The Bose SoundLink Flex is a small portable Bluetooth speaker that can accompany you everywhere from house parties to picnics. Its IP67 rating certifies it to be fully dust-tight and immersible in up to a meter of water for 30 minutes, meaning you can bring it outdoors without issue. Wherever you go, its PositionIQ technology adjusts the speaker's audio reproduction to meet the unique acoustics of your space.
Our Verdict
The Bose SoundLink Flex is acceptable for music listening. Out of the box, this small speaker reproduces voices and lead instruments with detail and clarity, so it's suitable for most genres. EDM fans might mourn the loss of low-end thump, but that's the compromise you make for speakers this size. It gets loud enough to fill an average-sized room with sound, but it won't be the best choice for blasting the hits outdoors at your summer BBQ. Its app lets you pair it with other Bose speakers but lacks customization tools, so you can't customize its sound to suit your preferences.
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Good performance with dialogue.
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Requires two units for stereo audio.
The Bose SoundLink Flex is middling for videos and movies, but it's not really designed for this purpose. While it can reproduce dialogue with clarity, on its own, it can't reproduce cinematic low-end rumble or immersive stereo soundscapes, and if you turn it up to try and compensate for this, your audio will get compressed. It also has some latency issues, especially when paired with iOS devices, so you might encounter lip-sync issues. That said, different apps and devices compensate for latency differently.
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Good performance with dialogue.
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No graphic EQ or presets.
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Compression at max volume.
The Bose SoundLink Flex is good for podcasts. Its mid-range is virtually flat, so dialogue is rendered accurately and with plenty of detail. With its portable design, you can easily take your shows with you from room to room. It's loud enough to fill an average-sized room, but not quite loud enough to fill more open spaces like basements.
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Outstandingly portable.
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Can be paired to two devices at once.
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Good performance with dialogue.
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No graphic EQ or presets.
The Bose SoundLink Flex doesn't have built-in voice assistant support, but if you have a smartphone with Google Assistant or Siri, you can pair it to the speaker to control it with your voice. It does a passable job at this. Amid a noisy party, it doesn't have any trouble hearing your commands, and it can also pick them up from further away.
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Excellent far-field performance.
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Voice assistants aren't built-in.
This speaker is decent for the outdoors. It's easy to bring along with you thanks to its small and lightweight design. It's rated IP67 for dust and water resistance, so it'll withstand a day at a dusty park or a drop in a puddle. With a battery life of over seven hours, it'll get you through most days on the go. That said, its directivity isn't the best and doesn't get as loud as other speakers we've tested, so it won't fill your whole backyard with sound. If you do try to push up its volume, your audio will get compressed, too.
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IP67 rating for dust and water resistance.
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Outstandingly portable.
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No graphic EQ or presets.
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Compression at max volume.
- 6.3 Music
- 5.7 Videos/Movies
- 7.5 Podcasts
- 6.2 Voice Assistant
- 7.0 Outdoors
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Updated Oct 31, 2024:
We referenced the Bose SoundLink Flex (2nd Gen) in the App box.
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Updated Oct 24, 2024:
We updated this article to align with our current standards and edited the text for clarity.
- Updated Sep 27, 2024: This review has been updated to mention the Ultimate Ears BOOM 4 in the Battery and Frequency Response Accuracy sections.
- Updated Aug 15, 2024: We've added a comparison between this speaker and the Beats Pill in Wired.
- Updated Mar 08, 2024: We've updated the 'Differences Between Variants' section to include two additional color variants: Cypress Green and Chilled Lilac.
- Updated Feb 02, 2024: We've added a comparison between this speaker and the Bose SoundLink Mini II Special Edition in Wired.
- Updated Dec 01, 2023: Added market comparison with the Anker Soundcore Motion 300 in the App box.
- Updated Nov 07, 2023: Minor text edits for clarity.
- Updated Aug 21, 2023: Updated the Portability picture for greater clarity and consistency between reviews.
