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Amazon UK • Updated 08/11/2025
Quick Specs
Our Verdict
The JBL Partybox Stage 320 delivers powerful 240W sound with excellent audio quality, practical wheels for transport, and an 18-hour battery. Whilst large, heavy, and expensive, it excels as a party speaker for those who prioritise volume and sound quality.
Pros & Cons
Pros
- Excellent sound quality
- Powerful 240W output
- Numerous functions and effects
- Easy to operate
- Removable battery for quick replacement
- 18-hour battery life
- Wheels and telescopic handle for transport
- Bass-Boost with three modes
- Light show with app control
- Microphone and guitar inputs
- Effect Lab with customisable sounds
Cons
- Large and heavy (16.5 kg)
- Expensive (nearly £600)
- IPX4 rating inferior to some competitors
- Shorter battery life than Sony ULT Field 7
- Companion app proved unreliable
- Design aesthetics debatable
Full Specifications
Key Features
Excellent sound quality
Powerful 240W output
Numerous functions and effects
Easy to operate
Removable battery for quick replacement
18-hour battery life
Introduction
The JBL Partybox Stage 320 is a large, powerful party speaker designed to deliver impressive sound at outdoor gatherings and large indoor events. With its 240W output power, 18-hour battery life, and practical wheels for transport, it's built for those who take their parties seriously.
When I recently tested the Sony ULT Field 7 party speaker, I remarked on its considerable size and weight. However, upon unpacking the JBL Partybox Stage 320, the Sony speaker suddenly seemed rather compact by comparison.
This is because the Partybox Stage 320, measuring 33.5 × 67 × 38.5 cm and weighing 16.5 kg, is a genuine heavyweight. The Sony speaker weighed a mere 6.3 kg in comparison.
Design and Build Quality
The Partybox Stage 320 isn't designed to be carried about like the Sony speaker. Instead, it features two wheels and a handle, allowing you to pull it along behind you like a large suitcase. The design may resemble a public waste bin, but ultimately it's function that matters—and in this regard, the Partybox Stage 320 delivers.
Just like the ULT Field 7, the Partybox Stage 320 is a party speaker intended for larger groups rather than small picnic gatherings. With 240W of output power, the Partybox is loud and commanding. At full volume, the speaker quickly attracts attention—including from your neighbours.
Sound Performance
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The Partybox doesn't just sound loud—it sounds genuinely excellent. The audio is remarkably clean and clear, though the emphasis is naturally on delivering deep, powerful bass.
Like the Sony Partybox with its ULT button, the Partybox Stage 320 features a button allowing you to quickly and easily boost the bass. Here, this function is called Bass-Boost, offering three modes: "Deep", "Powerful", and "Off".
The intended party use is enhanced by the light show on the front panel. This lighting can be controlled via buttons on the speaker's top or through the companion app. If desired, you can disable the light display entirely.
Functions and Effects
Contributing to the party atmosphere is a feature called Effect Lab—a series of sound effects that can be triggered either via the app or three pre-programmed buttons on the speaker. Effects include "Repeater", "Echo", and "Wipeout", along with cheerful exclamations such as "Let's party!".
I find most of these effects rather silly and even slightly embarrassing, though this is a matter of personal taste. With a connected microphone, you can even make your own mood-enhancing announcements. An electric guitar can also be connected to the Partybox Stage 320, with the speaker serving as an amplifier.
Controls
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On the speaker's top are controls for adjusting volume, starting and stopping playback, and managing connected microphones or guitar. This allows the speaker to be controlled easily and conveniently without the companion app—which proved fortunate during testing, as the app was unreliable and frequently lost connection to the speaker.
Large, Heavy, and Expensive
If you're willing to transport the Partybox Stage 320, the speaker can provide powerful sound and suitable effects for your party. However, you'll need to part with nearly £600 for this privilege. In return, you get better and more powerful sound than the Sony ULT Field 7, which costs nearly as much.
In direct comparison to the ULT Field 7, the Partybox Stage 320 falls short in certain respects. Battery life is lower—whilst the Partybox Stage 320 runs out after 18 hours, the Sony ULT Field 7 can play for up to 30 hours. The JBL speaker's IPX4 rating (splash-proof) is also significantly behind the Sony speaker's IP67 rating, which protects against temporary submersion.
On the other hand, the Partybox Stage 320 features a removable battery—a practical feature for recharging and continuing the party quickly.
All in all, the JBL Partybox Stage 320 fulfils all expectations of a party speaker.
Pros and Cons
What We Liked
- Excellent sound quality
- Powerful 240W output
- Numerous functions and effects
- Easy to operate
- Removable battery for quick replacement
- 18-hour battery life
- Wheels and telescopic handle for transport
- Bass-Boost with three modes
- Light show with app control
- Microphone and guitar inputs
- Effect Lab with customisable sounds
What Could Be Better
- Large and heavy (16.5 kg)
- Expensive (nearly £600)
- IPX4 rating inferior to some competitors
- Shorter battery life than Sony ULT Field 7
- Companion app proved unreliable
- Design aesthetics debatable
Verdict
The JBL Partybox Stage 320 is a powerful party speaker that delivers outstanding sound quality and impressive volume for large gatherings. Its 240W output ensures it can fill sizeable spaces with clear, bass-heavy audio that will energise any party.
Whilst it's undeniably large and heavy, the inclusion of wheels and a telescopic handle makes transport manageable. The 18-hour battery life should suffice for most events, and the removable battery design means you can quickly swap in a fresh one if festivities continue.
The sound effects and light show add to the party atmosphere, though some may find them gimmicky. The ability to connect microphones and guitars extends the speaker's versatility beyond simple music playback.
At nearly £600, it's a significant investment, but for those who regularly host large gatherings and prioritise sound quality above all else, the JBL Partybox Stage 320 represents excellent value.
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