Bose's second rogue model, the SoundLink Flex aims to deliver a quality sound experience in a portable, rugged, clever and easy-to-use format. A promise largely kept.
The Flex joined the very large family of Bose SoundLink portable speakers in December 2021. Available in three colors, this model is positioned in the manufacturer's catalog as a resolutely adventurous, robust and waterproof (IP67 certification) product, which can be identified as a larger evolution of the excellent SoundLink Micro.
Bose claims above all the great ease of use of its new portable Bluetooth speaker thanks to numerous integrated controls/voice prompts and some practical features (pairing with other speakers to extend music distribution, mobile companion app, hands-free kit, multipoint). Sound reproduction has obviously not been put aside, on the contrary, since we are promised "a clean, clear, undistorted, balanced sound [with] powerful bass". The full-range driver and the two integrated passive radiators will allow you to "hear every instrument and every nuance". The PositionIQ technology would be in charge of automatically adapting the restitution of the speaker according to the way it is positioned.
The SoundLink Flex comes in the form of a beautiful 587 g block measuring about 9 x 20 x 5 cm and with very rounded edges. The speaker fits easily in the hand, thanks in part to its silicone coating, and fits comfortably in a front pocket of a backpack (but by no means in a conventional pants pocket). There's not much to complain about in terms of build quality and finish: the SoundLink is sturdy and can withstand small accidental drops, as well as being used near water, at the beach or even in water since it's waterproof (IP67 certification). In the case of contact with water, it will obviously be necessary to take care to dry the speaker, in particular at the level of its USB-C connector, before charging it.
On this model, Bose has tried a new way to hang its portable speaker, this time by a simple strap - not indicated as detachable, but "tearproof" - present on the left edge. A simple and always practical system, but a carabiner among the supplied accessories would not have been too much...
The SoundLink Flex follows the trend that has been going on in the portable speaker market for a few years now, and therefore has no wired audio connection. Unfortunately, there is no question of using it directly via USB as is the case with the SoundLink Revolve.
So we have to make do with the only Bluetooth wireless connection (4.2, SBC codec only supported), but which has the advantage of offering a multipoint pairing function for two devices simultaneously, which is still rare on a portable Bluetooth speaker.
Controls & application
The SoundLink Flex isn't one of those speakers that provides a myriad of features, but that doesn't stop it from being extremely pleasant to use on a daily basis. The Bose portable speaker is easy to use, even without the help of the companion Bose Connect app. The SoundLink Flex has plenty of built-in voice alerts and a few light indicators. All the necessary buttons and controls are directly accessible to manage playback, pairing, calls, volume, navigate between tracks, pair with another speaker, easily switch to another source, or find out the remaining battery level. A delight.
Although sober, the Bose Connect app (iOS, Android) offers a few little extras. The user can indeed benefit from a tutorial and some nice little customization options, such as the configuration of the language of the voice aids (and even their pure and simple deactivation if necessary), a slightly easier management of the connected/memory devices and the pairing with another speaker, or the activation and configuration of an auto sleep mode. However, there is no option to customize the sound of the speaker.
Like a few other competing models, the SoundLink Flex can be paired with another Bose SoundLink in stereo and with multiple speakers in Party Mode to play the same content. Unfortunately, we didn't have any other models available to see how well this option worked.
The autonomy promised by the SoundLink Flex amounts to a solid 12 hours, a value that we only managed to reach at a moderate volume, sufficient for close listening in a small room such as a bedroom. If you push the speaker a little more for a larger room or outdoors, the average usage time is more like 11 hours. This is still a respectable score, far from the exceptional 20-hour autonomy of the Marshall Emberton, for example, but in the high average of portable speakers.
On the other hand, you'll have to be patient to recharge the battery, as it takes between 3 and 4 hours to fill up.
Who would have thought it in 2022! Unlike the vast majority of its competitors, the SoundLink Flex includes a microphone to act as a hands-free kit. This one offers a more than honorable performance as long as you are in direct proximity of the speaker (less than 1 m, or even 50 cm outdoors).