- Updated Nov 14, 2022: Rewrote text for greater clarity. No changes in test results.
- Updated Jul 29, 2022: Added 'Carmine Red' color variant to 'Differences Between Sizes And Variants' box.
- Updated Nov 18, 2021: Review published.
- Updated Nov 15, 2021: Early access published.
- Updated Nov 04, 2021: Our testers have started testing this product.
- Updated Oct 29, 2021: The product has arrived in our lab, and our testers will start evaluating it soon.
- Updated Oct 21, 2021: We've purchased the product and are waiting for it to arrive in our lab.
Differences Between Sizes And Variants
The Bose SoundLink Flex comes in six color variants: Black, White Smoke, Stone Blue, Cypress Green, Chilled Lilac, and Carmine Red. This review represents the test results for the 'Black' variant; this is our version's label. We expect our results to be consistent across the various variants.
You can also find a version of this speaker called the Bose SoundLink Flex SE, which comes without a microphone.
If you encounter any other variants of this speaker, please let us know in the comments, and we'll update our review accordingly.
Compared To Other Speakers
The Bose Soundlink Flex is a small, portable speaker akin to the Bose SoundLink Micro and the Anker Soundcore 3. It's better built than both of those, thanks to its solid and sturdy materials. Like other SoundLink speakers we've tested, the Flex supports voice assistants through your smartphone, and it does an excellent job of understanding your commands from far and in noisier settings. That said, the SoundLink Flex downmixes your audio to mono, so if you prefer a more immersive sound, the 360-design of the Ultimate Ears BOOM 4 is a good alternative.
The sequel to this speaker is the Bose SoundLink Flex (2nd Gen), which adds a 'Shortcut' button to put the speaker in stereo pairing mode and support for a 3-band EQ in the companion app.
Check out our recommendations for the best Bluetooth speakers, the best waterproof speakers, and the best speakers under $100.
The Bose SoundLink Flex and the Beats Pill are similarly sized speakers with detachable carrying straps. In terms of performance features, there's not a whole lot to differentiate the two. They're neck and neck when it comes to volume, battery life, and portability, and even their default sound profiles are very similar. That said, the Beats has the ability to play audio via a wired source through the USB-C port and can even play back high-resolution content from a compatible streaming service. The Bose supports Bluetooth multi-device pairing though, so choosing between them may come down to which connectivity options you prefer.
The Bose SoundLink Flex is more versatile than the JBL Flip 6. The Bose supports voice assistants through your smartphone and is excellent at hearing your commands from afar and in noisier settings. It can also produce a deeper bass than the JBL and has a slightly longer-lasting battery life, though this varies depending on your usage habits. That said, the JBL's companion app comes with a graphic EQ to tweak its sound to your liking and offers a slightly wider-sounding soundstage.
The JBL Charge 5 and the Bose SoundLink Flex perform similarly. They both offer neutral sound profiles and are well-built with IP67 ratings for dust and water resistance. The JBL's battery lasts longer than the Bose, though this can vary depending on your usage. However, the Bose is a bit smaller in size and supports voice assistants through your smartphone.
The Bose SoundLink Flex and the Sonos Roam 2 are both portable speakers that will appeal to different customers. Both speakers downmix your audio to mono, but the Sonos has much better directivity, so the sound is fairly similar regardless of where you are in relation to it. On the other hand, the Bose produces a bit more bass by default, although you can EQ the Sonos via its companion app, unlike the Bose. But mainly, the Sonos will appeal to people who are already invested in the Sonos ecosystem, especially because the Roam 2 supports the Sonos voice assistant. On the other hand, if you'd prefer to use your device's Siri or Google Assistant, the Bose is the pick for you.
The Marshall Emberton II is better than the Bose SoundLink Flex, though they have different strengths. The Marshall can play stereo content without downmixing it to mono, resulting in a more immersive soundstage. Its soundstage is perceived as wider and more spacious. It also comes with EQ presets to tweak its sound to your liking and has longer-lasting battery life. That said, the Bose has less compression present at max volume, resulting in cleaner-sounding audio at louder volume levels. It also supports voice assistants through your smartphone and is excellent at hearing you from far away and in noisy environments.
