Bluesound Pulse Flex review: Outstanding app control sets the benchmark

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For a short while, Bluesound was the only name in the 'wireless hi-res audio streaming game', but it's safe to say those days are gone.

Like all the best innovators do, though, the company has remained at the forefront and generally is extremely competitive when compared to the raft of imitators it has inspired.

The Pulse Flex wants to be Bluesound's latest demonstration that it's nowhere near losing its mojo… so how does it fare?

The Bluesound Pulse Flex went on sale at the very end of last year, and in the United Kingdom it's priced at £279. It will cost you $349 in the United States, while it goes for AU$549 in Australia.

The world, I hardly need to tell you, is far from short of wireless speakers that sell for this sort of money – but then Bluesound has been a front-runner for quite some time now.

For a brief moment back there, Bluesound had a unique selling point: wireless streaming of genuinely high-resolution digital files. Others have caught up, of course, but the fact remains that a (relatively) affordable wireless speaker with 24bit/192kHz PCM and DSD256 streaming possibilities from multiple sources really should be a product to be reckoned with.And getting that big hi-res content on board can be done in quite a few different ways. The BluOS control app will let you integrate literally dozens of different music streaming services – and its compatibility with (for instance) the 'Connect' versions of Qobuz, Spotify and Tidal makes accessing content as simple as can be.

In addition, the fact the Pulse Flex is Roon Ready, works with AirPlay 2, and offers plenty of options where internet radio is concerned too, only adds to its flexibility.Using the app utilises the integrated dual-band Wi-Fi, of course – but there's additional wireless functionality available in the shape of Bluetooth 5.3 with aptX HD codec compatibility. And on the rear of the speaker there's an Ethernet socket, just in case ultimate network stability is a priority.

You'll also find USB-A and USB-C slots here, as well as a hybrid 3.5mm socket that can either be an analogue or a digital audio input. If you favour the second option, Bluesound supplies a Toslink/3.5mm adapter in the packaging. All incoming digital information is dealt with by a DAC that is, sure enough, good up to DSD256 and 24bit/192kHz PCM resolutions, before having a rocket put up it by 50 watts of Class D amplification.

Bluesound has finessed this power using its 'Smart DSP', and it serves 10 watts to a 21mm tweeter and 40 watts to a 102mm mid/bass driver. Bluesound is not exactly making with the details here – nothing about frequency response or even the material used in the construction of these drivers is forthcoming. At least it's prepared to confirm that both drivers face forwards, though.

Thanks to the BluOS control app, it's a doddle to set up the Pulse Flex and get at the content you want, whether it's internet radio, your favourite music streaming service(s) or stuff stored on a common network. And once you got it, there's a whole lot to enjoy about the way the Bluesound serves it up

What's probably most immediately striking is just, well, how immediate this speaker sounds. Its presentation is remarkably open when you consider what a small cabinet this is, and there's a kind of direct and unequivocal character about the Pulse Flex's delivery that's very engaging.

Detail levels are high, which helps with the impression of positivity (which is especially noticeable when you're listening to nice big 24bit/192kHz or DSD64 audio files), and the evenness of the frequency response from the bottom end to the top also allows the Bluesound to present music in a fairly naturalistic manner.The tonal balance is nicely judged, and much more than many price-comparable rivals the Pulse Flex seems perfectly happy to get out of the way of a recording and express it without sticking its oar in too much. This kind of egoless attitude is not all that common in this area of the market – many alternative designs want to meddle with the sound of a recording, and it's seldom a helpful attitude.

The neutrality of the Bluesound, combined with its relatively open and revealing nature, goes a long way to convincing you that you're getting an uncorrupted account of the music.

It controls low-frequency information well, which allows for good momentum and a confident way with rhythmic expression. This speaker doesn't over-egg bass sounds, which might initially seem less than exciting – but it doesn't take all that long in the company of the Bluesound to realise it strikes a more convincing overall balance than is usual in a product of this type.

There's a reasonable amount of dynamic headroom available, so big shifts in attack or intensity are more than alluded to – but where the Pulse Flex really scores in this regard is with the attention it pays to low-level dynamic variations. The ability to identify and confidently contextualise the harmonic fluctuations and transient occurrences in a recording adds no end to the impression of 'the complete picture'.Really, about the only meaningful way in which the Bluesound could up its game is when it comes to the sort of energy and excitement it rather seems to think is a bit beneath it. The speaker's attitude of careful attention to detail and tonal neutrality is all well and good almost all the time – but when it comes up against the 'wrong' sort of music (music that values drive and posture over all else) the Pulse Flex can sound just a little undemonstrative and dispassionate.

Still, for most listeners a hint of the 'matter of fact' is going to be preferable to 'eyes out on stalks' – if that's a choice that needs making then I know which side I'm on.

Display screens or other design fripperies are not for Bluesound. The Pulse Flex is a discreet and quite unassuming speaker in visual terms, with only the softly cornered triangular prism of its shape offering the merest hint of 'design'.

It's an understated looker no matter which of the three finishes you choose – black-and-charcoal or white-and-grey are available as alternatives to the white-and-tan of my review sample – and its compact 196 x 131 x 111mm (HxWxD) dimensions mean it's not difficult to position.

Bluesound offers a range of stands and wall-mounting accessories, but the integrated soft rubber foot on which the speaker rests means it's equally secure on a shelf or desktop. The standard of build and finish is not up for question – though it's probably fair to say that this is not the most tactile speaker around.

Operating the Pulse Flex as a standalone mono speaker can be done in a few different ways. Integrating it into Amazon Alexa Skills in order for a truly smart speaker to offer some voice control is not especially elegant, but it's an option.

There are some control buttons on the plastic top plate: volume up/down, play/pause and skip forwards/backwards are all available here, along with three buttons offering shortcuts to favourite playlists, radio stations or what-have-you.

BluesoundYou can specify your shortcuts in the BluOS control app, and it's a feature that goes some distance towards explaining Bluesound's position in the market. For an app that offers such a granular level of control, it's remarkably easy to navigate, and logical and stable in operation.

In the decade or so that BluOS has been a thing, increasing numbers of third-party manufacturers have come aboard – which means that if you want to use your Pulse Flex as part of a home cinema surround-sound system or a multiroom set-up, say, you're by no means limited to other Bluesound products as partners.

The app makes setting up even quite complex and/or wide-ranging wireless set-ups simple, too – which is not something that can't be said for quite a number of competing systems. I really think this app is at the cutting edge.

Bluesound's status as a front-runner of hi-res streaming is only going to be enhanced by the Pulse Flex – it's a great-sounding speaker with a brilliant control app, and the sort of wider-system flexibility that means it could be at the heart of your wireless set-up for the long haul.

The Audio Pro C10 mkII is bigger than the Pulse Flex, both physically and in terms of its power output – and it's a little more expensive too. But its sound is clean and open, punchy and assertive – and it's got a bit going on where 'Scandi Design' is concerned, too, as long as you like monochrome. The control app makes setting up a multiroom system to include the C10 mkII straightforward enough, but like every competitor it's playing second fiddle to the BluOS alternative the Bluesound is running.