We found the full-size Soundbook to be a bit of a let-down for its £250 recommended price tag, but the Soundbook Go is offered at a much more palatable £80.
It's lost a few features in the shrinking and cheapening process – you won't get the aptX high-quality streaming support and FM radio the big version has.
But with up to seven hours of continuous speaker playback from the battery, and a microphone for conference, calls it's competitive for features with similar portable speakers, such as the Logitech UE Mobile Boombox.
It's very similar to the big SoundBook in terms of design, too. The odd slanted shape means it won't stand straight upright unless you open the cover on the front and fold it around into a stand.
The shiny exterior edges of the SoundBook Go are plastic, but slick and high quality, with most of the back covered in the same leathery material as the cover. The controls are limited to just volume adjustments and a power button.
Not that you need to use the latter of those, as the SoundBook Go turns on when you open its front flap, revealing the speaker grille, and turns off when you close it.
It's a simple design that works well, and it didn't have any problems reconnecting quickly during my time with it. Just open and it's ready to play music from your phone.
Pairing with your device can be done the old fashioned way (pressing a button to put it in pairing mode) or via NFC. You just hold a compatible phone against a spot on the back of the SoundBook Go and confirm the connection on-screen.
Of course, the most important part is what happens once you're actually playing music, and the results from its 15W speakers aren't bad.
The SoundBook Go offers music that's nicely balanced, punching out a good amount of bass for its size, along with a bright top end to create a fairly complete soundstage where nothing gets obviously lost.
Detail isn't bad either, with things like individual cymbal crashes usually audible, and voices crisp and clear.
However, it isn't perfect. While I was pleased to hear a fairly balanced sound coming from the Go, there's definitely a compression and lack of richness to it.
The compression is sometimes noticeable at medium or lower volumes, but if you start to crank up the SoundBook Go (it can get fairly loud) you'll really hear both the treble and bass being crushed and distorted, with detail in the bass particularly losing out.
Despite decent detail and balance to the sound at normal volumes, there's also no denying that its sound is thin compared to what a larger speaker gets you.
For a portable speaker of its size, none of this is surprising, but there are portable speakers (such as the Cambridge Audio Minx Go) that aren't much bigger which offer the same soundstage without the degree of flatness this has – the music is that much more energetic.
Yes, the trade-off is size and weight, but if what you're after is nice-sounding audio, that's a trade-off you'll have to consider.
The Bayan Audio SoundBook Go is a brilliantly smart and slick little speaker, with some nice features and great portable design. I was pleasantly surprised by how balanced the sound it has to offer was too.
However, there's no avoiding that you just don't get the life and richness from your music that you can with something a little bulkier. It's not a bad buy for its price, but unless the smaller size and portability are paramount for you over the overall sound quality, there are better speakers available.