Depending on your listening habits, you may prefer either the Sonos Roam/Roam SL or the Bose SoundLink Flex. The Sonos is Wi-Fi enabled, and its Roam variant offers fantastic voice assistant support with Alexa and Google Assistant built-in. It's smaller and more portable, too, with bass and treble adjustments to tweak its sound to your liking. That said, the Bose can get a bit louder with less compression at max volume. The Bose also has a better-balanced sound profile out of the box and has a longer-lasting battery life, though this can depend on your usage.
The Bose SoundLink Flex and the Anker Soundcore Motion 300 are portable Bluetooth speakers with similar designs. Depending on your listening habits, you may prefer one over the other. The Bose can reproduce more bass, which is great for genres like EDM and hip-hop. However, unlike the Anker, it has to downmix stereo content into mono to play it back. The Anker gets louder, too, with a longer-lasting battery life. Plus, its companion app has more customization tools, like a graphic EQ.
The Bose SoundLink Flex is better than the JBL Flip 5 overall. The Bose offers a better-balanced sound profile that can produce a deeper bass than the JBL. It's better built and can get a bit louder with less compression at max volume. It also supports voice assistants through your paired smartphone and is excellent at understanding your commands from far away and in noisy settings. That said, the JBL is just a little bit smaller, and it has better directivity, so its soundstage is perceived as a bit wider than that of the Bose.
The Bose SoundLink Flex is a bit more versatile than the Marshall Emberton overall. The Bose is better built with an IP67 rating for dust and water resistance. It can also get louder with less compression at max volume and has a more balanced sound profile than the Marshall. The Bose also supports voice assistants through your smartphone. However, the Marshall can play stereo content without downmixing it to mono and offers better directivity, resulting in a wider and more immersive-feeling soundstage. Its battery also lasts a bit longer, though this can vary depending on your usage.
Depending on your listening habits, you may prefer either the Bose SoundLink Flex or the Marshall Willen as these portable Bluetooth speakers have different strengths. The Bose supports voice assistants from your smartphone, unlike the Marshall, and it reproduces a deeper bass which fans of EDM may appreciate. The Marshall is more customizable, with EQ presets to help you control its sound, though it can't get a similar bass response to the Bose.
The Bose SoundLink Flex is a better speaker than the Bose SoundLink Mini II Special Edition. Both speakers are highly portable and have similarly balanced sound profiles that lack low-bass but feature detailed and accurate mids. They even have very similar continuous battery life performances. However, the SoundLink Flex has a better build quality and is rated IP67 for submersion in water. It also has companion app compatibility, which lets you pair it up with other Bose speakers.
The Ultimate Ears MEGABOOM 3 is a better speaker than the Bose SoundLink Flex, though they have different strengths. The Ultimate Ears offers a wider and more immersive soundstage. Its companion app comes with a graphic EQ and presets to customize its sound to your liking, and it has a longer-lasting battery life, so it's better suited to long listening sessions. However, the Bose is smaller, making it more portable, and it supports voice assistants through your smartphone. It also offers a more balanced sound profile out of the box and can produce a deeper bass.
The Bose SoundLink Flex is a better speaker than the Bose SoundLink Micro overall. The Flex has a great build quality and can get louder than the Micro. It also offers a better-balanced sound profile that can produce a deeper bass. That said, the Micro is smaller and lighter, making it more portable. It also has lower Bluetooth latency with iOS and Android devices, though some apps compensate for latency differently, and your experience may differ.
