One of the most immersive portable speakers I've tested is not made by Bose or Sonos

Allow me to paint a picture.

After unboxing the Tronsmart Mirtune S100 Bluetooth speaker, I turned it on, opened my Pixel 9 Pro, went to "Connected devices," walked through the process of connecting the speaker, and then opened Spotify to my go-to test playlist.

Also: This tiny Bluetooth speaker is the loudest I've heard - and it's not made by Bose or Beats

The volume on my phone was set to around 50%, which is a pretty good level for testing speakers. I tapped play on "Analog Kid" by Rush and was punched in the face with a wall of sound. 

I hadn't expected such volume from a small speaker, but there it was. You'd have thought my phone was cranked to 11, and the band was right in front of me playing live.

I quickly grabbed my phone and turned down the volume to roughly 25%, but the speaker was still pretty loud. Next, I opened my decibel meter, cranked the volume back to 50%, and the meter read 86 decibels.

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According to Decibel Pro, "85 decibels is a high noise level on the decibel scale. It is 15 times more intense than the 70-decibel level considered by the World Health Organization (WHO) and Environmental Protection Agency (EPA) safe for human hearing."

So, yeah, it's loud. I didn't test the decibel reading with the phone at 100% volume because my cats would probably never forgive me.

Okay, enough with the decibels.

The specs

30W racetrack subwoofer (a type of subwoofer with a rectangular or oval shape, similar to a racetrack), dual-engineered 10 W tweeters, and 2.1 channel audio 50W sound
20 hours of playtime
IPX7 waterproof
Custom EQ via the Tronsmart app
Retractable handle
Built-in power bank to charge other devices
Beat-driven lights
Bass enhancement with SoundPulse
Price - $99

My experience

As I mentioned earlier, the Tronsmart Mirtune S100 speaker is loud. At the same time, it really does need the Tronsmart app to get the best sound. Out of the box, the sound is fairly hollow, with muddy lows and dull highs. Once I had the app connected to the speaker (which was surprisingly easy), I immediately went to the EQ tab and created a custom curve. 

Unfortunately (as I've mentioned with other Tronsmart speakers), the EQ is limited to 5 bands, so you're limited in how much you can adjust. Even so, with my usual curve (increased bass, lower mids, and increased highs), I was able to get some pretty decent sound from the S100.

Also: I changed these 5 soundbar settings for a better TV viewing (and audio) experience

I tend to be fairly forgiving of Bluetooth speakers because, by design, they cannot compete with the sound produced by wired speakers. And when a speaker sells for less than $100, you already know what you're getting into.

That being said, with only a 5-band EQ at the ready and the decibels the S100 can produce, this baby is a steal.

Jack Wallen/ZDNET

Going through my usual test playlist, what jumped out at me (even with my custom EQ curve) is that there's not a lot of definition to the various frequencies. Although that's fairly typical when dealing with such a minimal equalizer, it's slightly more pronounced with the S100. I had to dial down the mids quite a bit to get rid of the tinny nature of small speakers and wasn't ever really able to get much punch on the low end. But, again, this isn't an audiophile-grade speaker.\

Also: One of the loudest Bluetooth speakers I've tested is also one of the most affordable

After listening to a good amount of music through the S100, here are my conclusions:

Alt-rock (such as Mazzy Star) is one of the better-sounding genres with this speaker. Of course, hearing Hope Sandoval through just about anything is a delight. Metal - the low end gets pretty muddy, but it can handle the genre without much distortion, no matter how loud you crank it. Although I will say that Devin Townsend's new tunes really shine.
Classical - with a fairly narrow soundstage, it's hard to hear any separation of voices or instruments but the genre fared fairly well.
Pop - even with the custom EQ, pop music did tend to sound a bit hollow and tinny.
Classic rock - Van Halen sounded a bit crisper than other bands, which is primarily due to the mastering of their albums. AC/DC was respectable, and Kansas was clean, which led me to conclude that classic rock was every bit as good as alt-rock through the S100.
Funk - The S100 really doesn't have the bass to do funk justice, but apart from the low-end, it was certainly serviceable. I don't know if this speaker would be George Clinton-approved, but what he doesn't know won't hurt him.
80s - music from the 80s sounds good through just about any speaker, so it's almost unfair to include the genre. Even so, Saga's "Worlds Apart" album really stood out for me (especially "The Interview" from "Worlds Apart").

ZDNET's buying advice

Anyone who doesn't consider themselves audiophile-adjacent will appreciate the Tronsmart Mirtune S100 Bluetooth speaker, even if only for the amount of sound it can produce.

It's simple: if you don't expect the high-resolution sound produced by far costlier speakers, the Tronsmart Mirtune S100 will serve you well. It's rugged, easy to carry, has a built-in power bank (for when your phone gets low on juice), and is really, really loud.

If that sounds like the makings of a winner to you, then head over to the Tronsmart store (or Amazon), purchase a Mirtune S100 Bluetooth speaker, and crank up the noise and the funk.