The Subwoofer DIY Page
Bluetooth Speakers - the Tribit Stormbox Micro 2

15 August 2022


The Tribit Stormbox Micro 2 is a bluetooth speaker that I purchased from Amazon during July 2022.  This time around, I was looking for a Bluetooth speaker that I could securely fasten to something I was carrying, to allow me to listen to music while I was hashing or hiking. I also wanted a Bluetooth speaker that at least offered an IPX7 rating as I wanted it to be waterproof.  As usual, after viewing many, many Youtube videos of various bluetooth speakers being tested, I decided to go with the Tribit Stormbox Micro 2, as it was a suitable size, it had a built-in strap which could be used to fasten it to various items (in my case the strap for my camera bag), it was quite small and the reviews of the Stormbox Micro 2 generally seemed to be positive.

I took the Stormbox Micro 2 out for a spin yesterday (13th August 2022) on my first hash after three weeks of being confined to home as I didn't have use of my car.  I used the Stormbox Micro 2's rubber strap to fasten it to my camera bag, paired it to my "hash" phone (an old Samsung S7 Edge), set it a reasonable volume (loud enough for me to hear, but not so loud as to disturb other hashers) and set off on the hash, which turned out to be a trail that was about an hour and a half long, mostly through bush and up and down the hillside. At first I was a bit worried about the strap coming loose, which would result in the speaker going off on its own trail, but it remained securely fastened where I placed it, and after a short while I stopped worrying about it.  The music was basically tracks from my Deezer "Driving Time" play list, including songs from Swedish House Mafia, Deadmau5, Gummibear and Fred Again, amongst others.

How was the experience? Well, much better than I expected, with the Stormbox Micro 2 sounding very clear with a tone that appeared to be much warmer than I would have expected from a speaker this size. I suspect that the warm-sounding tone of the speaker might be due to it being mounted decidely off-axis (the speaker facing in the direction I was walking, rather than at my ears), but it sounded great nevertheless. I also tried listening to the Stormbox Micro 2 at different volumes during the hash, turning it up when I was alone, and turning it back down again when I was in the company of other hashers to ensure that I was not making a nuisance of myself. The Stormbox Micro 2 definitely has a volume "sweet spot", above which it starts to noticeably reduce the bass response and distortion becomes very audible.  However it still gets more than loud enough for what I consider to be a "personal" Bluetooth speaker (i.e. one that is attached to you and is primarily for your personal enjoyment, and perhaps those of a few people that are close by). It got loud enough to get a few fellow hashers dancing when Gummibear's "Supernova" came on when I was passing through a group of them, for example. And it definitely sounded a lot better than the larger but tinny-sounding Bluetooth speaker that another hasher was carrying.    

My measurements of the Stormbox Micro 2's performance confirm what I experienced, with a generally downward-sloping response from about 200 Hz onwards when measured off-axis (which I expect to be the usual way that I'll be listening to it). Response drops like a rock below 70 Hz, but this is only to be expected from a speaker that size. The measurements also show the bass being reduced a bit as the volume approached maximum level and I wouldn't suggest turning it up that loud anyway.  If you're looking for a Bluetooth speaker to use for a group of people rather than just yourself, I'd suggest looking for one that's larger and more capable of louder performance without restrictions. Note: I used a Bluetooth connection to the Stormbox Micro 2 to perform the measurements as it doesn't provide an AUX-IN port. The test signal was a simple 20 Hz to 20 kHs sine-sweep generated by Room EQ Wizard's measurement routine. Measurements were performed at 1M using a calibrated UMM6 USB microphone and I used my room transfer function method to estimate bass response at low frequencies. 


Pictured below is the distortion curves for the Stormbox Micro 2 at the -6dB SPL level that I performed the frequency response measurements (the point at which it seemed that the bass was just starting to be lowered in leve). The measurement was taken with the mike at the 1M position.


The distortion graph shows the THD peaking around 100 Hz (mostly 2nd order - a good thing), reducing a bit between 100 Hz and 70 Hz (probably due to the passive radiators located on either side of the Stormbox Micro 2) and then increasing below that (where the passive radiators and the main driver are now out of phase, and there is no useful bass response). IMO this is very decent performance for a speaker this size.   

Overall I like the Tribit Stormbox Micro 2.  It has an unexpected warm tone for a speaker of its size and actually gets down to 70 Hz, so most music played back on it should sound pretty good. My only concerns about it are the uncovered charge port (a curious decision for an IP67-rated speaker) and the longetivity of the rubberized finish at the bottom of the speaker (a lot of those rubberized finishes don't seem to last long in the Tropics...).



Brian Steele
15 August 2022