JBL Flip 4 vs Sony SRS-XB21 - Which one is the better outdoor speaker?

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The JBL Flip 4 and the Sony SRS-XB21 are two big rivals in the compact, outdoor speaker category.

Both are durable, waterproof devices in the same price range, so I thought it would be interesting to do a detailed comparison to find out which one is the better choice.

In the last days, I tested several different attributes of the speakers to find this out and summarized my results in this JBL Flip 4 vs Sony SRS-XB21 ultimate comparison review.

So let’s see which one is the winner.

Bluetooth range

Battery life

Water protection



Bottom line



Flip 4

Bluetooth range:

  • 200 feet

Battery life:

  • 70% volume: 6 hours 40 minutes
  • Maximum volume: 3 hours 10 minutes

Water protection:

  • IPX7
  • Completely waterproof, it can be submerged into 1-meter-deep water for 30 minutes


  • Long Bluetooth range
  • Durable design
  • Water protection
  • Nice, balanced sound


  • No track navigation buttons

Bottom line:

The Flip 4 is a great, durable outdoor speaker. It has longer Bluetooth range, battery life, and a better overall sound, so in most cases it is a better choice than the XB21.




Bluetooth range:

  • 90 feet

Battery life:

  • 70% volume: 2 hours 40 minutes and another 2 hours 20 minutes at 50% volume
  • Maximum volume: 2 hours

Water protection:

  • IP67
  • Completely waterproof, it can be submerged into 1-meter-deep water for 30 minutes
  • Dustproof


  • Durable, solid device
  • Waterproof and dustproof
  • NFC
  • Light effect, party booster mode


  • Short battery life
  • No track navigation buttons
  • A bit tiny sound with weak mids

Bottom line:

While the XB21 has some extra, unique features and overall, it is a great compact speaker, in many important attributes it lacks behind the Flip 4. 


What makes this comparison even more interesting that the price of the two speakers are really similar.

Click here to check the current price of the JBL Flip 4

Click here to check the current price of the Sony SRS-XB21

Both speakers come in a paper box with only a micro USB cable included.

In terms of colors, you can choose from six different colors by the Flip 4 and from four colors by the XB21.

The Design

The design of the speakers is very similar, both have a cylindrical shape and a durable fabric enclosure.

Even their dimensions are almost identical, the Sony is a bit longer.

In terms of build quality, both speakers feel solid and well-built, they can survive some accidental drops as well.


Definitely, the most signature design element of the Flip 4 is the exposed bass radiators at the ends of the speaker.

They look pretty cool when they are moving to the beats of the songs, you can literally see the music not just hear it.

This is also true for the XB21 although it does not have visible bass radiators, it features two LED lights built-into the front panel of the speaker creating a nice light effect while playing music.


The Flip 4 got a large plastic line at the back which stops it from rolling over on flat surfaces.

For the same purpose, the XB21 got four small rubber legs.

Here, I think the JBL’s solution is better, it provides a more stable base for the speaker, the legs of the XB21 work well on hard surfaces, however, it can easily lose its balance on softer surfaces for example if you are using it on a bed.


Music Control

The Flip 4 houses four control buttons on the top, which are large embossed signs over the speaker grille.

The buttons are great, they are large and clicky enough.

The XB21 also has four rubber control buttons, however, they are much smaller and not so convenient to use.

In terms of music control, none of the speakers has dedicated music navigation buttons.

The Flip 4 has a limited music control capability, which means you can pause/play the music and jump to the next song, however, it is not possible to go back to the previously played song or to forward/backward in a song.

The XB21 is a bit more powerful, with it you can also jump back to the previously played song.

Both speakers have a built-in microphone, so they can be used as a speakerphone to answer phone calls.


Attachment Option

To increase its portability, the Flip 4 got a shoelace type lanyard, which can be used to hang the speaker on a hook or on the handlebar of your bike.

In addition, it gives an extra security wearing it on your wrist when you are carrying the speaker around.

Unfortunately, the Sony XB21 did not get any attachment option, it does not have even a loop or cutout where you could attach a lanyard or carabiner to it.

If you are lucky, it will fit into a drink holder slot of your bag but otherwise, you do not have any option to attach it to your bike or backpack.

Water Protection

The JBL Flip 4 got an IPX7 water protection, which means it is completely waterproof, it can be submerged into 1-meter-deep water for 30 minutes.

The Sony XB21 got an IPX67 protection, which means it is not just completely waterproof but it is also protected from dust, so you don’t have to worry if you use it on the beach.

Sony even claims that it is shockproof and it has been drop tested from up to 4 feet as well, so you don’t have to worry if you accidentally drop it.