You may prefer either the Bose SoundLink Revolve or the Bose SoundLink Flex, depending on your listening habits. The Revolve's 360-degree design ensures its soundstage is perceived as wide and spacious. It also has a longer-lasting battery life, though this can vary depending on your usage. That said, the Flex has a better-balanced sound profile out of the box. It's better built with an IP67 rating for dust and water resistance. It can also get a bit louder with a bit less compression present at max volume,
The Ultimate Ears BOOM 3 is slightly better than the Bose SoundLink Flex, though have different strengths. The Ultimate Ears can play stereo content without downmixing it to mono, and its soundstage is perceived as wider and more open thanks to its 360-degree design. You can customize its sound with the graphic EQ in its companion app, and it has a longer-lasting battery life of over 13 hours from a single charge, though this can depend on your usage habits. That said, the Bose offers a better-balanced sound profile that can produce a deeper bass out-of-the-box. It also supports voice assistants through your smartphone.
The Anker Soundcore Motion+ and the Bose SoundLink Flex have different strengths. The Anker can play stereo content without downmixing it to mono and can get louder than the Bose. Its sound profile is more customizable thanks to the graphic EQ and presets featured in its companion app. It also has a longer-lasting battery life of over 15 hours, though this can vary depending on your usage. That said, the Bose is smaller, better built, and has a more neutral sound profile out of the box. It's also better for voice assistant support.
The Bose SoundLink Flex and the Ultimate Ears BOOM 4 are portable speakers that feature some key differences that can help you make your buying decision. The Bose features a more balanced sound profile that can more accurately reproduce the details of music and movies. It also has better controls and a built-in mic that works with the voice assistant on your iOS or Android device. That said, the Ultimate Ears is undoubtedly the better pick for outdoor use, thanks to its excellent directivity and much longer battery life. It can also get similarly loud without compressing as much.
The Bang & Olufsen Beosound A1 Gen 2 is a slightly better speaker than the Bose SoundLink Flex. The Bang & Olufsen offers a wider-sounding soundstage and comes with presets to tweak its sound to your liking. It also has fantastic voice assistant support with Alexa built-in, though it relies on your paired smartphone's Wi-Fi connection to work. That said, the Bose offers a better-balanced default sound profile and can get a bit louder. It also has a longer-lasting battery life, though this can vary depending on your usage.
The Bose SoundLink Flex is a better speaker than the Bose SoundLink Color II overall. The Flex is better built and has a better-balanced sound profile that can produce a more extended low-bass than the Color. That said, the Color has a longer-lasting battery life of almost 10 hours, though this can vary depending on your usage.
Though the Ultimate Ears WONDERBOOM 3 is a better speaker than the Bose SoundLink Flex, they have different strengths. The Ultimate Ears offers a wider and more spacious sounding soundstage. It also plays stereo content without downmixing it to mono, which is more immersive. It has less compression at max volume, so your audio quality sounds cleaner when you blast the speaker. On a single charge, it also has a significantly longer-lasting battery life of over 13 hours. On the other hand, the Bose SoundLink Flex can produce a deeper bass and supports voice assistants through your smartphone.
The Bose SoundLink Flex is a better speaker than the Sony SRS-XB33, though they have different strengths. The Flex is smaller, making it more portable. It has a better-balanced sound profile out of the box and has better directivity, so its soundstage sounds wider than that of the Sony. The Sony's sound profile is more customizable thanks to the graphic EQ in its companion app. It can also play stereo content without downmixing it to mono and has a longer-lasting battery life, though this can vary depending on your usage.
The Ultimate Ears WONDERBOOM 2 is better than the Bose SoundLink Flex, though they have different strengths. The Ultimate Ears is a stereo speaker with a more open and wide-sounding soundstage. It has less compression present at max volume and significantly longer-lasting battery life, though this can vary depending on your usage. However, the Bose can produce a deeper bass and supports voice assistants through your smartphone.
The Bose SoundLink Flex (2nd Gen) is a better speaker than the first-generation Bose SoundLink Flex. The 2nd Gen comes with an app that lets you EQ the sound to your preferences, support for AAC and aptX codecs (with compatible devices), and an improved control strip. That said, the first generation gets a little louder.
