Portable model, the Bose SoundLink Flex Bluetooth speaker is equipped with a powerful broadband speaker associated with two passive radiators. Capable of adapting its sound signature according to its positioning, waterproof and resistant to falls, the SoundLink Flex seems designed for swimming pool edges as much as hiking.
The Bose SoundLink Flex speaker // Source: Tristan Jacquel for Frandroid
A Bose loudspeaker is always a small event, as the American manufacturer has marked the history of hi-fi and sound systems, with acoustic systems with an often impressive performance/size ratio. Bose, which communicates very little technical information on its speakers and prefers to highlight their sound qualities, has nonetheless filed strings of patents, relating in particular to compact acoustic loads for woofers. In other words, the manufacturer knows a lot about the reproduction of low frequencies with small Bluetooth speakers. A good reason to test the Bose SoundLink Flex portable speaker.
Bose SoundLink Flex spec sheet
| Bose SoundLink Flex | |
|---|---|
| Dimensions | 90 x 201 x 52mm |
| Weight | 600g |
| Autonomy | 12 hours |
| Connectivity | Bluetooth 4.2 (AAC and SBC) |
| Waterproofing | IP67 |
| Speakers | 1 speaker, 2 passive radiators |
This test was performed with a speaker lent by Bose.
Bose SoundLink Flex design
The Bose SoundLink Flex does not really look like other portable speakers on the market, which are often cylindrical. The Flex has an oblong shape, is designed to lay flat, with the speakers facing up, for vertical sound distribution.
The Bose SoundLink Flex speaker is designed to be positioned horizontally or vertically // Source: Tristan Jacquel for Frandroid
The base of the speaker is largely lined with anti-slip and shockproof silicone, while its upper part is covered with a powder-coated metal grille. On the back are all the control buttons (power on, play/pause/take call, volume, pairing), again covered with thick silicone. The only connector present is the USB-C charging port, housed on the left side. The speaker is equipped with eight feet molded directly into its silicone shell. Four help to stabilize it horizontally and ensure that the lower acoustic grille is not impeded. Four others facilitate the vertical positioning of the speaker.
Use and application of the Bose SoundLink Flex
From the first contact, the Bose SoundLink Flex speaker reassures: its grip is excellent and it seems difficult for it to slip out of your hand. And even so, the thickness of the silicone gives it an obvious resistance to shocks. Thanks to its dust and water resistance (IP67), the speaker can be taken absolutely anywhere. What’s more, she is not afraid of being immersed in water and floats.
The Bose SoundLink Flex speaker control buttons // Source: Tristan Jacquel for Frandroid
Powering it up is accompanied by a voice announcement indicating its battery level, then which device it is trying to connect to. The Bose SoundLink Flex can memorize more than ten and searches for them successively, while specifying which ones they are. Simultaneous connection to two Bluetooth devices is allowed.
Bose offers a companion app for the SoundLink Flex speaker. This is Bose Connect. It meets the main needs, namely the possibility of updating the firmware of the speaker, to change its name, to activate or not the voice prompts (multilingual, a good point), to activate the automatic power-off or to consult the user manual.
The Bose SoundLink Flex speaker can be paired with a second Bose speaker to increase sound coverage. Finally, the Bose Connect app allows you to manage the current music playback, without going through the streaming service app.
Impeccable Bluetooth connection
I encountered absolutely no pairing problems or stability of the Bluetooth connection with the Bose SoundLink Flex, which always works over 10 meters away outdoors.
Bose SoundLink Flex audio
The acoustic solution chosen by Bose is based on a circular broadband loudspeaker, loaded by two oblong passive loudspeakers. The active driver with a diameter of approximately 5 cm is housed in the upper right part of the enclosure, while the upper and lower passive radiators are housed in the left part.
A passive load for a fuller bass
The principle of passive charging is frequently used with mobile speakers, because it allows low frequencies to be reproduced with a larger volume, without increasing the charging volume and therefore the dimensions of the speaker.
