Ohh, I love my Minirig Mini 
I’m constantly (pleasantly) surprised at the sheer volume it produces. I don’t know about frequency response (I’m not that technical) but I think there’s a goodly bump in the midrange - but then, they aren’t sold as studio standard, flat response and all that. (range is 70Hz to 16KHz according to https://minirigs.co.uk/speakers/bluetooth-minirig-mini ) - They’re more of a “throw it in your bag and go” kinda thing, I think.
But for a good, solid, all-rounder, it suits my needs perfectly - Lately I’ve had it plugged into my mixer but I also use it on my laptop, and mobile phone.
For the price (£100 which I think is a shade under $130), I don’t think you can go wrong, tbh!
Edit: Battery life is impressive, too 