Monitor Audio Airstream S150 review – simple charms

Monitor Audio, the British loudspeaker manufacturer, has been around for more than four decades now, but recently it’s been channelling all that expertise into making much smaller, mains-powered Bluetooth speakers. The Audio Airstream S150 is one of its latest products, and shares the same design as its similarly-sized brother, the Airstream S200, but doesn’t come with the S200’s Apple AirPlay support. 

The first thing you’ll notice is its distinctive design. It’s predominantly tower-shaped but with a top that slopes and angles backwards. It looks a bit like a loaf of sliced bread that has been squashed in the freezer. You have a choice of either charcoal grey or white two-tone finishes. The white model I reviewed had a front covered in a light grey speaker cloth whereas the charcoal grey model has a black speaker cloth. Both look equally smart.

Aside from its intriguing shape, the design is pleasingly simple. Below the top power button, there’s an LED that lights up blue when pairing or connected over Bluetooth, or green when you’ve set it to the 3.5mm auxiliary wired connection. The S150 can retain five Bluetooth devices in its memory, but it won’t swap over to the 3.5mm input automatically when it detects a signal like some other speakers, so you’ll need to press the source switcher button on the side. There’s another button here for setting it back to Bluetooth or setting up the pairing. There are also side controls for adjusting the volume. 

The one thing the S150’s lacking is any kind of media playback controls, so you’re not able to pause or skip tracks directly from the speaker, which is a shame. Instead, it means you’ll need to keep your Bluetooth-connected audio source close at hand, as there’s also no remote control included either.

On the back, alongside the 3.5mm input, there’s a USB port that can be used for charging devices. It outputs 5V/1A, so will slowly charge most smartphones, but tablets typically require at least 2 amps. The USB port is also not powered when the speaker is in standby, which is a little annoying. 

The front speaker cover can be removed if you want a look at the drivers. Once taken off, you’re greeted by a 1in dome tweeter with 3in bass drivers directly above and below. Upon closer inspection you’ll see that the two bass drivers are actually angled slightly left and right, rather than directly forward. This helps to disperse the sound across a wider soundstage, making the speaker sound far wider than you would expect from a solitary tower-shaped loudspeaker. There’s also an auxiliary bass radiator on the back to help out with its lower frequencies.

The two bass drivers output 25W each, whereas the central tweeter outputs 10W. While the S150’s frequency response of 80Hz – 25kHz might leave you feeling slightly worried for the lower-frequencies, the reality is that there’s a rich, weighty low-end. Listening to my bass test tracks of choice A$AP Rocky’s L$D and The Toure-Raichel Collective’s Tidhar there was plenty of deep, controlled thump to the bass, far exceeding what I expected for a speaker of this size.

The mids and trebles were also suitably delicate and not overly-impacted by the emphatic bass. The sound isn’t as detailed as other mains-powered Bluetooth speakers we’ve tested such as the Bowers & Wilkins T7, for instance, but the T7 also costs twice as much as the S150, so to even come close is commendable. Another track, Menahan Street Band’s Make The Road By Walking, also allowed us to pick out all the individual delicate percussion and brass instruments.

Likewise, regardless of whether we set the speaker to a low volume or pushed it to maximum, the S150 remained neutral and controlled throughout, and resisted veering towards any muddy or overly bright sounds at either end of its frequency range. Its maximum volume didn’t distort either, and it could easily fill a large room, which is surprising for considering the speaker’s size.

The Airstream S150’s outstanding simplicity grants it a certain overall charm. It’s completely unfussy in both its design and use, and if all you want is an easy way to play music from a wired or Bluetooth source with fantastic sound quality and a more than reasonable price, it’s a tough one to beat. If you’re desperate for AirPlay, then the Airstream S200 is also worth a look, but it is £50 more expensive. For our money, we’d rather stick with the S150, as it’s cheaper and sounds fantastic across a variety of different genres. It’s a Best Buy.