The Bose SoundLink Revolve+ II and the Bose SoundLink Flex perform similarly. The Revolve+ II offers a wider and more natural-sounding soundstage thanks to its 360-degree design. It also has a longer-lasting battery life, though that can vary depending on your usage. On the other hand, the Flex is smaller, and voice assistants from your paired smartphone are better at understanding your commands from far away and in noisy environments. It's better built, with an IP67 rating for dust and water resistance, and its default sound profile is also a bit more balanced.
The Bose SoundLink Flex and the Sony ULT FIELD 1 are comparable speakers with different strengths. They have very similar sound profiles, with the Sony offering a bit more warmth out of the box. You can also tweak the Sony's sound using the graphic EQ in its companion app. On the other hand, the Bose doesn't compress your audio as much when you blast your tunes. Both speakers will work with your device's Google Assistant or Siri voice assistant, but the Bose does a much better job picking up your voice from afar or in a noisy room. The Bose also lasts a little longer, but battery life varies with usage.
The Bose SoundLink Revolve II and the Bose SoundLink Flex have different strengths. The Revolve II offers a wider and more natural-sounding soundstage thanks to its 360-degree design. It also has a longer-lasting battery life, though this can vary depending on your usage. That said, the Flex is better built with an IP67 rating for dust and water resistance. It can also get a bit louder with a bit less compression present at max volume.
The Bose SoundLink Flex and the Ultimate Ears WONDERBOOM 4 are both portable speakers with different strengths. Because the Ultimate Ears has a 360-degree design, it has a much better soundstage performance: your audio sounds more or less the same from every angle. On the other hand, the Bose downmixes your audio to mono, and its drivers face forward. The Ultimate Ears also has a much lower Bluetooth latency than the Bose, so it's better suited to watching videos, but different apps and devices compensate for latency in different ways. On the other hand, only the Bose is compatible with your device's Google Assistant or Siri voice assistant, as the Ultimate Ears doesn't have a microphone. If battery life is a priority, the Ultimate Ears is your best bet, as it lasts six hours longer than the Bose.
The Bose Portable Smart Speaker is a better speaker than the Bose SoundLink Flex. The Smart Speaker offers a wider-sounding soundstage. It can produce a more extended low-bass and offers incredible voice assistant support with Alexa and Google Assistant built-in. It also comes with bass and treble adjustments to tweak its sound to your liking. That said, the Flex is smaller and better built, with an IP67 rating for dust and water resistance. It also has a bit less compression present at max volume, and you can pair it to two devices at once, so you can easily switch between audio sources.
The Bose SoundLink Flex is a better speaker than the Anker Soundcore 3 overall. The Bose has a better-balanced, more neutral sound profile and can produce a deeper bass than the Anker. It can also get a bit louder with less compression present at max volume, resulting in cleaner audio at louder volumes. However, the Anker has a longer-lasting battery life of over 13 hours. Battery life can vary depending on your usage, and your experience may differ.
Test Results
This is a small and sleek speaker that you place horizontally, either standing up or lying on its back. It also comes with a built-in strap to suspend the speaker from a hook. The speaker grilles are made out of steel, and the entire speaker is covered in thick silicone.
This speaker is remarkably portable. It's easy to bring with you thanks to its small and lightweight build, and it runs on battery power, so you don't have to plug it into an outlet to listen to your favorite tunes. This speaker comes with a small, thick strap on its side that you can use to suspend it from a hook or attach it to a bag.
The build quality is excellent. It's a sturdy speaker covered by thick silicone, and its drivers are protected by powder-coated steel grilles on its front and rear that are designed to withstand rust, so the paint doesn't flake off. It's rated IP67, certifying it to be fully dust-tight and immersible in up to a meter of water for 30 minutes. While the manufacturer doesn't specify an IK rating for impact resistance, the manufacturer advertises the Flex as rugged and able to withstand being dropped on the floor.
