Bose SoundLink Flex is designed to withstand harsh weather, and if you lose it in the spa or pool for a few minutes, it’s fine. The same goes for shallow water at the beach, as it’s also dustproof and can therefore withstand salt and sand.
It has a nice, rounded shape, and while it’s not exactly pocket-sized, it’s slim enough not to bulge out of a bag or small backpack.
In other words, we’re talking about a competitor to favourites like the Sony SRS-XB33, JBL Charge 5 and Sonos Roam.
As a weapon against its nearest competitors, the Bose SoundLink Flex also has a built-in microphone for mobile calls, so you can sit on the beach listening to music and then answer incoming calls without having to get out your connected mobile phone. None of the aforementioned rivals can do that.
By contrast, the Bose speaker only has Bluetooth version 4.2, which basically rules out so-called multi-point connectivity, meaning it can be connected to two sources at the same time. For example, PC and mobile phone. But Bose has somehow managed to include this, and you can switch between the two by pressing the Bluetooth button twice.
It doesn’t work smoothly though, and with my iPhone and MacBook Pro connected I experienced dropouts, while it was very inconsistent how it switched between the two devices. Bluetooth 5 would definitely have helped here.
Battery life and range
Otherwise, a battery life of up to 12 hours is okay, as is a charging time of around four hours via USB-C. The wireless range is given as 9 metres, but at the same time the manufacturer’s website says you can connect a device from up to 30 metres away.
Ergo, I had to step up myself. Inside our office building, I was able to take the speaker through open doors and hallways about 20 feet away from the cell phone before the audio stream became unstable.
Outdoors, however, I could take the speaker 40-50 feet away from the phone before the dropouts began. That’s really good, especially considering that Bluetooth 4.2 usually has significantly shorter range than version 5.
Ease of use
The Bose SoundLink Flex has buttons under the rubber on top, where you can adjust the volume on separate buttons or pause and start the music with a press of the middle button. The same is done to answer or end a call. Press twice to skip a song and three times to return to the previous one. Or press and hold to activate the phone’s voice assistant.
The Bose Connect app lets you pair multiple compatible SoundLink speakers in so-called Party Mode, and if you have two SoundLink Flexes, they can be paired in stereo.
When you get a call, it’s easy to answer, and the sound was just fine during a couple of conversations I had during testing. No problems there.
The sound of Bose SoundLink Flex
Bose usually stands for a round and pleasant sound, but often a bit flat dynamics with coloured bass and restrained midrange. Here SoundLink Flex surprises positively. In a way. Because when the speaker is angled directly towards the ears, the sound of both music and news is crystal clear, the bass is pleasantly full without being overdone, and the treble clear and distinct.
Music sounds much more natural than I expected, and the speaker has many of the same strengths as the Sonos Roam – and can play louder, too. It has about the same sound pressure level as the JBL Charge 5 and a bit more than the Sony XB33. In other words, it plays more than loud enough for the purpose, without winning any awards as Party Speaker of the Year.
Poorer sound from the side and from above
The sound, however, changes quite drastically as soon as you move away from the speaker’s axis. The dispersion characteristic is rather narrow and the bass suddenly becomes quite swollen compared to the midrange if the speaker is placed at a height other than at ear level or it is angled to the side. More than I’m used to from other speakers in the same category, including the competitors mentioned.
This makes guitars and singing voices – especially female ones – sound rather coloured, for example, and suddenly the voices of newsreaders don’t come through as well. Whatever the angle, the dynamics are also a little tame, especially when you turn it up.
Personally, I rarely place a portable speaker like the SoundLink Flex at a perfect angle to my ears, so music ends up sounding just a tad bloated and coloured. On the other hand, it never gets sharp and uncomfortable, Bose should have that gift.
By comparison, the aforementioned JBL Charge 5 is a notch more pointed in the treble. And the Sony XB33 needs a trip past the equalizer to get the treble out well enough.
Which leads me to a wish, namely that Bose includes an equalizer for SoundLink Flex in a forthcoming update of the Connect app. Currently, there’s no option to tweak the sound as you like, which you can on both Sony and JBL.
In Bose’s favor, there’s a built-in gyro sensor – Bose PositionIQ – that detects how the speaker is positioned (horizontally, vertically, etc.) and optimizes the sound accordingly. Nice enough, but it’s no substitute for manual EQ, nor is the Bose speaker as precise as the Sonos Roam at adapting the sound to the environment it’s playing in.
The Bose SoundLink Flex is a practical portable speaker that can withstand water and is also completely dustproof. Ease of use is good, as it often is on speakers of this kind. The fact that you can use the speaker for mobile calls is also a plus.
The sound quality is good and well balanced when you are at a direct angle to the speaker. It can also play more than loud enough for an evening of wine on the rooftop or other situations that don’t include dancing or headbanging. But it has a little tame dynamics, and we’d like to see female voices come through better.
If the speaker isn’t angled directly towards your ears, much of the clarity disappears and the bass becomes overly swelling. This compromises the ease of placement, which we think is important in the portable class.
It’s a caveat we have to take into account in our recommendation of the SoundLink Flex.