The signal is not extremely precise, but it is clean (low background noise), powerful, rich and homogeneous enough to allow a convincing capture of the voice - the timbre of the latter being moreover rather well preserved.
The communication latency in Bluetooth is about 175 ms. This is a relatively high value in absolute terms, which, when translated into a sound/picture lag, frankly limits the comfort of watching a video. The SoundLink Flex is nevertheless capable of automatically compensating for this delay with most smartphone video-playing apps (Netflix, Disney+, YouTube, etc.), thus allowing viewing in good conditions.
Bose is full of praise for the sound performance of its speaker, and it is true that this model can impress in some aspects. But not everything is so perfect...
There's an undeniable continuity to the sound signature of Bose portable speakers, and the SoundLink Flex proves it once again. The portable speaker of the American manufacturer adopts indeed the formula that we know well to him: a flattering and energetic sound, brought by bass and highs in front, combined with a generous extension on both sides of the spectrum (notably in the lowest frequencies), the whole remaining homogeneous, coherent and quite respectful of the timbres. A very large part of this coherence is due to the extremely well balanced, not to say linear, restitution of which the loudspeaker shows between the low-midrange and the beginning of the highs. It is difficult to take it back on this point.
As we found with the SoundLink Micro and its famous distant cousin, the SoundLink Mini II, the SoundLink Flex surprises us with the depth of bass it delivers. Although larger than the latter, the SoundLink Flex's bass extension is still impressive given its volume, allowing the speaker to deliver a rich, round, immersive bass with good footing and a convincing sense of impact.
Although the warm sound that comes out of the extreme bass is particularly pleasant, especially for outdoor use, the two passive radiators of the Bose portable loudspeaker are a little too generous, which leads to frequent overflow and masking effects on the low-mids. In other words, it regularly happens that the bass "drools" and takes a little too much space. The effect is very easily identifiable as soon as the instruments multiply (bass drum, bass tom, double bass/bass, cello, low notes on the piano or synth layers...) or on very close bass drum hits. The basses become "compact" and we have a lot of difficulties to identify each protagonist.
The SoundLink Flex is also very resourceful when it comes to reproducing the other end of the spectrum, the treble/extreme highs. The treatment reserved for this zone is also particularly flattering here and has the effect of artificially boosting fine details, room effects (e.g. reverberation) and the brightness of the treble. We recognize that the result is rather pleasant and allows to perceive certain subtleties of its music... Nevertheless, the reproduction of the highs lacks finesse and detail, and that is felt especially when one wishes to push the loudspeaker to a more generous volume, to listen to its music in outside for example. In this case, the highs become a little aggressive and the sibilance is more and more present.
The increase in volume is also accompanied by a certain crushing of the dynamics, until then nicely preserved, then by a collapse of the bass and rather unsightly "pumping" effects in the most extreme sound levels. To preserve the pleasure of listening, it is better to remain under the bar of 70-80% of the maximum volume, which is enough for a listening of proximity to a few meters of the loudspeaker in outside or to diffuse its music in a living room.
Finally, it should be noted that the SoundLink Flex does not promise a homogeneous 360° reproduction, nor even stereophonic: it is a perfectly monophonic portable speaker with a particularly marked directivity. The midrange and high frequencies lose their presence as soon as the speaker is not directly in front of it, which is especially true when it is in a standing or hanging position. In the lying position (Bose logo pointing upwards), the speaker still delivers a homogeneous reproduction for the users positioned around it and, with the help of an integrated sensor, automatically activates a signal processing that allows to keep a certain homogeneity in the highs.
The SoundLink Flex is an accomplished, rugged portable speaker that delivers on its promise of ease of use and robustness. Its sound performance isn't perfect, especially when pushed to loud volumes, but it's still a solid performer. This model will satisfy music lovers looking for a simple, efficient and solid listening companion.