Unlike the Flip 4, the XB21 even floats on the water, so it is a better choice for water sports like canoeing, SUP or jet ski.


To ensure the water protection, the ports are situated under a waterproof flap by both speakers.

The design of the flap is great by both speakers, they are easy to open and close and they seal correctly.

How to Setup

Setting up the speakers were easy, I did not have any problem during the pairing and connecting process.

However, here I would give the edge to the XB21 since it has a built-in NFC chip, so you can easily pair and connect your NFC enabled devices to it.


Connectivity, Bluetooth range

In terms of Bluetooth range, the Flip 4 turned out to be the winner.

In my outdoor test, I measured 90 feet Bluetooth range by the Sony XB21 and an impressive 200 feet Bluetooth range by the Flip 4.

So the Flip 4 has a twice longer range, however, it is worth to mention that even the 90 feet range is pretty good, likely you will not have any connectivity problem also with the XB21.

Both speakers feature an audio jack input port so besides Bluetooth they can be connected via cable.

Battery Life

Regarding the battery life, I did two battery tests with the speakers.

At the first test, I played different types of songs on them at 70% volume then I repeated the same test at maximum volume.

At 70% volume, I measured 6 hours 40 minutes play time by the Flip 4.

By the XB21 this measurement was not so straightforward since the speaker limits the maximum volume level to 50% if the battery level is getting low.

Unfortunately, in this case, it does not even allow to raise back the volume level above 50%.

In my test, I measured 2 hours 40 minutes play time till the XB21 set back the volume level to 50% and after that, it could operate for another 2 hours 20 minutes on the limited volume level.

So overall it played for around 5 hours before it turned off.

At maximum volume level, the Flip 4 provided 3 hours 10 minutes play time, while the XB21 could play music for 2 hours, after that, it started to limit the volume level.

So the Flip 4 was the winner here, the battery life of the XB21 is pretty short, it is below the average.

Another bummer of the XB21 is that its battery level indicator is not precise.

It happened many times that it indicated that the battery level is around 50% and just after some minutes the speaker started to limit the maximum volume level and the voice prompt asked to charge the device.


Extra Features

It is worth to mention that the Sony XB21 has a unique feature which is the Party Booster mode.

It means that tapping the speaker from five different directions will cause it to play various sounds, so it can be used as an instrument.

The type and the volume of the sound effect change depending on which surface you tap and how strongly you tap it.

While it is fun at first, on a long term I don’t think many people will use it, since it is not precise enough to be used as a real drum pad, so don’t expect that you will be able to play any complex beat or rhythm with it.

Sound Test

Under the hood, the Sony XB21 has two 1.65” drivers and a passive radiator, while the Flip 4 has two 1.56” drivers and dual passive radiators.

Regarding sound quality, both speakers have a pretty clear sound, which is distortion free even at higher volume levels.

Their highs are nice and crisp and they have a pretty decent bass production, they can even hit some deeper notes.

However, the sound of the XB21 is a bit thin compared to the Flip 4.

In its sound mainly the highs dominate while the mids are not so powerful, the Flip 4 has a fuller, bigger sound.

So regarding sound quality, the Flip 4 is the winner, it has a better overall sound.

JBL Flip 4 vs Sony SRS-XB21 Sound Test Video


Overall, both speakers are great, well-built, compact device.

With their water protection and durable body, they are ideal outdoor and beach speakers.

The XB21 is the newer speaker and it provides some extra functionalities like NFC, light effect and the Party Booster mode.

However, testing their basic attributes, the Flip 4 turned out to be the better speaker.

It has a longer Bluetooth range, battery life, and a better overall sound.

So, if you are hesitating about which one to buy, I suggest choosing the JBL Flip 4.

Click here to check the current price or to buy the JBL Flip 4

Click here to check the current price or to buy the Sony SRS-XB21

If you want to know more about the speakers click here for the full reviews:

Sony SRS-XB21 full review

JBL Flip 4 full review


If you want a compact, portable speaker and can spend some more bucks then the Bose SoundLink Revolve could be a good alternative of the speakers.

It has a similar size, a durable aluminum enclosure and a nice omnidirectional sound, however, it comes with a much higher price tag.

If you are on a budget then the Anker SoundCore 2 is a great, cheap alternative.

It is a durable outdoor speaker with a long battery life and a pretty decent sound.

It is only splash-proof and it does not have so deep lows but it is available for a very reasonable price.

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Recommended products


Anker SoundCore 2

at Amazon


JBL Flip 4 

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Bose SoundLink Micro

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JBL Charge 3

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