The Bose Flex has a great selection of simple controls. When you turn the speaker on, it informs you of its current battery level and the devices it's connected to. That said, while the buttons are simple to use, they're a bit hard to press compared to the Bose SoundLink Micro and Bose SoundLink Color II's controls because of the thick silicone covering the speaker.
- Power Button: Turns the speaker on/off.
- Volume Buttons: Adjusts the volume.
- Multifunction Button: Press once to play/pause your audio or answer a phone call. Press twice to skip to the next track and three times to skip to the previous track. Hold to decline a call or activate the voice assistant on your paired smartphone.
- Bluetooth Button: Press to activate Bluetooth pairing mode.
The Bose SoundLink Flex has reasonable frequency response accuracy. It comes with Bose's PositionIQ technology, which automatically adjusts the speaker's EQ according to its orientation. We tested it horizontally standing up. It has almost no low-bass, which isn't surprising given its small size, but die-hard fans of EDM might mourn the loss of that low-end thump. Still, the mid-bass is reasonably well-balanced, and a small boost in the high-bass adds warmth to basslines so mixes don't feel thin. Overall, it still has more bass on tap than similarly sized speakers, like the Ultimate Ears BOOM 4. The mid-range is virtually flat so dialogue is clear in podcasts and audiobooks, while instruments are rendered accurately and with detail in even busy mixes. The treble range is also well balanced, with a slight roll-off in the high-treble that doesn't hurt vocal intelligibility or mix clarity. Ultimately, this speaker is suitable for listening to a variety of different audio content.
Its soundstage performance is middling. On its own, this speaker is only capable of playing mono audio, and its directivity is limited to the direction it is pointing in. That means your audio won't sound especially immersive or enveloping, and you might miss out on some details in your audio like reverb and delay tails. You can hook up a second unit to get stereo playback but, even then, this isn't a speaker to choose if 360-degree sound is important to you: its audio reproduction changes greatly depending on your angle to it.
This speaker has acceptable dynamics performance. It gets loud enough to fill a typical living room with sound, but there is a fair bit of compression in the bass region when you push it to its max volume. It won't get loud enough to fill up larger or more open spaces.
This speaker has a fair battery performance. It's advertised to last around 12 hours from a single four-hour charge. However, in practice, you'll get closer to seven hours of consistent playback. On the upside, charging is faster than advertised: it took us just under three hours to reach a full charge. That said, battery performance can vary depending on your usage, so your experience may differ. There's also an 'Auto-Off Timer' power-saving feature you can program to shut the speaker off automatically following 5, 20, 40, 60, or 180 minutes of inactivity.
The Bose SoundLink Flex doesn't have any built-in voice assistants. If you want to control it with your voice, pair a smartphone with Google Assistant or Siri to the device. It doesn't struggle to hear your commands, even if you're in the middle of a noisy party or if you're further away from the speaker itself. Importantly, this feature isn't available if you purchase the SE variant of this speaker since it comes without a microphone.
The Bose Connect app is okay. It's compatible with both iOS and Android devices, and you can use it to pair the Bose SoundLink Flex to another Bose speaker to create a stereo pair. You can even link up multiple other compatible Bose speakers and soundbars when you want your audio to fill a large room. Unfortunately, unlike the Bose SoundLink Flex (2nd Gen), it lacks sound customization features like a graphic EQ and presets, so you can't tweak its sound to better suit your preferences. The Anker Soundcore Motion 300 is another similar speaker with more sound customization tools.
This speaker doesn't have any inputs. There's only a USB-C port to charge it. If you're looking for a Bose speaker with an AUX input, it's worth checking out the Bose SoundLink Mini II Special Edition. Or you can check out the Beats Pill, which can playback lossless content via a USB-C connection.
This speaker has great Bluetooth connectivity. You can pair it with up to two devices simultaneously, meaning you can switch between using your phone and laptop as an audio source in no time. Latency with iOS and Android devices is slightly high, though, so it's not ideal for streaming videos and movies as you may notice some lip-synching issues. That said, different devices and apps compensate for latency differently.