPC, and Add buttons at the rear of the unit inside the port compartment. These buttons you use to access the many features of this portable but big sounding speaker.  So here we offer our  Sony SRS XB21 buttons explained help guide.  E.g. We show you where each control is on the speaker, explain its meaning and function, what any button combination presses do, when to press them, and how to use the buttons to operate the speaker in general.

Sony SRS XB21 Buttons Explained: Top Panel Buttons

There is one row of buttons on the top of the speaker. They each have unique shapes. Furthermore, there are two lamps on the top button panel, and three more in the rear port compartment. The lights tell you what the speaker is up to.  The Power lamp lights up white when the speaker is ON.  The Pairing Status lamp lights or blinks blue to show the current speaker connection state Plus, there’s a CHARGE lamp on the back of the unit that flashes when the battery is getting low, and glows steadily as you charge the speaker.  Also back there, we have the ADD and WPC lamps that glow when either of these modes is active.  And finally, there’s the micro USB charging, and auxiliary (AUX) input ports.

The Power / Pairing Button

The Pairing / Power button, near the right top edge, as we point out with the cyan arrow in the next picture. Note its power symbol  shape.

The -Power- button on the Sony SRS XB21 speaker. Sony SRS XB21 Buttons Explained.
Sony SRS XB21 -Power- button.

Turning the XB21 ON and OFF

Press and release the button when the speaker is OFF, to power it on.  Press and release it again, to turn the 21 back OFF.

The Power Status lamp lights up when the speaker powers up, as we see next.

Picture of the glowing -Power- light.
The -Power- lamp glowing.

Plus, the speaker makes a two-rising-beeps sound during booting, and two-falling-beeps sound when you switch it off. Furthermore, it plays these beeps whether or not it automatically pairs with a device upon startup.

When the speaker is OFF, no lights on it should glow, except in the case where you’re charging the unit.  When OFF in that scenario, the CHARGE lamp still glows solid orange.

Picture of the -CHARGE- light glowing.
The -CHARGE- lamp glowing.

Finally, the Bluetooth Status lamp illuminates in one of three possible patterns.  1) It slow blinks when the speaker comes up in standby mode, ready to pair but not in discovery mode.  2) It fast flashes when the speaker boots into discovery / pairing mode.  3) It glows steadily when the speaker establishes a connection with a source device.

The glowing -Bluetooth Status- light.
The -Bluetooth Status- lamp glowing.

Activating Pairing Mode on the SRS XB21

With the speaker powered ON, you press and hold the same button until you hear a series of rising beeps, and the speaker announces in a lady’s voice, “Bluetooth pairing.”  Then release the button.  The speaker is now in pairing mode, and the Bluetooth Status lamp pictured above begins fast flashing.

You need to do this anytime you want to pair the 21 with a never-before-paired Bluetooth source device.  When in this (a.k.a. Discovery) mode, the speaker sends out its name and other connection info over the Bluetooth air channels. Then, this allows nearby BT devices to find and connect to it. Don’t release this button too quickly, lest you turn the speaker OFF, without putting it in pairing mode.

The Volume Down and Volume Up Buttons

The 21 also has volume controls. The Volume UP and Volume DOWN buttons occupy the two positions in the center of the buttons panel, between the Play-Pause and Power buttons. Plus, you can feel their minus and plus symbol shapes. E.g. Find these controls pointed out in the next picture.

Picture of the Volume buttons on the Sony SRS XB21 speaker.
The Sony SRS XB21 speaker Volume buttons.

When pressed, these lower and raise the loudness respectively, by reducing or increasing the volume setting of the connected source device.

The Power lamp blinks once for each time you press either the Volume UP or Volume DOWN buttons. That is,  except when you hit the lower or upper ends of the volume range.  Then that light fast flashes a few times.  Furthermore, no beeps or other accessibility sounds play when you adjust the volume.

Note that you can also change XB21 volume by adjusting the controls on your source BT device.

How to Raise (Turn Up) and Lower (Turn Down) Sony SRS XB21 Volume

With the speaker paired and playing, press the minus shaped Volume Down button to decrease its sound output level. Press the plus shaped Volume Up button to increase audio output.

Note that these loudness controls have no effect when the speaker is not paired. Also, the volume setting may change from paired device to paired device. I.e. each paired device remembers its own volume setting. So you might need to re set the volume when you unpair the speaker from one source device and pair it to another.

The Play-Pause / Phone / Voice Assistant Button

The Phone / Voice Assistant button has an icon of an old style telephone receiver just above it and the button itself is the familiar right facing triangle and two vertical lines shape.  We find it at the left edge of the buttons panel. See it pointed out in the next picture.

Picture of the Play-Pause / Phone / Voice Assistant button. Sony SRS XB21 Buttons Explained.
The Play-Pause / Phone / Voice Assistant button.

Answering an Incoming Call

Press and release this button quickly to answer a call when you have this unit paired with a smart phone. Rapidly press it again to hang up the call. The item you were listening to pauses when you pick up the call, although once you disconnect from the call, you may not be able to resume music playback with this button, depending on the app you were listening in.  In such cases, you have to go into the app and un-pause it on the phone itself.

