Our testing took place at our offices in the audio studio (indoor) at a wedding reception (hall) and finally outdoors at a school sports event, and there is a definite difference even though the powered amp and speakers are the same specifications.
From Audxtreme™’s point of view, both speakers do the job with good sound quality, however, if we had to choose what we would prefer then our answer would be the MKI.
Why? The MKI is better looking and has 2 handles for carrying and lifting (in particular). The MKII sports only 1 handle and it’s rather difficult to lift the powered speaker onto a tripod stand. Secondly, the MKI seems to push out more power at the same set level as the MKII, and this power can be heard with the ear and without any measuring devices.
In conclusion, and in our opinion, we believe that the power or sound difference is the design of the actual composite speaker cabinet, the MKI seems to have better dispersion and that could be the additional power it provides. Overall both Hybrid PB15AUB the MKI and MKII powered speakers are good speakers and offer serious sound comparability to speakers in the same class.