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A big speaker for the money, but one that offers too little in the way of audio performance and claimed battery life.


  • Goes pretty loud
  • Can be used as a power bank


  • Audio performance is mediocre
  • Battery life doesn’t meet expectations
  • Plain looks


  • UKunavailable
  • USARRP: $79.99
  • Europeunavailable
  • Canadaunavailable
  • Australiaunavailable

Key Features

  • IPX7 ratingWater and dust proof
  • StrapEasy to carry around
  • TWS modePair two together for proper stereo


With its chunky build and optional strap, Monoprice’s Harmony Capsule 300 is a Bluetooth speaker that’s ready to go.

Promising long battery life, a waterproof chassis, 30W of power, and the ability to charge your phone off it, the Capsule 300 looks like a tempting proposition on paper, especially when you consider it costs just $80. So does it perform well enough to earn a space on your next camping trip?


  • Only comes in black
  • Big and heavy
  • Strap included

Like Monoprice’s smaller, cheaper Capsule 200 Bluetooth speaker, the 300 also bears quite the resemblance to something made by JBL, although this time it’s a cross between the Charge 5 and the Xtreme 3. The Monoprice is blander than either of those, though, lacking any real design flourishes. Plus it’s only available in black.

The Capsule 300 is a pretty hefty thing, about the size of a two-litre Coke bottle, with a rubber plinth incorporated into the base to keep it upright. It weighs just over 1.5kg – about the same as a 14-inch MacBook Pro – so it’s not something you’ll want to ferry around a lot, but it feels like it could withstand being knocked about a bit in transit.

Monoprice Capsule 300 carry strap
Image Credit (Trusted Reviews)

When you do need to move it from A to B, it comes with a strap that can be attached to metal rings above the passive bass radiators at each end, which gives it a slightly old-school boombox vibe. The carabiner-style clips feel sturdy and well-built, but the glossy material the strap itself is made of feels a bit on the cheap side, like something you’d find on a budget laptop bag – hardly befitting the rugged styling of the rest of the speaker.

The drivers are covered with a dense black mesh that picks up detritus pretty easily, with a rubberised plastic bar across the top that houses a set of decent-sized buttons. These allow you to control playback, volume and power, switch between sources, and activate the TWS stereo pairing mode. You need a second speaker for this so I wasn’t able to test it.

On top you’ll also find a set of four lights that indicate how much battery is left, plus a separate LED strip that seems to flash pointlessly the whole time the speaker is powered on, which just seems like a needless waste of juice.

Monoprice Capsule 300 buttons
Image Credit (Trusted Reviews)


  • IPX7 rating
  • Doubles as a battery
  • Micro USB charging
  • Battery doesn’t match claims

The Capsule 300 backs up its rugged looks with an IPX7 toughness rating, which means it’s protected against dust and you can dunk it in water to wash it off without having to worry about breaking it.

Underneath you’ll find a chunky rubber panel that can be removed to reveal its three ports: 3.5mm for going wired, USB-A for using the Capsule 300 as a massive power bank, and micro USB for charging the battery. That’s quite an old-fashioned line-up, but being able to share its battery is definitely handy.

Monoprice Capsule 300 ports
Image Credit (Trusted Reviews)

The aux port seems increasingly unnecessary with headphone sockets becoming harder and harder to find, though, and charging a newly released speaker by micro USB in 2022 feels like a real blast from the past. Nobody’s expecting all the very latest tech for $80, but would USB-C have been too much to ask for?

There are two 5000mAh batteries inside the Capsule 300, which is about twice as much power as you get inside most smartphones. According to Monoprice that should correspond to as much as 30 hours of playback at 50% volume, but I got just over 16 at less than that. That’s still a fairly useful innings, but way short of the numbers claimed.

With such a big battery to fill it also takes an absolute age to charge. Again, Monoprice claims it should take about six hours, but even when left plugged in overnight it never seemed to reach full capacity, with the fourth red LED always blinking as it if hadn’t quite finished. When connected to a MacBook Air, macOS’s battery gauge for connected devices had it down as only being 90% charged. 

Monoprice Capsule 300 on the ground
Image Credit (Trusted Reviews)

Wireless connectivity comes in the form of Bluetooth 5. Range isn’t bad, although put a wall or two in the way and it’ll start to cut out long before you reach the theoretical 10-metre limit. Considering it’s clearly designed to primarily be used outside that shouldn’t be too big a problem. It doesn’t support multipoint pairing either so you’re limited to connecting one device at a time.

The fairly modest feature set is completed by an onboard microphone, which does a decent enough job of picking up voices but no more than that. It’ll do for the odd call or setting reminders via your phone’s voice assistant.

Sound Quality

  • Lacks musicality and life
  • Timid bass

Monoprice has armed the Capsule 300 with 30 watts of power and two 2.5in drivers. They’re both positioned on the same side, so you’ll need to have it pointing towards you to hear it at its best.

Monoprice Capsule 300 side detail
Image Credit (Trusted Reviews)

That’s important because the Capsule 300’s best is pretty average. While it certainly doesn’t lack volume, there isn’t a huge amount of detail or depth to the sound. The percussion in Speed Trials by Elliott Smith sounds thin and muted, with all the instruments squeezed together rather than being given space to breathe.

It sounds better when given Ball and Biscuit by The White Stripes but the guitars still lack texture and the drums could do with a bit more oomph, while the bass line in Mac Miller’s Ladders isn’t as taut or bouncy as it’s supposed to be. Of course, you have to take the Capsule 300’s price into account when judging its performance, but for a speaker of its size you’d expect better, especially from the bass.

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Should you buy it?

If you want something cheap and cheerful. While the price of the Capsule 300 still isn’t spare change, it’s cheap enough to be relatively expendable. If you want something that you don’t have to worry about looking after, perhaps for the kids or the garden, it could be an affordable option.

If sound quality is a priority. To a lot of people the Capsule 300 will sound just fine. Not everyone needs high-end performance and it goes pretty loud, but you don’t need to be an audiophile to hear the shortcomings in its performance.

Final Thoughts

If you’re looking for something relatively expendable that goes loud and won’t mind a bit of mistreatment, the Capsule 300 certainly has its benefits, but if audio quality is more than a secondary consideration you can find something smaller that sounds better for a similar price.

The Capsule 300 feels like the kind of speaker you might buy for festivals or other situations where if it was damaged you wouldn’t feel it too much in the pocket. In almost any other circumstance, there are better alternatives out there.

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We test every wireless speaker we review thoroughly over an extended period of time. We use industry standard tests to compare features properly. We’ll always tell you what we find. We never, ever, accept money to review a product.

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Tested for a week

Tested with real world use


Can I connect the Capsule 300 to multiple products simultaneously?

The Capsule 300 doesn’t support Bluetooth multipoint, so can only be connected to one product at a time.

Full specs

IP rating
Battery Hours
Size (Dimensions)
Release Date
Model Number
Driver (s)
Audio (Power output)
Frequency Range
Speaker Type


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As part of this mission, whenever we review a product we send the company a series of questions to help us gauge and make transparent the impact the device has on the environment.

We currently haven’t received answers to the questions on this product, but will update this page the moment we do. You can see a detailed breakdown of the questions we ask and why in our sustainability info page.

Jargon buster


Bluetooth is a method of wireless transmission that allows for the exchange of data between devices over short distances.

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