Calling Up Siri

When paired with an Apple device, you may press and hold the Play / Pause / Phone / Voice Assistant button to get Siri’s attention. Note that you must first enable Siri on the source device (phone, tablet) to use Siri in order for this to work. Siri then hears you on the built-in microphone on the XB21.  So be sure to talk at the speaker, and not at your phone, when paired with the 21.

Finally, after Siri responds, the system resumes playing what you were listening to before.

Stopping and Starting the Music

This is the Play-Pause function of this button. To use it while the speaker is playing, simply press and release this button.  Play stops and the source device goes into pause mode.  To resume play, then again, press and release the Play-Pause button.

Move Back and Fourth in a Playlist

Finally, you can skip forward to the next song, or back to the previous song in a playlist with the Play-Pause button on the XB21. As the song plays, do the following…

      • To advance to the next song, quickly press and release the Play-Pause button twice.  Upon doing that, your source device advances to the next song in the current playlist.
      • To move back and play the previous song again from the beginning, quickly press and release the Play-Pause button three times.  When you do that, your source BT device jumps back one song from the current one in the current playlist, and plays that song from the beginning.

Sony SRS XB21 Buttons Explained: Back Panel Buttons


This button switches the party lamps on the front and ends of the speaker ON and OFF. E.g. See it in the next photo.  It’s at the top of the vertical row of three buttons in the port compartment.

Picture of the -BATT- button.
The -BATT- button.

How to Turn Speaker Party Lights ON and OFF

The two turquois lamps pulsate, fade, flash, and change brightness on the XB21, and are ON by default. I.e. Either when fresh out of the box, or after a factory reset.  But you can turn them off by pressing and holding for three seconds the LIGHT-BATT button.  Doing so may save a bit of battery power, especially when you don’t really need to waste any on running these lamps and need to get maximum playing time from the speaker. You might also deactivate them when playing the speaker in daylight or in a bright room where the lights would be harder to see anyway.

The dark party light bars.
The party light bars are dark.

Then to turn them back on again, simply repeat what you did before.  I.e. Press and hold in the LIGHT-BATT button for three seconds. At that point, the party lamps will resume their flashing.

How to Get Battery Percentage Remaining

Quickly press and release the same button (the LIGHT-BATT button) any time the speaker is ON. Then the unit speaks that percentage number of battery power left to you in a female voice.

The Wireless Party Chain (WPC) Button

This WPC  function lets you join from two to a hundred compatible speakers such that both play the same program. Why do this?  Because, as with the Connect Plus and Party Boost feature on JBL speakers, you get a wider coverage area when you have more than one speaker in sync, than when just one is playing. So you get more volume to spread around bigger party areas.

Picture of the WPC button..
The WPC button.

How to Set Up WPC Mode

Now to create a party group, you can use any combination of XB20, XB21, XB30, XB31, XB40, and XB41 models. Furthermore, the GTK-XB60, GTK-XB90 Sony models work here as well.  Now In WPC mode, unlike with stereo pairing, you can indeed mix and match different speaker models, so long as you do it with only the models listed here.

To form a WPC group of speakers, do as follows.

Get the Speakers Together
    1. Position all speakers you wish to add within 3.2 feet, or 1 meter, of your phone or tablet from which you’ll be playing the music.
Start WPC Mode on Speaker One
    1. Power up the first speaker.  We’ll call this one  Speaker One.
    2. Pair Speaker One with your source Bluetooth device.
    3. Press the WPC button on Speaker One for three seconds. The WPC (Wireless Party Chain) light will start blinking. E.g. See this light in the next picture below. Then after a few seconds, this lamp stops flashing, and begins glowing a solid white.
Start WPC Mode on Speaker Two
    1. Next, turn on the second speaker.  I.e. Speaker Two.
    2. As you did on Speaker One, press and hold the WPC button on Speaker Two  for three seconds.  The WPC light begins flashing on that speaker for a short time. Then it glows steadily. Also, the Bluetooth lamp on Speaker Two goes dark. At this point, you have successfully created a WPC  link between these two speakers. Note that once you initiate WPC on Speaker One, you have just one minute to complete the connection on Speaker Two.  If you do not, the waiting Speaker One times out, and returns to normal single-speaker Bluetooth operation.
    3. Finally, once you connect to the new WPC group, you can start playing music on that device. Then it will stream to that speaker group, and you’ll hear the program on both speakers.
    4. Now to add other speakers to the group, repeat steps 1 through 2 on the speaker you’re adding.

How to End WPC Mode

When you’re ready to break the WPC link, simply press and hold the WPC button on Speaker One for three seconds.  A tone then sounds and the WPC light goes out, meaning that the link is now broken.

The dark (OFF) WPC light. Sony SRS XB21 Buttons Explained.
The WPC lamp OFF (dark).

Then simply turn off the speakers that you’ll no longer be using.

The Add Button

The Add button is used to connect two Sony XB21 speakers together for stereo sound (Stereo Mode), or as two monophonic speakers for extra volume (Double Mode). To use two speakers together like this, you first create a Bluetooth connection between the speakers.  Then, you set up a Bluetooth connection between this pair, and the source Bluetooth device you’ll be playing music from.  Plugging a cord into the Audio Input port ends the Add function.

