(Image credit: Marshall)

Marshall has created a new version of its impressive Middleton portable Bluetooth speaker, which promises a significant audio upgrade.

As before, it takes its design cues from the firm's legendary guitar amplifiers, and like those amps it's a little heavier than we'd like – but the original model delivered excellent audio, and the new version is claimed to be even better.

In our original Middleton review, we praised its "extremely solid" sound and "classy, classic" style. This new version has much longer battery life – 30 hours, up from 20 – and provides 360-degree stereophonic sound with some significant improvements.

(Image credit: Marshall)

Marshall Middleton II speaker: key features and pricing

The Middleton II has IP67 dust and water resistance, and like its predecessor it's built tough. It's the kind of speaker that if you drop it you'll be more worried about damaging the floor than the speaker.

There's a built-in mic for hands-free calling, and it uses Marshall's multidirectional control knob for easy navigation and adjustment. Bluetooth is 5.3 with LE audio support and multipoint.

There are two key differences that I'm interested in hearing. The first is that this second-generation product delivers deeper bass than the first generation, which is always welcome in a modestly-sized speaker like this one. Its low end is 45Hz compared to the 50Hz of the first-gen.

The second is what Marshall tells us is "more refined sound at max volume". That's a big deal for me, because while I really like the Marshall sound in the few Marshall speakers I've tested, I've found them to get a little messy at the high volumes I prefer for music playback.

So the prospect of a Middleton that's got bigger bass and clearer audio at full pelt is music to my ears.

The Marshall Middleton II will be available from 15 July for £259.99 / $329.99 / €299 (about AU$542).