JBL Xtreme 4 Review

JBL refreshes its portable Bluetooth speakers at an irregular pace, rotating through the range, and almost three years after the Xtreme 3 the Xtreme 4 arrives to shore up the strengths of this fairly hefty speaker. This review is based on that published test, not on a hands-on trial of our own.

A touch larger than its predecessor, the Xtreme 4 measures close to 30 centimetres long by 149mm high and 141mm deep, and delivers 100W of nominal power. It is portable, but a rucksack is the sensible way to carry it, as its 2.1kg — 200 grams more than the Xtreme 3, whose design it largely inherits — soon makes itself felt. JBL has stuck with an elongated, capsule-like shape whose ends are narrower than the middle; there is no choice about orientation, as it only sits horizontally, but a pair of rubber bars keeps it planted and it never feels as though it might roll away. Three colours are offered — black, blue or camouflage — and each ships with a matching carry strap, justified by the speaker's bulk, clipping to two attachment points on top that frame the controls.

Those controls now sit in two rows — power, playback, Bluetooth pairing and volume up and down — and are easy to tell apart. The connectivity, though, disappoints: a single USB-C port on the back, used only to charge the battery. That is a step back from the Xtreme 3, which also had USB-A and a line-in. On the plus side, the USB-C works both ways, so the Xtreme 4 can double as a power bank, and JBL deserves credit for a user-replaceable battery, tucked under the speaker behind a two-screw hatch — though it is not yet sold separately, so a replacement means contacting support.

For most people Bluetooth is what matters, and here JBL moves to the 5.3 standard; there is no Wi-Fi, unlike some boomboxes. A stereo mode is on hand, and any JBL speaker can be linked over Auracast to play the same track in several rooms. Auracast is one of many features, alongside multipoint Bluetooth and unusually rugged construction: JBL claims an IP67 rating, with resistance to splashes and dust and full immersion to one metre for 30 minutes, though it is not shockproof. The JBL Portable app adds a 5-band equaliser, firmware updates, the party mode for linking speakers and a "playtimeboost" setting meant to stretch the battery.

That battery is one of the big upgrades: JBL quotes 24 hours, up from 15 on the Xtreme 3, with charging cut to 3.5 hours from four, and all without piling on weight. Playtimeboost is supposed to extend things further but noticeably degrades the sound and feels unnecessary, since JBL's own figure was comfortably beaten in testing — more than 32 hours. At that level nothing else comes close, and several days of use between charges is realistic. The one real gap is codecs: there is still no high-quality option, only SBC and AAC, despite a driver array of two 7cm woofers for the bass and mids and two 2cm tweeters for the treble, with a rated frequency response of 44 Hz to 20,000 Hz.

That array is tasked with the familiar "JBL signature sound" — a reference point for some, a byword for overbearing bass for others. The truth here sits in between. Bass is undeniably JBL's weakness for indulgence, and there is a strong low-end presence on virtually every track, but it is at least precise and lends genuine warmth to orchestration. For some ears, in some rooms, it can feel excessive, and the equaliser is then worth reaching for to find a more neutral balance. The classic JBL flaw — low-mids swamped by bass — is present, though voices are essentially never buried, and the treble fares well through those two comfortable tweeters, striking a pleasant balance, if with a faint hint of sibilance.

The Xtreme 4 is also a speaker built for volume: let it whisper at under 30 per cent and the flaws grow more obvious. Push past 70 per cent, though, and the bass turns muddier, the overall sound losing precision and gaining a harder edge — nothing disastrous, but worth knowing before you lean on it as a party speaker.

A sturdy speaker made for adventurers who cannot do without decent sound, the Xtreme 4 is inevitably far bulkier than a Flip or a Charge. It offers remarkable power and a genuinely astonishing battery life, whether measured against the Xtreme 3 or today's rivals, and its build — IP67 rating included — is reassuringly robust. The loss of the line-in is a shame, but Bluetooth is what most people use now and it works flawlessly, bar a pronounced latency that rules out gaming audio. The sound still carries that JBL character, its bass perhaps a little too forward, but happily that can be dialled back. All told, a very well-made speaker, held back only by a price that sits above much of the competition.