Picture of the Add button.
The Add button.

How to Use the  Add  Button

You need two Sony SRS XB21 speakers to use the Add feature for either Stereo or Double modes.

Turn the First Speaker On
    1. Start with both speakers powered OFF.
    2. Power up the first speaker, and watch for the Power / Pairing lamp to begin flashing white.
    3. Press and hold the Add button for around three seconds, until that XB21 beeps.
Turn On the Second Speaker
    1. Next, power up the second speaker.  Again, its Power / Pairing lamp should start flashing white.  Note that you have one minute to do this after putting the first speaker in Add mode.  Otherwise, that speaker times out, and reverts to a single BT speaker configuration. If this happens, power down both speakers, and start over with step 1.
    2. Press and hold the Add button on the second speaker for three seconds, until this XB21 beeps.
Pair Source Device to the New Sony Speaker Set Just Created
    1. Then, pair your Bluetooth source device to your XB21 speaker set that you just created.
    2. Begin playing something on your BT source device, and you should hear it play on both speakers.
    3. Then, adjust the volume using the controls on one or the other speaker.  Adjusting volume on one also changes it on the other.

To Switch Between Add and Double Mode

    1. To switch between Double Mode and Stereo Mode, press and release the Add button on one of the speakers. When in Double Mode, each speaker plays a mono version of the content, which contains both the left and right channels.  But in Stereo Mode, one speaker plays the left channel while the other plays the right.
    2. To end this speaker tethering, simply turn off both speakers.

Sony SRS XB21 Buttons Explained: The Reset Button

Find this recessed button on the speaker back, just to the right of the Audio In port.  To work it, insert a paper clip end and gently press.

Picture of the Reset button on the Sony SRS XB21 speaker.
The Sony SRS XB21 speaker Reset button.

Now unlike reset buttons on many other speakers, this button does NOT restore the unit to its factory default state.  Instead, you press this only when the speaker becomes unresponsive or otherwise misbehaves.  E.g. It won’t power ON or OFF, or the other buttons do nothing when you press them. Thus, pressing Reset does not clear the stored Bluetooth pairings from memory.

It does appear however, to disconnect the speaker from its battery by brute force. So pressing it causes a hard shutdown to occur. Further, releasing it applies battery power again.  You can then turn the speaker on with the Power button.

The hope with this design is that the unit will again respond to other button presses when cold started after a Reset button press.

How to Use the Reset Button

Should the 21 lock up or become non responsive to button presses, press and release this button.  If the Power lamp is ON, it should shut OFF right away. Note that the speaker does not come back on when you release this button.  So to turn it on again, press the Power button.

Sony SRS XB21 Buttons Explained: Combinations and Codes

The Reset Button Code Combination

Note that this is different from the Reset button described in the last section. This method is how to actually factory reset the XB21 to return it to factory default settings.  The Reset button described earlier does not do this however.  But it is possible to run a true factory reset on the 21, as follows.

With the speaker powered ON, press and hold the  Power  and Volume DOWN buttons at the same time until the speaker powers OFF and all the top panel lamps go out. E.g. See these buttons pointed at by the aqua arrows in the next picture.

The -Power- and -Volume DOWN- buttons. Sony SRS XB21 Buttons Explained.
The -Power- and -Volume Down- buttons.

You may wish to reset the speaker to fix any unusual behaviors you notice from it such as failing to pair, sound distortion, failure to power off when you press the  Power  button, pressing the Reset button does not solve your issue, and so on. Note that resetting invalidates any saved connection info about this speaker on your source Bluetooth devices. So you’ll have to forget those connections on these devices, and re pair the speaker after a reset in order to play your audio content through it once again.

For more details, check out our post that describes How to Reset Sony SRS XB21 Wireless Speaker.


Finally, keep in mind that you can control most of these XB21 functions from your phone or tablet, instead of using the buttons on the speaker directly.  For that, you need the Sony Music Center app.  In there, you can adjust speaker volume, turn it off, update its firmware, use a simple audio equalizer to tailor its sound to your individual tastes, and other actions.  But how to use that app is beyond the scope of this post, though if enough of you want that information, we may develop a piece that describes that later.

Other Posts About the Sony SRS XB21

    1. How to Turn Off the XB21 Bluetooth Speaker
    2. Telling if This Speaker is Charging
    3. How to Put the XB21  in Pairing Mode
    4. Pairing Details for This Bluetooth Speaker
    5. How to Make the XB21 Discoverable

Related Posts to Sony SRS XB21 Buttons Explained

    1. Sony SRS XB01 Buttons Explained
    2. Sony SRS X11 Buttons Explained
    3. All Buttons on the Sony SRS XB43 Explained
    4. Sony SRS XB13 Buttons Explained
    5. XB12 Sony SRS Buttons Explained

References for Sony SRS XB21 Buttons Explained

    1. The XB21 Sony Speaker Product Page at Sony.com

Revision History

    • 2021-09-30: First posted.