This is the English edition of a review from my Japanese YouTube channel, iestaLife. I review gadgets from my home studio in Japan, so product links go to Amazon Japan.
Quick take
I use a JBL GO4 in the shower, and I tried the MIATONE MagBoom mini, a waterproof Bluetooth speaker that snaps onto the back of an iPhone with MagSafe. They cost about the same. The GO4 wins on bass and maximum volume. The MagBoom mini wins on convenience: it doubles as a phone stand and sticks to any wall a magnet will hold on.
What I tested
- MIATONE MagBoom mini (4,780 yen, 4,302 yen with a coupon at the time of recording)
- JBL GO4, which I already use in the bathroom
- An iPhone 17 Pro Max, with the speakers compared at roughly matched volume
What I found
- The MagBoom mini is about the size of a MagSafe puck and feels more premium than I expected, with a metallic-looking top.
- On the back of the iPhone it works as a stand at a comfortable viewing angle. The magnet holds the phone even when you lift it by the speaker.
- Sound is like a louder iPhone speaker: clearly louder and cleaner than the phone itself, but light on bass.
- The GO4 has noticeably more bass, and at maximum volume it is much louder.
- The MagBoom mini's USB-C port has no cover. Charging is easy, as long as the port is dry first.
- The maker lists 12 hours of playback from a 3-hour charge and a weight of 90 g.
Comparison
 MagBoom mini |  JBL GO4 | |
|---|---|---|
| Bass | Light | Full |
| Max volume | Clearly louder than an iPhone | Much louder than the MagBoom mini |
| MagSafe | Yes, works as a stand | No |
| Charging port | No cover | No cover |
Who it's for
- MagBoom mini: people who watch videos in the bath, want a stand, or want one less thing to carry
- JBL GO4: people who mainly listen to music and want volume to beat the shower noise
Watch the video
The video is in Japanese, but the sound comparison starts at about 9:40, so you can hear both speakers for yourself.
Limitations
In the sound comparison I adjusted the levels to match, so it compares tone rather than loudness. I did not measure battery life. Prices are in yen from Amazon Japan at the time of recording.
Products
MIATONE MagBoom mini: on Amazon Japan
JBL GO4: on Amazon Japan
The Amazon Japan links above are affiliate links. As an Amazon Associate, I earn from qualifying purchases. Check the listing for the exact model, current price and shipping availability in your region.
More reviews in English
All Earbuds, Speakers & Audio (35) →Browse all English reviews →
This review is also available in Japanese.