The second passive radiator is housed at the bottom of the enclosure and diffuses the low frequencies through a second grille // Source: Tristan Jacquel for Frandroid
For this to work, the active speaker and the passive speakers share the same internal air volume. When the active produces a bass sound, the passive radiators start to vibrate. The sound they produce is then added to that of the active loudspeaker and this is the main interest of this acoustic assembly. The downside of the passive load — negligible with a non-hi-fi speaker — is the inertia induced by passive radiators, which reproduce sound with a slight delay. It’s inevitable: the sound is first produced by the active loudspeaker, then amplified through the passive membranes.
The Bose SoundLink Flex speaker is easy to take with you // Source: Tristan Jacquel for Frandroid
This defect can be partially compensated by the use of an active loudspeaker equipped with a powerful motor, thus able to pass more quickly from one frequency to another. This is the case of the Bose Soundlink Flex speaker, whose main speaker is flanked by a large magnet.
Signature sound
The Bose Soundlink Flex speaker adjusts its sound signature according to its positioning, thanks to an on-board sensor (PositionIQ technology). Thus, when the loudspeaker is laid flat, the high-mid and treble frequency registers are considerably boosted, in order to compensate for the off-axis positioning of the listener and the inherent attenuation of the high frequencies. On the other hand, when the loudspeaker is positioned vertically or suspended — that is, the main loudspeaker is directed towards the listener — this tonal correction is deactivated.
Used at the beach, the Bose SoundLink Flex remains perfectly intelligible // Source: Tristan Jacquel for Frandroid
If the intention is commendable, the automatic correction PositionIQ goes a little too much and thus highlights the limits of this broadband speaker, which is not as precise and fast in the treble as a tweeter. At high volume, the treble thus lacks fluidity. It’s annoying indoors, much less in a noisy environment, for example at the beach, where the speaker remains intelligible despite the surf. Moreover, it is not excluded that Bose has set up this equalization precisely so that the speaker is audible placed on the ground outside.
In a low-noise environment, the Bose SoundLink Flex is more pleasant to listen to in a vertical position, as here // Source: Tristan Jacquel for Frandroid
Let’s go back to the sound signature of the Bose Soundlink Flex, positioned vertically or suspended, therefore without tonal correction. And there, it’s very good, with a convincing bass, generous in volume, nervous in the upper part of the register, and which does not hesitate to go down to around 60 Hz, thus offering a surprising extension for such a small pregnant. The midrange is soft and precise, the treble in front, with a peak of presence beyond 10 kHz, but which brings just a touch of pleasant brilliance.
Dynamic behavior
The small speaker of the Bose Soundlink Flex is solidly motorized, you can hear it as you push the volume, because it does not disunite and its reproduction retains a certain balance. Ditto for the amplification, which does not crack when pushed to its limits.
When suspended, the Bose SoundLink Flex retains its original, more balanced sound signature // Source: Tristan Jacquel for Frandroid
Moreover, Bose has set up a dynamic equalization: beyond 60% of the volume, the low frequencies are gradually reduced so as not to exceed the excursion capacities of the loudspeaker. This small speaker can therefore be listened to fully, although it is less pleasant than at half power. In any case, all this is seriously thought out.
Bose SoundLink Flex microphone
Making audio calls with the Bose Soundlink Flex is possible, but performance from the onboard microphone is average. It doesn’t filter surrounding noise well, and digital post-processing adds metallic undertones to the user’s voice. On the other hand, you can hear your interlocutor perfectly.
Battery life of the Bose SoundLink Flex
The Bose speaker is equipped with a battery of approximately 3000 mAh, capable, according to the manufacturer, of offering an autonomy of 12 hours. In practice, when used at 50% of the volume, the loudspeaker gives up shortly before this time (11:30).
The USB-C charging port of the Bose SoundLink Flex speaker // Source: Tristan Jacquel for Frandroid
The Bose SoundLink Flex takes about 4 hours to charge, which is slow, but should preserve battery life.
Bose SoundLink Flex price and availability
The Bose SoundLink Flex speaker is available at a price of 169 euros, in the colors black, cloud white and slate blue.